/* roulang page: index */
/* ===== Design Variables ===== */
:root {
  --primary: #00d4ff;
  --primary-dark: #0099cc;
  --primary-glow: rgba(0, 212, 255, 0.25);
  --secondary: #7c3aed;
  --secondary-glow: rgba(124, 58, 237, 0.25);
  --accent: #00ff88;
  --accent-glow: rgba(0, 255, 136, 0.2);
  --bg-body: #080c18;
  --bg-card: #10182e;
  --bg-card-hover: #1a2542;
  --bg-sidebar: #0b1120;
  --bg-surface: #141e36;
  --bg-elevated: #1c2848;
  --text-primary: #e8edf5;
  --text-secondary: #8a94b0;
  --text-muted: #4e5880;
  --border-color: #1e2d4a;
  --border-glow: rgba(0, 212, 255, 0.12);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --shadow-sm: 0 2px 12px rgba(0,0,0,0.25);
  --shadow-md: 0 8px 32px rgba(0,0,0,0.35);
  --shadow-lg: 0 20px 60px rgba(0,0,0,0.5);
  --shadow-glow: 0 0 30px rgba(0, 212, 255, 0.08);
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
  --sidebar-width: 240px;
  --header-height: 0px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }
body {
  font-family: var(--font-family);
  background: var(--bg-body);
  color: var(--text-primary);
  line-height: 1.65;
  overflow-x: hidden;
  min-height: 100vh;
}
a { color: var(--primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: #66e5ff; }
a:focus-visible { outline: 2px solid var(--primary); outline-offset: 3px; border-radius: 4px; }
img { max-width: 100%; height: auto; display: block; border-radius: var(--radius-sm); }
button, input, textarea, select { font-family: inherit; font-size: inherit; }
button { cursor: pointer; border: none; background: none; color: inherit; }
ul, ol { list-style: none; }
h1, h2, h3, h4, h5, h6 { line-height: 1.25; font-weight: 700; color: var(--text-primary); }
h1 { font-size: clamp(2.2rem, 5vw, 3.8rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.6rem, 3vw, 2.6rem); letter-spacing: -0.01em; }
h3 { font-size: clamp(1.2rem, 1.8vw, 1.6rem); }
h4 { font-size: 1.15rem; }
p { margin-bottom: 1rem; color: var(--text-secondary); }
::selection { background: var(--primary); color: #000; }

/* ===== Container ===== */
.container {
  width: 100%;
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 28px;
}

/* ===== App Shell Layout ===== */
.app-shell {
  display: flex;
  min-height: 100vh;
}

/* ===== Sidebar ===== */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  z-index: 1000;
  transition: transform var(--transition), box-shadow var(--transition);
  overflow-y: auto;
  backdrop-filter: blur(8px);
}
.sidebar-logo {
  padding: 28px 22px 20px;
  border-bottom: 1px solid var(--border-color);
}
.sidebar-logo a {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.03em;
  display: flex;
  align-items: center;
  gap: 10px;
}
.sidebar-logo a i {
  color: var(--primary);
  font-size: 1.6rem;
  text-shadow: 0 0 20px var(--primary-glow);
}
.sidebar-logo a:hover { color: var(--primary); }
.sidebar-nav {
  padding: 18px 14px;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.sidebar-nav .nav-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  transition: all var(--transition);
  position: relative;
}
.sidebar-nav .nav-item i {
  width: 20px;
  text-align: center;
  font-size: 1.05rem;
  color: var(--text-muted);
  transition: color var(--transition);
}
.sidebar-nav .nav-item:hover {
  background: rgba(0, 212, 255, 0.06);
  color: var(--text-primary);
}
.sidebar-nav .nav-item:hover i { color: var(--primary); }
.sidebar-nav .nav-item.active {
  background: rgba(0, 212, 255, 0.10);
  color: var(--primary);
  font-weight: 600;
  box-shadow: inset 3px 0 0 var(--primary);
}
.sidebar-nav .nav-item.active i { color: var(--primary); }
.sidebar-footer {
  padding: 18px 22px;
  border-top: 1px solid var(--border-color);
  font-size: 0.75rem;
  color: var(--text-muted);
  text-align: center;
}

/* ===== Main Content ===== */
.main-content {
  flex: 1;
  margin-left: var(--sidebar-width);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ===== Mobile Header (hidden on desktop) ===== */
.mobile-header {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 60px;
  background: rgba(8, 12, 24, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  z-index: 999;
  padding: 0 18px;
  align-items: center;
  justify-content: space-between;
}
.mobile-header .logo-text {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
}
.mobile-header .logo-text i { color: var(--primary); }
.mobile-hamburger {
  width: 42px;
  height: 42px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 1.4rem;
  transition: background var(--transition);
}
.mobile-hamburger:hover { background: rgba(255,255,255,0.06); }
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  z-index: 998;
  opacity: 0;
  transition: opacity var(--transition);
  pointer-events: none;
}
.sidebar-overlay.open { opacity: 1; pointer-events: auto; }

/* ===== Hero Section ===== */
.hero {
  position: relative;
  padding: 80px 0 90px;
  background: linear-gradient(135deg, #0a0e1e 0%, #0f1a30 40%, #0d1a2a 100%);
  overflow: hidden;
  min-height: 520px;
  display: flex;
  align-items: center;
}
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url('/assets/images/backpic/back-1.png') center center / cover no-repeat;
  opacity: 0.20;
  mix-blend-mode: screen;
  animation: heroParallax 30s ease-in-out infinite alternate;
}
@keyframes heroParallax {
  0% { transform: scale(1) translate(0, 0); }
  100% { transform: scale(1.05) translate(-8px, -8px); }
}
.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 30% 50%, rgba(0, 212, 255, 0.06) 0%, transparent 70%),
              radial-gradient(ellipse at 70% 20%, rgba(124, 58, 237, 0.04) 0%, transparent 60%);
  pointer-events: none;
}
.hero .container { position: relative; z-index: 2; }
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(0, 212, 255, 0.10);
  border: 1px solid rgba(0, 212, 255, 0.18);
  border-radius: 100px;
  padding: 6px 18px 6px 12px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--primary);
  letter-spacing: 0.04em;
  margin-bottom: 28px;
  backdrop-filter: blur(4px);
}
.hero-badge i { font-size: 0.7rem; }
.hero h1 {
  max-width: 800px;
  margin-bottom: 22px;
  background: linear-gradient(135deg, #f0f5ff 0%, #80d4ff 40%, #a78bfa 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero p {
  font-size: 1.2rem;
  max-width: 580px;
  margin-bottom: 36px;
  color: var(--text-secondary);
  line-height: 1.7;
}
.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: center;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 32px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  transition: all var(--transition);
  border: 1px solid transparent;
  position: relative;
  overflow: hidden;
}
.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #000;
  border-color: var(--primary);
  box-shadow: 0 0 24px rgba(0, 212, 255, 0.20);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 40px rgba(0, 212, 255, 0.35);
  color: #000;
}
.btn-outline {
  background: transparent;
  color: var(--text-primary);
  border-color: var(--border-color);
}
.btn-outline:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: rgba(0, 212, 255, 0.04);
  transform: translateY(-2px);
}
.btn-glow {
  background: rgba(0, 212, 255, 0.04);
  color: var(--primary);
  border-color: rgba(0, 212, 255, 0.25);
  backdrop-filter: blur(4px);
}
.btn-glow:hover {
  background: rgba(0, 212, 255, 0.12);
  box-shadow: 0 0 32px rgba(0, 212, 255, 0.15);
  transform: translateY(-2px);
  color: var(--primary);
}
.hero-stats {
  display: flex;
  gap: 40px;
  margin-top: 50px;
  padding-top: 40px;
  border-top: 1px solid rgba(255,255,255,0.05);
}
.hero-stat h3 {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}
.hero-stat h3 span { color: var(--primary); }
.hero-stat p {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 0;
}

/* ===== Section Common ===== */
.section {
  padding: 70px 0;
}
.section-header {
  text-align: center;
  margin-bottom: 52px;
}
.section-header h2 {
  margin-bottom: 14px;
}
.section-header p {
  max-width: 540px;
  margin: 0 auto;
  font-size: 1.05rem;
}
.section-divider {
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  border-radius: 4px;
  margin: 16px auto 0;
}

/* ===== Intro / About ===== */
.intro-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 50px;
  align-items: center;
}
.intro-image {
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  position: relative;
}
.intro-image::after {
  content: '';
  position: absolute;
  inset: 0;
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-md);
  pointer-events: none;
}
.intro-image img {
  width: 100%;
  min-height: 300px;
  object-fit: cover;
  background: var(--bg-card);
}
.intro-text h3 {
  font-size: 1.5rem;
  margin-bottom: 16px;
}
.intro-text p {
  margin-bottom: 18px;
  font-size: 1rem;
}
.tag {
  display: inline-block;
  padding: 4px 14px;
  border-radius: 100px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  background: rgba(0, 212, 255, 0.08);
  color: var(--primary);
  border: 1px solid rgba(0, 212, 255, 0.12);
  margin-right: 6px;
  margin-bottom: 6px;
}
.tag-purple {
  background: rgba(124, 58, 237, 0.08);
  color: var(--secondary);
  border-color: rgba(124, 58, 237, 0.15);
}
.tag-green {
  background: rgba(0, 255, 136, 0.08);
  color: var(--accent);
  border-color: rgba(0, 255, 136, 0.12);
}

/* ===== Category Cards ===== */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 30px;
}
.cat-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: all var(--transition);
  position: relative;
}
.cat-card:hover {
  transform: translateY(-6px);
  border-color: rgba(0, 212, 255, 0.20);
  box-shadow: var(--shadow-glow), var(--shadow-md);
}
.cat-card-image {
  height: 200px;
  overflow: hidden;
  position: relative;
  background: var(--bg-surface);
}
.cat-card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.6s ease;
}
.cat-card:hover .cat-card-image img { transform: scale(1.05); }
.cat-card-image::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 60%;
  background: linear-gradient(transparent, var(--bg-card));
  pointer-events: none;
}
.cat-card-body {
  padding: 22px 26px 28px;
}
.cat-card-body h3 {
  font-size: 1.3rem;
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.cat-card-body h3 i { color: var(--primary); font-size: 1.1rem; }
.cat-card-body p {
  font-size: 0.92rem;
  color: var(--text-secondary);
  margin-bottom: 18px;
}
.cat-card-meta {
  display: flex;
  gap: 18px;
  font-size: 0.8rem;
  color: var(--text-muted);
}
.cat-card-meta i { margin-right: 4px; }

/* ===== Latest Posts ===== */
.posts-list {
  display: flex;
  flex-direction: column;
  gap: 18px;
}
.post-item {
  display: flex;
  align-items: flex-start;
  gap: 20px;
  padding: 20px 24px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}
.post-item:hover {
  border-color: rgba(0, 212, 255, 0.15);
  background: var(--bg-card-hover);
  transform: translateX(4px);
}
.post-item-icon {
  width: 44px;
  height: 44px;
  flex-shrink: 0;
  border-radius: var(--radius-sm);
  background: rgba(0, 212, 255, 0.06);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  color: var(--primary);
}
.post-item-content {
  flex: 1;
  min-width: 0;
}
.post-item-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 4px;
  display: block;
  transition: color var(--transition);
}
.post-item-title:hover { color: var(--primary); }
.post-item-excerpt {
  font-size: 0.88rem;
  color: var(--text-secondary);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-bottom: 0;
}
.post-item-meta {
  display: flex;
  gap: 16px;
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-top: 8px;
}
.post-item-meta span { display: flex; align-items: center; gap: 4px; }
.post-item-meta .cat-tag {
  background: rgba(0, 212, 255, 0.06);
  color: var(--primary);
  padding: 1px 10px;
  border-radius: 100px;
  font-size: 0.72rem;
  font-weight: 500;
}
.empty-posts {
  text-align: center;
  padding: 50px 20px;
  color: var(--text-muted);
  font-size: 1rem;
  background: var(--bg-card);
  border-radius: var(--radius-sm);
  border: 1px dashed var(--border-color);
}
.empty-posts i { font-size: 2rem; margin-bottom: 12px; display: block; color: var(--text-muted); }

/* ===== Features / Data ===== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}
.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 32px 28px;
  text-align: center;
  transition: all var(--transition);
}
.feature-card:hover {
  border-color: rgba(0, 212, 255, 0.12);
  transform: translateY(-4px);
  box-shadow: var(--shadow-glow);
}
.feature-icon {
  width: 60px;
  height: 60px;
  margin: 0 auto 18px;
  border-radius: var(--radius-sm);
  background: rgba(0, 212, 255, 0.06);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  color: var(--primary);
  transition: all var(--transition);
}
.feature-card:hover .feature-icon {
  background: rgba(0, 212, 255, 0.12);
  box-shadow: 0 0 30px rgba(0, 212, 255, 0.08);
}
.feature-card h4 { margin-bottom: 10px; font-size: 1.1rem; }
.feature-card p { font-size: 0.9rem; margin-bottom: 0; }

/* ===== Stats Row ===== */
.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 40px 30px;
}
.stat-item {
  text-align: center;
}
.stat-item .stat-number {
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  line-height: 1.2;
}
.stat-item .stat-number i { color: var(--primary); font-style: normal; }
.stat-item .stat-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 6px;
}

/* ===== FAQ ===== */
.faq-list {
  max-width: 760px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  overflow: hidden;
  transition: all var(--transition);
}
.faq-item:hover { border-color: rgba(0, 212, 255, 0.10); }
.faq-question {
  padding: 18px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
  font-size: 1rem;
  color: var(--text-primary);
  cursor: pointer;
  transition: color var(--transition);
  width: 100%;
  text-align: left;
  background: none;
  border: none;
}
.faq-question:hover { color: var(--primary); }
.faq-question i { color: var(--text-muted); transition: transform var(--transition); font-size: 0.9rem; }
.faq-item.open .faq-question i { transform: rotate(180deg); color: var(--primary); }
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.3s ease;
  padding: 0 24px;
}
.faq-item.open .faq-answer {
  max-height: 300px;
  padding: 0 24px 20px;
}
.faq-answer p {
  font-size: 0.92rem;
  color: var(--text-secondary);
  margin-bottom: 0;
}

/* ===== CTA ===== */
.cta-section {
  background: linear-gradient(135deg, #0d1a2a 0%, #10182e 50%, #0f1a30 100%);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  position: relative;
  overflow: hidden;
}
.cta-section::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url('/assets/images/backpic/back-2.png') center center / cover no-repeat;
  opacity: 0.06;
  mix-blend-mode: screen;
}
.cta-box {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 60px 20px;
}
.cta-box h2 { margin-bottom: 14px; }
.cta-box p { max-width: 500px; margin: 0 auto 32px; font-size: 1.05rem; }
.cta-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* ===== Footer ===== */
.site-footer {
  background: var(--bg-sidebar);
  border-top: 1px solid var(--border-color);
  padding: 48px 0 28px;
  margin-top: auto;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 36px;
}
.footer-brand .logo-text {
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 12px;
}
.footer-brand .logo-text i { color: var(--primary); }
.footer-brand p {
  font-size: 0.88rem;
  color: var(--text-muted);
  max-width: 260px;
}
.footer-col h5 {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 16px;
  letter-spacing: 0.02em;
}
.footer-col a {
  display: block;
  font-size: 0.88rem;
  color: var(--text-muted);
  padding: 5px 0;
  transition: color var(--transition);
}
.footer-col a:hover { color: var(--primary); }
.footer-col a i { width: 18px; margin-right: 6px; color: var(--text-muted); }
.footer-bottom {
  border-top: 1px solid var(--border-color);
  padding-top: 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 0.8rem;
  color: var(--text-muted);
}
.footer-bottom a { color: var(--text-muted); }
.footer-bottom a:hover { color: var(--primary); }

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .stats-row { grid-template-columns: repeat(2, 1fr); gap: 20px; }
  .footer-grid { grid-template-columns: repeat(2, 1fr); gap: 30px; }
}

@media (max-width: 768px) {
  .sidebar { transform: translateX(-100%); }
  .sidebar.open { transform: translateX(0); box-shadow: 0 0 60px rgba(0,0,0,0.6); }
  .mobile-header { display: flex; }
  .main-content { margin-left: 0; padding-top: 60px; }
  .hero { padding: 50px 0 60px; min-height: auto; }
  .hero-stats { gap: 24px; flex-wrap: wrap; }
  .hero-stat h3 { font-size: 1.4rem; }
  .intro-grid { grid-template-columns: 1fr; gap: 30px; }
  .cat-grid { grid-template-columns: 1fr; }
  .features-grid { grid-template-columns: 1fr; }
  .stats-row { grid-template-columns: repeat(2, 1fr); padding: 28px 18px; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 24px; }
  .footer-bottom { flex-direction: column; text-align: center; }
  .section { padding: 50px 0; }
  .container { padding: 0 18px; }
  .post-item { flex-direction: column; gap: 12px; padding: 16px 18px; }
  .post-item-icon { width: 36px; height: 36px; font-size: 1rem; }
  .sidebar-overlay.open { display: block; }
}

@media (max-width: 520px) {
  .hero h1 { font-size: 1.8rem; }
  .hero p { font-size: 1rem; }
  .hero-actions { flex-direction: column; width: 100%; }
  .hero-actions .btn { width: 100%; justify-content: center; }
  .hero-stats { flex-direction: column; gap: 16px; }
  .stats-row { grid-template-columns: 1fr 1fr; gap: 14px; padding: 20px 12px; }
  .stat-item .stat-number { font-size: 1.6rem; }
  .footer-grid { grid-template-columns: 1fr; text-align: center; }
  .footer-brand p { max-width: 100%; }
  .cat-card-body { padding: 16px 18px 22px; }
  .cta-box { padding: 40px 14px; }
  .cta-actions { flex-direction: column; }
  .cta-actions .btn { width: 100%; justify-content: center; }
  .faq-question { padding: 14px 16px; font-size: 0.92rem; }
  .faq-item.open .faq-answer { padding: 0 16px 16px; }
}

/* ===== Utility ===== */
.text-gradient { background: linear-gradient(135deg, var(--primary), var(--secondary)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.glow { text-shadow: 0 0 40px rgba(0, 212, 255, 0.15); }
.mt-1 { margin-top: 8px; }
.mt-2 { margin-top: 16px; }
.mt-3 { margin-top: 24px; }
.mb-1 { margin-bottom: 8px; }
.mb-2 { margin-bottom: 16px; }
.mb-3 { margin-bottom: 24px; }
.text-center { text-align: center; }

/* roulang page: article */
/* ===== Design Variables ===== */
        :root {
            --primary: #6c5ce7;
            --primary-light: #a29bfe;
            --primary-dark: #4834d4;
            --secondary: #fd79a8;
            --accent: #00cec9;
            --bg-dark: #0a0a1a;
            --bg-card: #12122a;
            --bg-surface: #1a1a3e;
            --bg-input: #16163a;
            --text-primary: #f0f0ff;
            --text-secondary: #b0b0d0;
            --text-muted: #7070a0;
            --border-color: #2a2a5a;
            --border-light: #3a3a6a;
            --radius-sm: 6px;
            --radius-md: 12px;
            --radius-lg: 20px;
            --shadow-sm: 0 2px 8px rgba(108, 92, 231, 0.08);
            --shadow-md: 0 8px 32px rgba(108, 92, 231, 0.12);
            --shadow-lg: 0 16px 48px rgba(108, 92, 231, 0.18);
            --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            --sidebar-width: 220px;
            --header-height: 0px;
        }

        /* ===== Reset & Base ===== */
        *,
        *::before,
        *::after {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }
        html {
            scroll-behavior: smooth;
            font-size: 16px;
        }
        body {
            font-family: var(--font-sans);
            background: var(--bg-dark);
            color: var(--text-primary);
            line-height: 1.7;
            min-height: 100vh;
            display: flex;
        }
        a {
            color: var(--primary-light);
            text-decoration: none;
            transition: color var(--transition);
        }
        a:hover {
            color: #fff;
        }
        a:focus-visible {
            outline: 2px solid var(--accent);
            outline-offset: 2px;
            border-radius: 4px;
        }
        img {
            max-width: 100%;
            height: auto;
            display: block;
            border-radius: var(--radius-md);
        }
        button,
        input,
        textarea {
            font-family: inherit;
            font-size: 1rem;
            border: none;
            outline: none;
            background: none;
            color: inherit;
        }
        button {
            cursor: pointer;
        }
        ul,
        ol {
            list-style: none;
        }
        h1,
        h2,
        h3,
        h4,
        h5,
        h6 {
            font-weight: 700;
            line-height: 1.3;
            color: #fff;
        }
        h1 {
            font-size: 2.4rem;
        }
        h2 {
            font-size: 1.8rem;
        }
        h3 {
            font-size: 1.4rem;
        }
        h4 {
            font-size: 1.2rem;
        }
        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 24px;
            width: 100%;
        }

        /* ===== Sidebar Navigation ===== */
        .sidebar {
            position: fixed;
            top: 0;
            left: 0;
            width: var(--sidebar-width);
            height: 100vh;
            background: var(--bg-card);
            border-right: 1px solid var(--border-color);
            display: flex;
            flex-direction: column;
            z-index: 1000;
            padding: 28px 16px;
            backdrop-filter: blur(12px);
            transition: transform var(--transition);
        }
        .sidebar-logo {
            display: flex;
            align-items: center;
            gap: 10px;
            font-size: 1.3rem;
            font-weight: 800;
            color: #fff;
            padding: 0 12px 24px;
            border-bottom: 1px solid var(--border-color);
            margin-bottom: 24px;
        }
        .sidebar-logo i {
            color: var(--primary-light);
            font-size: 1.5rem;
        }
        .sidebar-logo span {
            background: linear-gradient(135deg, var(--primary-light), var(--secondary));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }
        .sidebar-nav {
            display: flex;
            flex-direction: column;
            gap: 6px;
            flex: 1;
        }
        .sidebar-nav .nav-item {
            display: flex;
            align-items: center;
            gap: 12px;
            padding: 12px 16px;
            border-radius: var(--radius-md);
            color: var(--text-secondary);
            font-weight: 500;
            font-size: 0.95rem;
            transition: all var(--transition);
            position: relative;
        }
        .sidebar-nav .nav-item i {
            width: 20px;
            text-align: center;
            font-size: 1.1rem;
            color: var(--text-muted);
            transition: color var(--transition);
        }
        .sidebar-nav .nav-item:hover {
            background: rgba(108, 92, 231, 0.1);
            color: #fff;
        }
        .sidebar-nav .nav-item:hover i {
            color: var(--primary-light);
        }
        .sidebar-nav .nav-item.active {
            background: rgba(108, 92, 231, 0.18);
            color: #fff;
            box-shadow: inset 0 0 0 1px rgba(108, 92, 231, 0.3);
        }
        .sidebar-nav .nav-item.active i {
            color: var(--primary-light);
        }
        .sidebar-nav .nav-item.active::before {
            content: '';
            position: absolute;
            left: -16px;
            top: 50%;
            transform: translateY(-50%);
            width: 4px;
            height: 24px;
            background: var(--primary-light);
            border-radius: 0 4px 4px 0;
        }
        .sidebar-footer {
            padding-top: 16px;
            border-top: 1px solid var(--border-color);
            font-size: 0.8rem;
            color: var(--text-muted);
            text-align: center;
        }

        /* ===== Main Content Area ===== */
        .main-wrapper {
            margin-left: var(--sidebar-width);
            flex: 1;
            min-height: 100vh;
            display: flex;
            flex-direction: column;
        }

        /* ===== Mobile Header ===== */
        .mobile-header {
            display: none;
            position: sticky;
            top: 0;
            z-index: 999;
            background: var(--bg-card);
            border-bottom: 1px solid var(--border-color);
            padding: 12px 20px;
            align-items: center;
            justify-content: space-between;
            backdrop-filter: blur(12px);
        }
        .mobile-header .logo-text {
            display: flex;
            align-items: center;
            gap: 8px;
            font-size: 1.15rem;
            font-weight: 700;
            color: #fff;
        }
        .mobile-header .logo-text i {
            color: var(--primary-light);
        }
        .mobile-menu-btn {
            background: none;
            border: none;
            color: var(--text-primary);
            font-size: 1.5rem;
            padding: 4px 8px;
            border-radius: var(--radius-sm);
            transition: background var(--transition);
        }
        .mobile-menu-btn:hover {
            background: rgba(108, 92, 231, 0.15);
        }
        .mobile-overlay {
            display: none;
            position: fixed;
            inset: 0;
            background: rgba(0, 0, 0, 0.6);
            z-index: 998;
            backdrop-filter: blur(4px);
        }
        .mobile-overlay.open {
            display: block;
        }
        .sidebar.open {
            transform: translateX(0);
        }

        /* ===== Article Hero Banner ===== */
        .article-hero {
            position: relative;
            padding: 60px 0 48px;
            background: linear-gradient(135deg, var(--bg-dark) 0%, var(--bg-card) 50%, rgba(108, 92, 231, 0.08) 100%);
            border-bottom: 1px solid var(--border-color);
        }
        .article-hero::before {
            content: '';
            position: absolute;
            inset: 0;
            background: url('/assets/images/backpic/back-1.png') center/cover no-repeat;
            opacity: 0.06;
            pointer-events: none;
        }
        .article-hero .container {
            position: relative;
            z-index: 1;
        }
        .article-breadcrumb {
            display: flex;
            align-items: center;
            gap: 8px;
            font-size: 0.85rem;
            color: var(--text-muted);
            margin-bottom: 20px;
            flex-wrap: wrap;
        }
        .article-breadcrumb a {
            color: var(--text-muted);
        }
        .article-breadcrumb a:hover {
            color: var(--primary-light);
        }
        .article-breadcrumb .separator {
            color: var(--border-light);
        }
        .article-breadcrumb .current {
            color: var(--text-secondary);
        }
        .article-category-badge {
            display: inline-block;
            padding: 4px 14px;
            border-radius: 20px;
            font-size: 0.8rem;
            font-weight: 600;
            background: rgba(108, 92, 231, 0.2);
            color: var(--primary-light);
            border: 1px solid rgba(108, 92, 231, 0.3);
            margin-bottom: 16px;
        }
        .article-hero h1 {
            font-size: 2.6rem;
            max-width: 900px;
            line-height: 1.25;
            margin-bottom: 16px;
            background: linear-gradient(135deg, #fff 60%, var(--primary-light));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }
        .article-meta {
            display: flex;
            align-items: center;
            gap: 20px;
            flex-wrap: wrap;
            color: var(--text-muted);
            font-size: 0.9rem;
        }
        .article-meta i {
            margin-right: 4px;
            color: var(--primary-light);
        }
        .article-meta span {
            display: flex;
            align-items: center;
            gap: 4px;
        }

        /* ===== Article Content ===== */
        .article-section {
            padding: 48px 0 60px;
        }
        .article-layout {
            display: grid;
            grid-template-columns: 1fr 300px;
            gap: 48px;
        }
        .article-body {
            min-width: 0;
        }
        .article-body .content {
            font-size: 1.05rem;
            line-height: 1.9;
            color: var(--text-secondary);
        }
        .article-body .content p {
            margin-bottom: 1.2em;
        }
        .article-body .content h2,
        .article-body .content h3 {
            margin-top: 1.6em;
            margin-bottom: 0.6em;
            color: #fff;
        }
        .article-body .content h2 {
            font-size: 1.6rem;
        }
        .article-body .content h3 {
            font-size: 1.3rem;
        }
        .article-body .content ul,
        .article-body .content ol {
            margin-bottom: 1.2em;
            padding-left: 1.5em;
        }
        .article-body .content li {
            margin-bottom: 0.4em;
            list-style: disc;
        }
        .article-body .content a {
            color: var(--accent);
            text-decoration: underline;
        }
        .article-body .content a:hover {
            color: #fff;
        }
        .article-body .content blockquote {
            border-left: 4px solid var(--primary-light);
            background: rgba(108, 92, 231, 0.06);
            padding: 16px 24px;
            margin: 1.5em 0;
            border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
            color: var(--text-secondary);
            font-style: italic;
        }
        .article-body .content img {
            margin: 1.5em auto;
            border-radius: var(--radius-md);
            box-shadow: var(--shadow-md);
            max-width: 100%;
        }
        .article-body .content code {
            background: var(--bg-surface);
            padding: 2px 8px;
            border-radius: 4px;
            font-size: 0.9em;
            color: var(--secondary);
        }
        .article-body .content pre {
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-md);
            padding: 20px 24px;
            overflow-x: auto;
            margin: 1.5em 0;
        }
        .article-body .content pre code {
            background: none;
            padding: 0;
            color: var(--text-secondary);
        }
        .article-tags {
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
            margin-top: 32px;
            padding-top: 24px;
            border-top: 1px solid var(--border-color);
        }
        .article-tags .tag {
            padding: 6px 16px;
            border-radius: 20px;
            font-size: 0.8rem;
            background: var(--bg-surface);
            color: var(--text-secondary);
            border: 1px solid var(--border-color);
            transition: all var(--transition);
        }
        .article-tags .tag:hover {
            background: rgba(108, 92, 231, 0.15);
            border-color: rgba(108, 92, 231, 0.3);
            color: #fff;
        }
        .article-share {
            display: flex;
            align-items: center;
            gap: 12px;
            margin-top: 24px;
            padding-top: 20px;
            border-top: 1px solid var(--border-color);
        }
        .article-share span {
            color: var(--text-muted);
            font-size: 0.9rem;
        }
        .article-share .share-btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            width: 40px;
            height: 40px;
            border-radius: 50%;
            background: var(--bg-surface);
            color: var(--text-secondary);
            border: 1px solid var(--border-color);
            transition: all var(--transition);
            font-size: 1rem;
        }
        .article-share .share-btn:hover {
            background: var(--primary);
            color: #fff;
            border-color: var(--primary);
            transform: translateY(-2px);
        }

        /* ===== Article Sidebar ===== */
        .article-sidebar {
            display: flex;
            flex-direction: column;
            gap: 32px;
        }
        .sidebar-widget {
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-lg);
            padding: 24px;
        }
        .sidebar-widget h4 {
            font-size: 1.05rem;
            margin-bottom: 16px;
            display: flex;
            align-items: center;
            gap: 8px;
        }
        .sidebar-widget h4 i {
            color: var(--primary-light);
        }
        .sidebar-related-list {
            display: flex;
            flex-direction: column;
            gap: 14px;
        }
        .sidebar-related-item {
            display: flex;
            gap: 12px;
            align-items: flex-start;
            padding: 10px 12px;
            border-radius: var(--radius-md);
            transition: background var(--transition);
        }
        .sidebar-related-item:hover {
            background: rgba(108, 92, 231, 0.06);
        }
        .sidebar-related-item .thumb {
            width: 64px;
            height: 48px;
            border-radius: var(--radius-sm);
            object-fit: cover;
            flex-shrink: 0;
            background: var(--bg-surface);
        }
        .sidebar-related-item .info {
            flex: 1;
            min-width: 0;
        }
        .sidebar-related-item .info .title {
            font-size: 0.9rem;
            font-weight: 600;
            color: var(--text-primary);
            line-height: 1.4;
            display: -webkit-box;
            -webkit-line-clamp: 2;
            -webkit-box-orient: vertical;
            overflow: hidden;
        }
        .sidebar-related-item .info .date {
            font-size: 0.78rem;
            color: var(--text-muted);
            margin-top: 4px;
        }
        .sidebar-widget .cat-list {
            display: flex;
            flex-direction: column;
            gap: 8px;
        }
        .sidebar-widget .cat-list a {
            display: flex;
            align-items: center;
            gap: 10px;
            padding: 8px 12px;
            border-radius: var(--radius-sm);
            color: var(--text-secondary);
            font-size: 0.9rem;
            transition: all var(--transition);
        }
        .sidebar-widget .cat-list a:hover {
            background: rgba(108, 92, 231, 0.08);
            color: #fff;
        }
        .sidebar-widget .cat-list a i {
            color: var(--primary-light);
            font-size: 0.8rem;
        }
        .sidebar-cta-box {
            background: linear-gradient(135deg, rgba(108, 92, 231, 0.15), rgba(253, 121, 168, 0.08));
            border: 1px solid rgba(108, 92, 231, 0.2);
            border-radius: var(--radius-lg);
            padding: 24px;
            text-align: center;
        }
        .sidebar-cta-box h5 {
            font-size: 1.1rem;
            margin-bottom: 8px;
        }
        .sidebar-cta-box p {
            font-size: 0.85rem;
            color: var(--text-muted);
            margin-bottom: 16px;
        }
        .sidebar-cta-box .btn {
            display: inline-block;
            padding: 10px 28px;
            border-radius: 50px;
            background: linear-gradient(135deg, var(--primary), var(--secondary));
            color: #fff;
            font-weight: 600;
            font-size: 0.9rem;
            transition: all var(--transition);
        }
        .sidebar-cta-box .btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 24px rgba(108, 92, 231, 0.3);
        }

        /* ===== Related Articles ===== */
        .related-section {
            padding: 48px 0 60px;
            background: var(--bg-card);
            border-top: 1px solid var(--border-color);
            border-bottom: 1px solid var(--border-color);
        }
        .related-section h2 {
            margin-bottom: 32px;
            font-size: 1.6rem;
        }
        .related-section h2 i {
            color: var(--primary-light);
            margin-right: 8px;
        }
        .related-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 24px;
        }
        .related-card {
            background: var(--bg-surface);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-lg);
            overflow: hidden;
            transition: all var(--transition);
        }
        .related-card:hover {
            transform: translateY(-4px);
            border-color: rgba(108, 92, 231, 0.3);
            box-shadow: var(--shadow-md);
        }
        .related-card .card-img {
            width: 100%;
            height: 180px;
            object-fit: cover;
            border-radius: 0;
        }
        .related-card .card-body {
            padding: 18px 20px 20px;
        }
        .related-card .card-body .cat-tag {
            display: inline-block;
            padding: 2px 12px;
            border-radius: 12px;
            font-size: 0.72rem;
            font-weight: 600;
            background: rgba(108, 92, 231, 0.15);
            color: var(--primary-light);
            margin-bottom: 8px;
        }
        .related-card .card-body h3 {
            font-size: 1.05rem;
            margin-bottom: 6px;
            color: #fff;
        }
        .related-card .card-body p {
            font-size: 0.85rem;
            color: var(--text-muted);
            display: -webkit-box;
            -webkit-line-clamp: 2;
            -webkit-box-orient: vertical;
            overflow: hidden;
        }
        .related-card .card-body .date {
            font-size: 0.78rem;
            color: var(--text-muted);
            margin-top: 10px;
        }

        /* ===== CTA Section ===== */
        .article-cta {
            padding: 60px 0;
            background: linear-gradient(135deg, var(--bg-dark) 0%, rgba(108, 92, 231, 0.06) 100%);
            text-align: center;
        }
        .article-cta h2 {
            font-size: 1.8rem;
            margin-bottom: 12px;
        }
        .article-cta p {
            color: var(--text-secondary);
            max-width: 560px;
            margin: 0 auto 28px;
            font-size: 1rem;
        }
        .article-cta .btn-group {
            display: flex;
            gap: 16px;
            justify-content: center;
            flex-wrap: wrap;
        }
        .article-cta .btn-primary {
            padding: 14px 36px;
            border-radius: 50px;
            background: linear-gradient(135deg, var(--primary), var(--secondary));
            color: #fff;
            font-weight: 600;
            font-size: 1rem;
            transition: all var(--transition);
            display: inline-flex;
            align-items: center;
            gap: 8px;
        }
        .article-cta .btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: 0 12px 32px rgba(108, 92, 231, 0.35);
        }
        .article-cta .btn-secondary {
            padding: 14px 36px;
            border-radius: 50px;
            background: transparent;
            color: var(--text-primary);
            font-weight: 600;
            font-size: 1rem;
            border: 1px solid var(--border-light);
            transition: all var(--transition);
            display: inline-flex;
            align-items: center;
            gap: 8px;
        }
        .article-cta .btn-secondary:hover {
            background: rgba(108, 92, 231, 0.1);
            border-color: var(--primary-light);
        }

        /* ===== Footer ===== */
        .site-footer {
            background: var(--bg-card);
            border-top: 1px solid var(--border-color);
            padding: 48px 0 32px;
            margin-top: auto;
        }
        .site-footer .footer-grid {
            display: grid;
            grid-template-columns: 1.5fr 1fr 1fr 1fr;
            gap: 40px;
            margin-bottom: 32px;
        }
        .site-footer .footer-brand .logo-text {
            font-size: 1.2rem;
            font-weight: 700;
            color: #fff;
            display: flex;
            align-items: center;
            gap: 8px;
            margin-bottom: 12px;
        }
        .site-footer .footer-brand .logo-text i {
            color: var(--primary-light);
        }
        .site-footer .footer-brand p {
            color: var(--text-muted);
            font-size: 0.9rem;
            max-width: 300px;
            line-height: 1.6;
        }
        .site-footer .footer-col h5 {
            font-size: 0.95rem;
            color: #fff;
            margin-bottom: 16px;
            font-weight: 600;
        }
        .site-footer .footer-col a {
            display: block;
            color: var(--text-muted);
            font-size: 0.88rem;
            padding: 4px 0;
            transition: color var(--transition);
        }
        .site-footer .footer-col a i {
            margin-right: 6px;
            font-size: 0.7rem;
            color: var(--text-muted);
            transition: color var(--transition);
        }
        .site-footer .footer-col a:hover {
            color: #fff;
        }
        .site-footer .footer-col a:hover i {
            color: var(--primary-light);
        }
        .site-footer .footer-bottom {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 12px;
            padding-top: 24px;
            border-top: 1px solid var(--border-color);
            font-size: 0.82rem;
            color: var(--text-muted);
        }
        .site-footer .footer-bottom a {
            color: var(--text-muted);
        }
        .site-footer .footer-bottom a:hover {
            color: var(--primary-light);
        }

        /* ===== Not Found State ===== */
        .not-found-box {
            text-align: center;
            padding: 80px 20px;
        }
        .not-found-box i {
            font-size: 4rem;
            color: var(--text-muted);
            margin-bottom: 20px;
        }
        .not-found-box h2 {
            font-size: 1.8rem;
            margin-bottom: 12px;
        }
        .not-found-box p {
            color: var(--text-muted);
            margin-bottom: 24px;
        }
        .not-found-box a {
            display: inline-block;
            padding: 12px 32px;
            border-radius: 50px;
            background: linear-gradient(135deg, var(--primary), var(--secondary));
            color: #fff;
            font-weight: 600;
            transition: all var(--transition);
        }
        .not-found-box a:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 24px rgba(108, 92, 231, 0.3);
        }

        /* ===== Responsive ===== */
        @media (max-width: 1024px) {
            .article-layout {
                grid-template-columns: 1fr;
            }
            .article-sidebar {
                display: grid;
                grid-template-columns: 1fr 1fr;
                gap: 24px;
            }
            .related-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            .site-footer .footer-grid {
                grid-template-columns: 1fr 1fr;
                gap: 32px;
            }
        }

        @media (max-width: 768px) {
            .sidebar {
                transform: translateX(-100%);
            }
            .sidebar.open {
                transform: translateX(0);
            }
            .mobile-header {
                display: flex;
            }
            .mobile-overlay.open {
                display: block;
            }
            .main-wrapper {
                margin-left: 0;
            }
            .article-hero {
                padding: 32px 0 28px;
            }
            .article-hero h1 {
                font-size: 1.8rem;
            }
            .article-layout {
                grid-template-columns: 1fr;
            }
            .article-sidebar {
                grid-template-columns: 1fr;
            }
            .related-grid {
                grid-template-columns: 1fr;
            }
            .article-cta h2 {
                font-size: 1.4rem;
            }
            .site-footer .footer-grid {
                grid-template-columns: 1fr;
                gap: 24px;
            }
            .site-footer .footer-bottom {
                flex-direction: column;
                text-align: center;
            }
            .article-meta {
                gap: 12px;
                font-size: 0.82rem;
            }
            .article-share {
                flex-wrap: wrap;
            }
        }

        @media (max-width: 520px) {
            .container {
                padding: 0 16px;
            }
            .article-hero h1 {
                font-size: 1.5rem;
            }
            .article-body .content {
                font-size: 0.95rem;
            }
            .article-cta .btn-group {
                flex-direction: column;
                align-items: center;
            }
            .article-cta .btn-primary,
            .article-cta .btn-secondary {
                width: 100%;
                max-width: 280px;
                justify-content: center;
            }
            .related-card .card-img {
                height: 140px;
            }
            .sidebar-widget {
                padding: 16px;
            }
        }

        /* ===== Loading & Transitions ===== */
        .fade-in {
            animation: fadeIn 0.5s ease forwards;
        }
        @keyframes fadeIn {
            from {
                opacity: 0;
                transform: translateY(12px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

/* roulang page: category1 */
/* ===== Design Variables ===== */
    :root {
      --primary: #6c5ce7;
      --primary-light: #a29bfe;
      --primary-dark: #4a3db8;
      --secondary: #fd79a8;
      --accent: #00cec9;
      --accent-light: #81ecec;
      --bg-dark: #0a0a1a;
      --bg-card: #12122a;
      --bg-elevated: #1a1a3a;
      --bg-surface: #222246;
      --text-primary: #f0f0ff;
      --text-secondary: #b0b0d0;
      --text-muted: #7070a0;
      --border-color: #2a2a5a;
      --radius: 16px;
      --radius-sm: 10px;
      --radius-xs: 6px;
      --shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
      --shadow-sm: 0 4px 16px rgba(0, 0, 0, 0.3);
      --shadow-glow: 0 0 30px rgba(108, 92, 231, 0.15);
      --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
      --font-sans: 'Segoe UI', system-ui, -apple-system, sans-serif;
      --sidebar-width: 220px;
      --header-height: 0px;
    }

    /* ===== Reset & Base ===== */
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; font-size: 16px; }
    body {
      font-family: var(--font-sans);
      background: var(--bg-dark);
      color: var(--text-primary);
      line-height: 1.7;
      min-height: 100vh;
      display: flex;
    }
    a { color: var(--primary-light); text-decoration: none; transition: color var(--transition); }
    a:hover { color: #fff; }
    img { max-width: 100%; height: auto; display: block; }
    button, input, textarea { font-family: inherit; font-size: 1rem; }
    ul, ol { list-style: none; }
    h1, h2, h3, h4, h5, h6 { line-height: 1.3; font-weight: 700; }

    /* ===== Container ===== */
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* ===== App Shell Layout ===== */
    .app-shell {
      display: flex;
      width: 100%;
      min-height: 100vh;
    }

    /* ===== Sidebar ===== */
    .sidebar {
      position: fixed;
      top: 0;
      left: 0;
      width: var(--sidebar-width);
      height: 100vh;
      background: var(--bg-card);
      border-right: 1px solid var(--border-color);
      display: flex;
      flex-direction: column;
      z-index: 1000;
      backdrop-filter: blur(16px);
      overflow-y: auto;
      transition: transform var(--transition);
    }
    .sidebar-brand {
      padding: 28px 20px 20px;
      border-bottom: 1px solid var(--border-color);
    }
    .sidebar-brand .logo-text {
      font-size: 1.4rem;
      font-weight: 800;
      color: #fff;
      display: flex;
      align-items: center;
      gap: 10px;
    }
    .sidebar-brand .logo-text i {
      color: var(--accent);
      font-size: 1.5rem;
    }
    .sidebar-brand .logo-sub {
      font-size: 0.75rem;
      color: var(--text-muted);
      margin-top: 4px;
      letter-spacing: 0.5px;
    }
    .sidebar-nav {
      flex: 1;
      padding: 16px 12px;
      display: flex;
      flex-direction: column;
      gap: 4px;
    }
    .sidebar-nav .nav-item {
      display: flex;
      align-items: center;
      gap: 12px;
      padding: 12px 16px;
      border-radius: var(--radius-sm);
      color: var(--text-secondary);
      font-weight: 500;
      font-size: 0.95rem;
      transition: all var(--transition);
      position: relative;
    }
    .sidebar-nav .nav-item i {
      width: 20px;
      text-align: center;
      font-size: 1.1rem;
      color: var(--text-muted);
      transition: color var(--transition);
    }
    .sidebar-nav .nav-item:hover {
      background: var(--bg-surface);
      color: #fff;
    }
    .sidebar-nav .nav-item:hover i {
      color: var(--primary-light);
    }
    .sidebar-nav .nav-item.active {
      background: rgba(108, 92, 231, 0.2);
      color: #fff;
      box-shadow: inset 3px 0 0 var(--primary);
    }
    .sidebar-nav .nav-item.active i {
      color: var(--primary-light);
    }
    .sidebar-footer {
      padding: 16px 20px 24px;
      border-top: 1px solid var(--border-color);
      font-size: 0.75rem;
      color: var(--text-muted);
      text-align: center;
    }

    /* ===== Main Content Area ===== */
    .main-content {
      margin-left: var(--sidebar-width);
      flex: 1;
      min-height: 100vh;
      display: flex;
      flex-direction: column;
    }

    /* ===== Mobile Header ===== */
    .mobile-header {
      display: none;
      position: sticky;
      top: 0;
      z-index: 999;
      background: var(--bg-card);
      border-bottom: 1px solid var(--border-color);
      padding: 12px 20px;
      align-items: center;
      justify-content: space-between;
      backdrop-filter: blur(12px);
    }
    .mobile-header .logo-text {
      font-size: 1.2rem;
      font-weight: 800;
      color: #fff;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .mobile-header .logo-text i { color: var(--accent); }
    .menu-toggle {
      background: none;
      border: none;
      color: var(--text-primary);
      font-size: 1.5rem;
      cursor: pointer;
      padding: 4px 8px;
      border-radius: var(--radius-xs);
      transition: background var(--transition);
    }
    .menu-toggle:hover { background: var(--bg-surface); }

    /* ===== Hero / Banner ===== */
    .category-banner {
      position: relative;
      min-height: 320px;
      display: flex;
      align-items: center;
      justify-content: center;
      text-align: center;
      padding: 80px 24px 60px;
      background: linear-gradient(135deg, rgba(10,10,26,0.85), rgba(30,20,60,0.9)), url('/assets/images/backpic/back-2.png') center center / cover no-repeat;
      border-bottom: 1px solid var(--border-color);
      overflow: hidden;
    }
    .category-banner::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      right: 0;
      height: 80px;
      background: linear-gradient(to top, var(--bg-dark), transparent);
    }
    .category-banner .banner-content {
      position: relative;
      z-index: 2;
      max-width: 800px;
    }
    .category-banner .banner-tag {
      display: inline-block;
      background: rgba(108, 92, 231, 0.25);
      color: var(--primary-light);
      padding: 6px 18px;
      border-radius: 50px;
      font-size: 0.85rem;
      font-weight: 600;
      letter-spacing: 0.5px;
      border: 1px solid rgba(108, 92, 231, 0.3);
      margin-bottom: 16px;
    }
    .category-banner h1 {
      font-size: 3rem;
      font-weight: 900;
      color: #fff;
      margin-bottom: 16px;
      text-shadow: 0 4px 20px rgba(0,0,0,0.5);
    }
    .category-banner h1 i { color: var(--accent); }
    .category-banner p {
      font-size: 1.15rem;
      color: var(--text-secondary);
      max-width: 600px;
      margin: 0 auto;
      line-height: 1.8;
    }
    .banner-search {
      margin-top: 28px;
      display: flex;
      max-width: 480px;
      margin-left: auto;
      margin-right: auto;
      background: var(--bg-card);
      border-radius: 50px;
      border: 1px solid var(--border-color);
      overflow: hidden;
      transition: border-color var(--transition);
    }
    .banner-search:focus-within {
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(108, 92, 231, 0.2);
    }
    .banner-search input {
      flex: 1;
      padding: 14px 20px;
      background: transparent;
      border: none;
      color: var(--text-primary);
      outline: none;
      font-size: 0.95rem;
    }
    .banner-search input::placeholder { color: var(--text-muted); }
    .banner-search button {
      padding: 14px 24px;
      background: var(--primary);
      border: none;
      color: #fff;
      cursor: pointer;
      font-size: 1rem;
      transition: background var(--transition);
    }
    .banner-search button:hover { background: var(--primary-dark); }

    /* ===== Section Common ===== */
    .section {
      padding: 64px 0;
    }
    .section-header {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-header h2 {
      font-size: 2.2rem;
      font-weight: 800;
      color: #fff;
      margin-bottom: 12px;
    }
    .section-header h2 i { color: var(--accent); }
    .section-header p {
      color: var(--text-secondary);
      font-size: 1.05rem;
      max-width: 560px;
      margin: 0 auto;
    }
    .section-divider {
      width: 60px;
      height: 3px;
      background: linear-gradient(90deg, var(--primary), var(--accent));
      border-radius: 3px;
      margin: 16px auto 0;
    }

    /* ===== Topic Cards Grid ===== */
    .topic-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .topic-card {
      background: var(--bg-card);
      border-radius: var(--radius);
      overflow: hidden;
      border: 1px solid var(--border-color);
      transition: all var(--transition);
      cursor: default;
    }
    .topic-card:hover {
      transform: translateY(-6px);
      border-color: rgba(108, 92, 231, 0.3);
      box-shadow: var(--shadow), var(--shadow-glow);
    }
    .topic-card .card-img {
      width: 100%;
      height: 200px;
      object-fit: cover;
      display: block;
      transition: transform 0.5s ease;
    }
    .topic-card:hover .card-img {
      transform: scale(1.05);
    }
    .topic-card .card-body {
      padding: 24px 20px 20px;
      position: relative;
    }
    .topic-card .card-tag {
      display: inline-block;
      background: rgba(0, 206, 201, 0.15);
      color: var(--accent);
      font-size: 0.75rem;
      font-weight: 600;
      padding: 3px 12px;
      border-radius: 50px;
      margin-bottom: 10px;
      border: 1px solid rgba(0, 206, 201, 0.2);
    }
    .topic-card h3 {
      font-size: 1.2rem;
      font-weight: 700;
      color: #fff;
      margin-bottom: 8px;
    }
    .topic-card .card-desc {
      color: var(--text-secondary);
      font-size: 0.9rem;
      line-height: 1.6;
      margin-bottom: 16px;
    }
    .topic-card .card-meta {
      display: flex;
      align-items: center;
      gap: 16px;
      font-size: 0.8rem;
      color: var(--text-muted);
    }
    .topic-card .card-meta i { margin-right: 4px; }

    /* ===== Category Index ===== */
    .cat-index-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
    }
    .cat-index-item {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-sm);
      padding: 28px 20px;
      text-align: center;
      transition: all var(--transition);
      cursor: default;
    }
    .cat-index-item:hover {
      border-color: var(--primary);
      box-shadow: var(--shadow-sm);
      transform: translateY(-3px);
    }
    .cat-index-item .cat-icon {
      width: 56px;
      height: 56px;
      border-radius: 50%;
      background: rgba(108, 92, 231, 0.15);
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 14px;
      font-size: 1.5rem;
      color: var(--primary-light);
      transition: background var(--transition);
    }
    .cat-index-item:hover .cat-icon {
      background: rgba(108, 92, 231, 0.25);
    }
    .cat-index-item h4 {
      font-size: 1rem;
      font-weight: 700;
      color: #fff;
      margin-bottom: 6px;
    }
    .cat-index-item p {
      font-size: 0.8rem;
      color: var(--text-muted);
    }

    /* ===== Featured Content ===== */
    .featured-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
    }
    .featured-card {
      display: flex;
      background: var(--bg-card);
      border-radius: var(--radius);
      border: 1px solid var(--border-color);
      overflow: hidden;
      transition: all var(--transition);
    }
    .featured-card:hover {
      border-color: rgba(0, 206, 201, 0.3);
      box-shadow: var(--shadow-sm);
    }
    .featured-card .feat-img {
      width: 180px;
      min-height: 180px;
      object-fit: cover;
      flex-shrink: 0;
    }
    .featured-card .feat-body {
      padding: 20px 20px 18px;
      display: flex;
      flex-direction: column;
      justify-content: center;
    }
    .featured-card .feat-body .feat-tag {
      font-size: 0.7rem;
      color: var(--accent);
      font-weight: 600;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      margin-bottom: 6px;
    }
    .featured-card .feat-body h4 {
      font-size: 1.05rem;
      font-weight: 700;
      color: #fff;
      margin-bottom: 6px;
    }
    .featured-card .feat-body p {
      font-size: 0.85rem;
      color: var(--text-secondary);
      line-height: 1.5;
    }

    /* ===== Stats ===== */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    .stat-item {
      text-align: center;
      padding: 28px 16px;
      background: var(--bg-card);
      border-radius: var(--radius);
      border: 1px solid var(--border-color);
      transition: all var(--transition);
    }
    .stat-item:hover {
      border-color: var(--primary);
      box-shadow: var(--shadow-sm);
    }
    .stat-item .stat-number {
      font-size: 2.6rem;
      font-weight: 900;
      background: linear-gradient(135deg, var(--primary-light), var(--accent));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .stat-item .stat-label {
      font-size: 0.9rem;
      color: var(--text-secondary);
      margin-top: 6px;
    }

    /* ===== FAQ ===== */
    .faq-list {
      max-width: 780px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 12px;
    }
    .faq-item {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-sm);
      overflow: hidden;
      transition: border-color var(--transition);
    }
    .faq-item:hover {
      border-color: rgba(108, 92, 231, 0.3);
    }
    .faq-question {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 18px 22px;
      cursor: pointer;
      font-weight: 600;
      color: #fff;
      font-size: 1rem;
      transition: background var(--transition);
      user-select: none;
    }
    .faq-question:hover { background: var(--bg-surface); }
    .faq-question i { color: var(--primary-light); transition: transform var(--transition); }
    .faq-question.active i { transform: rotate(180deg); }
    .faq-answer {
      padding: 0 22px 18px;
      color: var(--text-secondary);
      font-size: 0.92rem;
      line-height: 1.7;
      display: none;
    }
    .faq-answer.show { display: block; }

    /* ===== CTA ===== */
    .cta-section {
      background: linear-gradient(135deg, rgba(108, 92, 231, 0.12), rgba(0, 206, 201, 0.08)), url('/assets/images/backpic/back-3.png') center center / cover no-repeat;
      border-top: 1px solid var(--border-color);
      border-bottom: 1px solid var(--border-color);
      text-align: center;
      padding: 72px 24px;
    }
    .cta-section h2 {
      font-size: 2rem;
      font-weight: 800;
      color: #fff;
      margin-bottom: 12px;
    }
    .cta-section p {
      color: var(--text-secondary);
      font-size: 1.05rem;
      max-width: 520px;
      margin: 0 auto 28px;
    }
    .btn-group {
      display: flex;
      gap: 16px;
      justify-content: center;
      flex-wrap: wrap;
    }
    .btn {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      padding: 14px 32px;
      border-radius: 50px;
      font-weight: 600;
      font-size: 0.95rem;
      border: none;
      cursor: pointer;
      transition: all var(--transition);
    }
    .btn-primary {
      background: var(--primary);
      color: #fff;
      box-shadow: 0 4px 16px rgba(108, 92, 231, 0.3);
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: translateY(-2px);
      box-shadow: 0 8px 24px rgba(108, 92, 231, 0.4);
    }
    .btn-outline {
      background: transparent;
      color: var(--text-primary);
      border: 1px solid var(--border-color);
    }
    .btn-outline:hover {
      border-color: var(--primary-light);
      color: #fff;
      background: rgba(108, 92, 231, 0.1);
    }

    /* ===== Footer (shared) ===== */
    .site-footer {
      background: var(--bg-card);
      border-top: 1px solid var(--border-color);
      padding: 52px 0 0;
      margin-top: auto;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
      padding-bottom: 36px;
    }
    .footer-brand .logo-text {
      font-size: 1.3rem;
      font-weight: 800;
      color: #fff;
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 12px;
    }
    .footer-brand .logo-text i { color: var(--accent); }
    .footer-brand p {
      color: var(--text-secondary);
      font-size: 0.9rem;
      line-height: 1.7;
      max-width: 320px;
    }
    .footer-col h5 {
      font-size: 0.95rem;
      font-weight: 700;
      color: #fff;
      margin-bottom: 16px;
      letter-spacing: 0.3px;
    }
    .footer-col a {
      display: block;
      color: var(--text-secondary);
      font-size: 0.9rem;
      padding: 5px 0;
      transition: all var(--transition);
    }
    .footer-col a i { margin-right: 6px; font-size: 0.7rem; color: var(--text-muted); }
    .footer-col a:hover { color: #fff; padding-left: 4px; }
    .footer-col a:hover i { color: var(--primary-light); }
    .footer-bottom {
      border-top: 1px solid var(--border-color);
      padding: 20px 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 8px;
      font-size: 0.82rem;
      color: var(--text-muted);
    }
    .footer-bottom a { color: var(--text-secondary); }
    .footer-bottom a:hover { color: #fff; }

    /* ===== Responsive ===== */
    @media (max-width: 1024px) {
      .topic-grid { grid-template-columns: repeat(2, 1fr); }
      .cat-index-grid { grid-template-columns: repeat(2, 1fr); }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }

    @media (max-width: 768px) {
      .sidebar { transform: translateX(-100%); }
      .sidebar.open { transform: translateX(0); }
      .main-content { margin-left: 0; }
      .mobile-header { display: flex; }
      .category-banner { min-height: 240px; padding: 60px 20px 40px; }
      .category-banner h1 { font-size: 2rem; }
      .category-banner p { font-size: 1rem; }
      .topic-grid { grid-template-columns: 1fr; }
      .featured-grid { grid-template-columns: 1fr; }
      .featured-card { flex-direction: column; }
      .featured-card .feat-img { width: 100%; height: 180px; }
      .stats-grid { grid-template-columns: repeat(2, 1fr); }
      .cat-index-grid { grid-template-columns: repeat(2, 1fr); }
      .footer-grid { grid-template-columns: 1fr; gap: 24px; }
      .footer-bottom { flex-direction: column; text-align: center; }
      .section { padding: 40px 0; }
      .section-header h2 { font-size: 1.6rem; }
      .btn-group { flex-direction: column; align-items: center; }
    }

    @media (max-width: 520px) {
      .category-banner h1 { font-size: 1.6rem; }
      .stats-grid { grid-template-columns: 1fr 1fr; gap: 12px; }
      .stat-item .stat-number { font-size: 2rem; }
      .cat-index-grid { grid-template-columns: 1fr; }
      .banner-search { flex-direction: column; border-radius: var(--radius-sm); }
      .banner-search input { text-align: center; }
      .banner-search button { width: 100%; }
      .container { padding: 0 16px; }
    }

    /* ===== Overlay for mobile ===== */
    .sidebar-overlay {
      display: none;
      position: fixed;
      inset: 0;
      background: rgba(0,0,0,0.5);
      z-index: 999;
    }
    .sidebar-overlay.show { display: block; }

    /* ===== Misc utilities ===== */
    .text-accent { color: var(--accent); }
    .text-primary-light { color: var(--primary-light); }
    .mb-8 { margin-bottom: 8px; }
    .mb-16 { margin-bottom: 16px; }
    .mt-16 { margin-top: 16px; }

/* roulang page: category2 */
/* ===== 设计变量 ===== */
        :root {
            --primary: #7c3aed;
            --primary-light: #a78bfa;
            --primary-dark: #5b21b6;
            --accent: #06b6d4;
            --accent-light: #67e8f9;
            --deep-bg: #0b0d1a;
            --panel-bg: #11162b;
            --card-bg: #161d35;
            --surface: #1a2240;
            --border-color: #2a3470;
            --text-primary: #f1f5f9;
            --text-secondary: #a5b4e0;
            --text-muted: #6b7db3;
            --radius: 16px;
            --radius-sm: 10px;
            --radius-lg: 24px;
            --shadow: 0 8px 32px rgba(0, 0, 0, 0.6);
            --shadow-sm: 0 4px 16px rgba(0, 0, 0, 0.4);
            --glow: 0 0 30px rgba(124, 58, 237, 0.25);
            --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            --sidebar-width: 240px;
            --font-sans: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
        }

        /* ===== Reset & Base ===== */
        *,
        *::before,
        *::after {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }
        html {
            scroll-behavior: smooth;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }
        body {
            font-family: var(--font-sans);
            background: var(--deep-bg);
            color: var(--text-primary);
            line-height: 1.7;
            font-size: 16px;
            min-height: 100vh;
            display: flex;
        }
        a {
            color: var(--primary-light);
            text-decoration: none;
            transition: color var(--transition);
        }
        a:hover {
            color: var(--accent-light);
        }
        img {
            max-width: 100%;
            height: auto;
            display: block;
        }
        button,
        input,
        textarea {
            font-family: inherit;
            font-size: inherit;
            border: none;
            outline: none;
            background: transparent;
            color: inherit;
        }
        ul,
        ol {
            list-style: none;
        }
        h1,
        h2,
        h3,
        h4,
        h5,
        h6 {
            font-weight: 700;
            line-height: 1.3;
            color: var(--text-primary);
        }
        h1 {
            font-size: 2.8rem;
        }
        h2 {
            font-size: 2rem;
        }
        h3 {
            font-size: 1.4rem;
        }
        h4 {
            font-size: 1.1rem;
        }
        p {
            color: var(--text-secondary);
            margin-bottom: 1rem;
        }

        /* ===== Container ===== */
        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 24px;
        }

        /* ===== Sidebar / App Shell ===== */
        .app-shell {
            display: flex;
            width: 100%;
            min-height: 100vh;
        }
        .sidebar {
            width: var(--sidebar-width);
            background: var(--panel-bg);
            border-right: 1px solid var(--border-color);
            display: flex;
            flex-direction: column;
            position: fixed;
            top: 0;
            left: 0;
            bottom: 0;
            z-index: 1000;
            overflow-y: auto;
            padding: 28px 16px 20px;
            transition: transform var(--transition);
        }
        .sidebar-logo {
            display: flex;
            align-items: center;
            gap: 12px;
            padding: 0 12px 28px;
            border-bottom: 1px solid var(--border-color);
            margin-bottom: 24px;
            font-size: 1.4rem;
            font-weight: 800;
            color: var(--text-primary);
        }
        .sidebar-logo i {
            color: var(--accent);
            font-size: 1.6rem;
        }
        .sidebar-logo span {
            background: linear-gradient(135deg, var(--primary-light), var(--accent-light));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }
        .sidebar-nav {
            display: flex;
            flex-direction: column;
            gap: 6px;
            flex: 1;
        }
        .sidebar-nav .nav-item {
            display: flex;
            align-items: center;
            gap: 14px;
            padding: 12px 16px;
            border-radius: var(--radius-sm);
            font-size: 1rem;
            font-weight: 500;
            color: var(--text-secondary);
            transition: all var(--transition);
            position: relative;
        }
        .sidebar-nav .nav-item i {
            width: 20px;
            text-align: center;
            font-size: 1.1rem;
            color: var(--text-muted);
            transition: color var(--transition);
        }
        .sidebar-nav .nav-item:hover {
            background: rgba(124, 58, 237, 0.12);
            color: var(--text-primary);
        }
        .sidebar-nav .nav-item:hover i {
            color: var(--primary-light);
        }
        .sidebar-nav .nav-item.active {
            background: rgba(124, 58, 237, 0.2);
            color: var(--text-primary);
            box-shadow: inset 3px 0 0 var(--primary);
        }
        .sidebar-nav .nav-item.active i {
            color: var(--primary-light);
        }
        .sidebar-footer {
            padding-top: 20px;
            border-top: 1px solid var(--border-color);
            margin-top: auto;
            font-size: 0.8rem;
            color: var(--text-muted);
            text-align: center;
        }

        /* ===== Main Content ===== */
        .main-content {
            margin-left: var(--sidebar-width);
            flex: 1;
            min-height: 100vh;
            display: flex;
            flex-direction: column;
        }

        /* ===== Mobile Header ===== */
        .mobile-header {
            display: none;
            background: var(--panel-bg);
            border-bottom: 1px solid var(--border-color);
            padding: 12px 20px;
            align-items: center;
            justify-content: space-between;
            position: sticky;
            top: 0;
            z-index: 999;
        }
        .mobile-header .logo-text {
            font-size: 1.2rem;
            font-weight: 800;
            display: flex;
            align-items: center;
            gap: 8px;
        }
        .mobile-header .logo-text i {
            color: var(--accent);
        }
        .mobile-header .logo-text span {
            background: linear-gradient(135deg, var(--primary-light), var(--accent-light));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }
        .menu-toggle {
            background: none;
            border: none;
            color: var(--text-primary);
            font-size: 1.6rem;
            cursor: pointer;
            padding: 4px 8px;
            border-radius: 8px;
            transition: background var(--transition);
        }
        .menu-toggle:hover {
            background: rgba(255, 255, 255, 0.08);
        }

        /* ===== Hero / Banner ===== */
        .page-banner {
            position: relative;
            padding: 80px 0 60px;
            background: linear-gradient(135deg, rgba(11, 13, 26, 0.92), rgba(22, 29, 53, 0.88)), url('/assets/images/backpic/back-2.png') center center / cover no-repeat;
            border-bottom: 1px solid var(--border-color);
        }
        .page-banner::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            right: 0;
            height: 80px;
            background: linear-gradient(to top, var(--deep-bg), transparent);
            pointer-events: none;
        }
        .page-banner .container {
            position: relative;
            z-index: 2;
        }
        .page-banner h1 {
            font-size: 2.6rem;
            margin-bottom: 16px;
            display: flex;
            align-items: center;
            gap: 14px;
        }
        .page-banner h1 i {
            color: var(--accent);
            font-size: 2.2rem;
        }
        .page-banner .breadcrumb {
            display: flex;
            gap: 10px;
            font-size: 0.9rem;
            color: var(--text-muted);
            margin-bottom: 12px;
            flex-wrap: wrap;
        }
        .page-banner .breadcrumb a {
            color: var(--text-muted);
        }
        .page-banner .breadcrumb a:hover {
            color: var(--primary-light);
        }
        .page-banner .breadcrumb .sep {
            color: var(--text-muted);
        }
        .page-banner p {
            font-size: 1.15rem;
            max-width: 720px;
            color: var(--text-secondary);
        }
        .banner-stats {
            display: flex;
            gap: 40px;
            margin-top: 32px;
            flex-wrap: wrap;
        }
        .banner-stats .stat-item {
            display: flex;
            flex-direction: column;
        }
        .banner-stats .stat-number {
            font-size: 2rem;
            font-weight: 800;
            color: var(--text-primary);
            line-height: 1.2;
        }
        .banner-stats .stat-number i {
            color: var(--accent);
            font-size: 1.6rem;
            margin-right: 6px;
        }
        .banner-stats .stat-label {
            font-size: 0.85rem;
            color: var(--text-muted);
        }

        /* ===== Section共用 ===== */
        .section {
            padding: 70px 0;
        }
        .section-header {
            text-align: center;
            margin-bottom: 48px;
        }
        .section-header h2 {
            margin-bottom: 12px;
            position: relative;
            display: inline-block;
        }
        .section-header h2::after {
            content: '';
            display: block;
            width: 60px;
            height: 3px;
            background: linear-gradient(90deg, var(--primary), var(--accent));
            border-radius: 4px;
            margin: 12px auto 0;
        }
        .section-header p {
            max-width: 620px;
            margin: 0 auto;
            color: var(--text-muted);
            font-size: 1.05rem;
        }
        .section-header.text-left {
            text-align: left;
        }
        .section-header.text-left h2::after {
            margin: 12px 0 0;
        }

        /* ===== 资源分类标签 ===== */
        .resource-tabs {
            display: flex;
            gap: 12px;
            flex-wrap: wrap;
            margin-bottom: 40px;
            justify-content: center;
        }
        .resource-tabs .tab-btn {
            padding: 10px 24px;
            border-radius: 50px;
            background: var(--surface);
            border: 1px solid var(--border-color);
            color: var(--text-secondary);
            font-weight: 500;
            font-size: 0.95rem;
            cursor: pointer;
            transition: all var(--transition);
        }
        .resource-tabs .tab-btn:hover {
            border-color: var(--primary);
            color: var(--text-primary);
            background: rgba(124, 58, 237, 0.1);
        }
        .resource-tabs .tab-btn.active {
            background: var(--primary);
            border-color: var(--primary);
            color: #fff;
            box-shadow: var(--glow);
        }

        /* ===== 资源卡片网格 ===== */
        .resource-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 24px;
        }
        .resource-card {
            background: var(--card-bg);
            border-radius: var(--radius);
            border: 1px solid var(--border-color);
            padding: 28px 24px 24px;
            transition: all var(--transition);
            position: relative;
            overflow: hidden;
        }
        .resource-card::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 3px;
            background: linear-gradient(90deg, var(--primary), var(--accent));
            opacity: 0;
            transition: opacity var(--transition);
        }
        .resource-card:hover {
            transform: translateY(-4px);
            border-color: var(--primary);
            box-shadow: var(--shadow);
        }
        .resource-card:hover::before {
            opacity: 1;
        }
        .resource-card .card-icon {
            width: 48px;
            height: 48px;
            border-radius: 12px;
            background: rgba(124, 58, 237, 0.15);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.4rem;
            color: var(--primary-light);
            margin-bottom: 16px;
        }
        .resource-card h3 {
            font-size: 1.15rem;
            margin-bottom: 8px;
        }
        .resource-card p {
            font-size: 0.92rem;
            color: var(--text-muted);
            margin-bottom: 16px;
            line-height: 1.6;
        }
        .resource-card .card-meta {
            display: flex;
            flex-wrap: wrap;
            gap: 12px;
            font-size: 0.82rem;
            color: var(--text-muted);
            border-top: 1px solid var(--border-color);
            padding-top: 14px;
            margin-top: auto;
        }
        .resource-card .card-meta span {
            display: flex;
            align-items: center;
            gap: 6px;
        }
        .resource-card .card-meta i {
            color: var(--accent);
        }
        .resource-card .badge {
            display: inline-block;
            padding: 2px 12px;
            border-radius: 50px;
            font-size: 0.75rem;
            font-weight: 600;
            background: rgba(6, 182, 212, 0.15);
            color: var(--accent-light);
            margin-bottom: 12px;
        }
        .resource-card .badge.hot {
            background: rgba(239, 68, 68, 0.15);
            color: #f87171;
        }
        .resource-card .badge.new {
            background: rgba(34, 197, 94, 0.15);
            color: #4ade80;
        }

        /* ===== 特色数据集板块 ===== */
        .dataset-showcase {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 28px;
            align-items: center;
        }
        .dataset-showcase .showcase-image {
            border-radius: var(--radius);
            overflow: hidden;
            box-shadow: var(--shadow);
            border: 1px solid var(--border-color);
            background: var(--card-bg);
        }
        .dataset-showcase .showcase-image img {
            width: 100%;
            height: 340px;
            object-fit: cover;
            display: block;
        }
        .dataset-showcase .showcase-content h2 {
            margin-bottom: 16px;
        }
        .dataset-showcase .showcase-content p {
            margin-bottom: 20px;
            font-size: 1.05rem;
        }
        .dataset-features {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 12px;
        }
        .dataset-features li {
            display: flex;
            align-items: center;
            gap: 10px;
            font-size: 0.95rem;
            color: var(--text-secondary);
        }
        .dataset-features li i {
            color: var(--accent);
            font-size: 1rem;
            width: 20px;
        }

        /* ===== 工具列表 ===== */
        .tools-list {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 20px;
        }
        .tool-item {
            background: var(--card-bg);
            border-radius: var(--radius-sm);
            border: 1px solid var(--border-color);
            padding: 20px 18px;
            text-align: center;
            transition: all var(--transition);
        }
        .tool-item:hover {
            border-color: var(--primary);
            transform: translateY(-3px);
            box-shadow: var(--shadow-sm);
        }
        .tool-item .tool-icon {
            font-size: 2rem;
            color: var(--primary-light);
            margin-bottom: 12px;
        }
        .tool-item h4 {
            font-size: 1rem;
            margin-bottom: 4px;
        }
        .tool-item p {
            font-size: 0.82rem;
            color: var(--text-muted);
            margin-bottom: 0;
        }

        /* ===== 学习资源 ===== */
        .learning-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 24px;
        }
        .learn-card {
            background: var(--card-bg);
            border-radius: var(--radius);
            border: 1px solid var(--border-color);
            overflow: hidden;
            transition: all var(--transition);
        }
        .learn-card:hover {
            transform: translateY(-4px);
            border-color: var(--primary);
            box-shadow: var(--shadow);
        }
        .learn-card .learn-img {
            height: 180px;
            overflow: hidden;
        }
        .learn-card .learn-img img {
            width: 100%;
            height: 100%;
            object-fit: cover;
            transition: transform 0.5s ease;
        }
        .learn-card:hover .learn-img img {
            transform: scale(1.06);
        }
        .learn-card .learn-body {
            padding: 20px 22px 22px;
        }
        .learn-card .learn-body .badge {
            display: inline-block;
            padding: 2px 12px;
            border-radius: 50px;
            font-size: 0.75rem;
            font-weight: 600;
            background: rgba(124, 58, 237, 0.15);
            color: var(--primary-light);
            margin-bottom: 10px;
        }
        .learn-card .learn-body h3 {
            font-size: 1.1rem;
            margin-bottom: 8px;
        }
        .learn-card .learn-body p {
            font-size: 0.9rem;
            color: var(--text-muted);
            margin-bottom: 14px;
        }
        .learn-card .learn-footer {
            display: flex;
            justify-content: space-between;
            align-items: center;
            font-size: 0.85rem;
            color: var(--text-muted);
            border-top: 1px solid var(--border-color);
            padding-top: 14px;
        }
        .learn-card .learn-footer a {
            color: var(--primary-light);
            font-weight: 500;
        }
        .learn-card .learn-footer a:hover {
            color: var(--accent-light);
        }

        /* ===== CTA ===== */
        .cta-block {
            background: linear-gradient(135deg, rgba(124, 58, 237, 0.12), rgba(6, 182, 212, 0.08));
            border-radius: var(--radius-lg);
            border: 1px solid var(--border-color);
            padding: 56px 48px;
            text-align: center;
            position: relative;
            overflow: hidden;
        }
        .cta-block::before {
            content: '';
            position: absolute;
            top: -50%;
            right: -20%;
            width: 400px;
            height: 400px;
            background: radial-gradient(circle, rgba(124, 58, 237, 0.08), transparent 70%);
            pointer-events: none;
        }
        .cta-block h2 {
            font-size: 1.8rem;
            margin-bottom: 12px;
        }
        .cta-block p {
            max-width: 560px;
            margin: 0 auto 28px;
            font-size: 1.05rem;
        }
        .btn-group {
            display: flex;
            gap: 16px;
            justify-content: center;
            flex-wrap: wrap;
        }
        .btn {
            display: inline-flex;
            align-items: center;
            gap: 10px;
            padding: 14px 32px;
            border-radius: 50px;
            font-weight: 600;
            font-size: 1rem;
            transition: all var(--transition);
            cursor: pointer;
            border: none;
            line-height: 1.2;
        }
        .btn-primary {
            background: linear-gradient(135deg, var(--primary), var(--primary-dark));
            color: #fff;
            box-shadow: 0 4px 20px rgba(124, 58, 237, 0.35);
        }
        .btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 32px rgba(124, 58, 237, 0.5);
            color: #fff;
        }
        .btn-outline {
            background: transparent;
            border: 1px solid var(--border-color);
            color: var(--text-primary);
        }
        .btn-outline:hover {
            border-color: var(--primary);
            background: rgba(124, 58, 237, 0.08);
            transform: translateY(-2px);
        }

        /* ===== FAQ ===== */
        .faq-grid {
            max-width: 800px;
            margin: 0 auto;
            display: flex;
            flex-direction: column;
            gap: 12px;
        }
        .faq-item {
            background: var(--card-bg);
            border-radius: var(--radius-sm);
            border: 1px solid var(--border-color);
            overflow: hidden;
            transition: border-color var(--transition);
        }
        .faq-item:hover {
            border-color: var(--primary);
        }
        .faq-question {
            padding: 18px 22px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            cursor: pointer;
            font-weight: 600;
            font-size: 1rem;
            color: var(--text-primary);
            gap: 16px;
            user-select: none;
        }
        .faq-question i {
            color: var(--primary-light);
            transition: transform var(--transition);
            flex-shrink: 0;
        }
        .faq-item.open .faq-question i {
            transform: rotate(180deg);
        }
        .faq-answer {
            padding: 0 22px 18px;
            color: var(--text-secondary);
            font-size: 0.95rem;
            line-height: 1.7;
            display: none;
        }
        .faq-item.open .faq-answer {
            display: block;
        }

        /* ===== Footer (共用) ===== */
        .site-footer {
            background: var(--panel-bg);
            border-top: 1px solid var(--border-color);
            padding: 56px 0 24px;
            margin-top: 40px;
        }
        .footer-grid {
            display: grid;
            grid-template-columns: 2fr 1fr 1fr 1fr;
            gap: 40px;
            margin-bottom: 40px;
        }
        .footer-brand .logo-text {
            font-size: 1.3rem;
            font-weight: 800;
            display: flex;
            align-items: center;
            gap: 10px;
            margin-bottom: 14px;
        }
        .footer-brand .logo-text i {
            color: var(--accent);
        }
        .footer-brand .logo-text span {
            background: linear-gradient(135deg, var(--primary-light), var(--accent-light));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }
        .footer-brand p {
            font-size: 0.9rem;
            color: var(--text-muted);
            max-width: 320px;
            line-height: 1.7;
        }
        .footer-col h5 {
            font-size: 1rem;
            font-weight: 700;
            margin-bottom: 18px;
            color: var(--text-primary);
        }
        .footer-col a {
            display: block;
            padding: 4px 0;
            font-size: 0.9rem;
            color: var(--text-muted);
            transition: color var(--transition), padding-left var(--transition);
        }
        .footer-col a i {
            margin-right: 6px;
            font-size: 0.7rem;
            color: var(--text-muted);
        }
        .footer-col a:hover {
            color: var(--primary-light);
            padding-left: 4px;
        }
        .footer-bottom {
            border-top: 1px solid var(--border-color);
            padding-top: 20px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 12px;
            font-size: 0.85rem;
            color: var(--text-muted);
        }
        .footer-bottom a {
            color: var(--text-muted);
        }
        .footer-bottom a:hover {
            color: var(--primary-light);
        }

        /* ===== 响应式 ===== */
        @media (max-width: 1024px) {
            .resource-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            .tools-list {
                grid-template-columns: repeat(2, 1fr);
            }
            .learning-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            .dataset-showcase {
                grid-template-columns: 1fr;
            }
            .dataset-showcase .showcase-image img {
                height: 260px;
            }
            .footer-grid {
                grid-template-columns: 1fr 1fr;
                gap: 32px;
            }
        }

        @media (max-width: 768px) {
            body {
                flex-direction: column;
            }
            .sidebar {
                transform: translateX(-100%);
                width: 280px;
            }
            .sidebar.open {
                transform: translateX(0);
            }
            .main-content {
                margin-left: 0;
            }
            .mobile-header {
                display: flex;
            }
            .page-banner {
                padding: 60px 0 50px;
            }
            .page-banner h1 {
                font-size: 2rem;
            }
            .page-banner p {
                font-size: 1rem;
            }
            .banner-stats {
                gap: 24px;
            }
            .banner-stats .stat-number {
                font-size: 1.6rem;
            }
            .section {
                padding: 50px 0;
            }
            .section-header h2 {
                font-size: 1.6rem;
            }
            .resource-grid {
                grid-template-columns: 1fr;
            }
            .tools-list {
                grid-template-columns: 1fr 1fr;
            }
            .learning-grid {
                grid-template-columns: 1fr;
            }
            .dataset-showcase .showcase-content h2 {
                font-size: 1.5rem;
            }
            .dataset-features {
                grid-template-columns: 1fr;
            }
            .cta-block {
                padding: 40px 24px;
            }
            .cta-block h2 {
                font-size: 1.4rem;
            }
            .btn {
                padding: 12px 24px;
                font-size: 0.95rem;
            }
            .footer-grid {
                grid-template-columns: 1fr;
                gap: 24px;
            }
            .footer-bottom {
                flex-direction: column;
                text-align: center;
            }
            .resource-tabs .tab-btn {
                padding: 8px 18px;
                font-size: 0.85rem;
            }
        }

        @media (max-width: 520px) {
            .page-banner h1 {
                font-size: 1.6rem;
            }
            .page-banner h1 i {
                font-size: 1.4rem;
            }
            .banner-stats {
                flex-direction: column;
                gap: 16px;
            }
            .tools-list {
                grid-template-columns: 1fr;
            }
            .btn-group {
                flex-direction: column;
                align-items: stretch;
            }
            .btn {
                justify-content: center;
            }
            .container {
                padding: 0 16px;
            }
            .section {
                padding: 40px 0;
            }
            .resource-card {
                padding: 20px 18px;
            }
            .faq-question {
                font-size: 0.95rem;
                padding: 14px 16px;
            }
            .faq-answer {
                padding: 0 16px 14px;
                font-size: 0.9rem;
            }
        }

        /* ===== 覆盖层 ===== */
        .sidebar-overlay {
            display: none;
            position: fixed;
            inset: 0;
            background: rgba(0, 0, 0, 0.6);
            z-index: 999;
        }
        .sidebar-overlay.show {
            display: block;
        }

        /* ===== 动画 ===== */
        @keyframes fadeInUp {
            from {
                opacity: 0;
                transform: translateY(20px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }
        .fade-in {
            animation: fadeInUp 0.6s ease both;
        }
        .delay-1 {
            animation-delay: 0.1s;
        }
        .delay-2 {
            animation-delay: 0.2s;
        }
        .delay-3 {
            animation-delay: 0.3s;
        }
        .delay-4 {
            animation-delay: 0.4s;
        }