/* ✦ AI 文章集萃 — Main Stylesheet */
/* Theme: Dark tech with cyan/purple/teal/amber accents */

:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #0f0f1a;
  --bg-card: #141420;
  --bg-card-hover: #1a1a2e;
  --border: #1e1e30;
  --border-light: #2a2a40;
  --text-primary: #e8e8f0;
  --text-secondary: #a0a0b8;
  --text-dim: #606078;

  --cyan: #00d4ff;
  --cyan-dim: rgba(0, 212, 255, 0.15);
  --purple: #a855f7;
  --purple-dim: rgba(168, 85, 247, 0.15);
  --teal: #2dd4bf;
  --teal-dim: rgba(45, 212, 191, 0.15);
  --amber: #f59e0b;
  --amber-dim: rgba(245, 158, 11, 0.15);

  --nav-height: 64px;
  --radius: 12px;
  --radius-sm: 8px;
  --transition: 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

/* ✦ Reset */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: var(--nav-height); }
body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3, h4 { font-family: 'Noto Serif SC', serif; font-weight: 600; }
a { color: var(--cyan); text-decoration: none; transition: color var(--transition); }
a:hover { color: #fff; }

/* ✦ Progress Bar */
#progress-bar {
  position: fixed; top: 0; left: 0; width: 100%; height: 2px; z-index: 1000;
  background: transparent;
}
#progress-fill {
  height: 100%; width: 0;
  background: linear-gradient(90deg, var(--cyan), var(--purple));
  transition: width 0.1s linear;
}

/* ✦ Nav */
#navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 999;
  height: var(--nav-height);
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), background var(--transition);
}
#navbar.scrolled {
  border-bottom-color: var(--border);
  background: rgba(10, 10, 15, 0.95);
}
.nav-inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; align-items: center;
  height: 100%; padding: 0 24px;
}
.nav-logo {
  display: flex; align-items: center; gap: 8px;
  color: var(--text-primary) !important; font-size: 18px; font-weight: 600;
  font-family: 'Noto Serif SC', serif;
}
.logo-icon { color: var(--cyan); font-size: 20px; }

.nav-links {
  display: flex; align-items: center; gap: 4px;
  margin-left: auto; list-style: none;
}
.nav-links a {
  padding: 8px 16px; border-radius: var(--radius-sm);
  color: var(--text-secondary); font-size: 14px; font-weight: 500;
  transition: all var(--transition); position: relative;
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
  background: var(--bg-card);
}

.nav-toggle { display: none; background: none; border: none; color: var(--text-primary); font-size: 24px; cursor: pointer; margin-left: auto; }

/* ✦ Hero */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex; align-items: center; justify-content: center;
  padding: 120px 24px 80px;
  overflow: hidden;
}
.hero-bg {
  position: absolute; inset: 0;
  background:
    radial-gradient(ellipse at 20% 50%, var(--cyan-dim) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 50%, var(--purple-dim) 0%, transparent 50%);
  opacity: 0.6;
}
.hero-content {
  position: relative; z-index: 1;
  text-align: center; max-width: 800px;
}
.hero-title {
  margin-bottom: 24px;
}
.title-line {
  display: block; font-size: clamp(40px, 8vw, 80px);
  font-weight: 700; line-height: 1.15;
  opacity: 0; transform: translateY(30px);
  animation: staggerIn 0.8s ease forwards;
}
.title-line:nth-child(1) { animation-delay: 0.2s; }
.title-line:nth-child(2) { animation-delay: 0.5s; }
.title-line.accent {
  background: linear-gradient(135deg, var(--cyan), var(--purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
@keyframes staggerIn {
  to { opacity: 1; transform: translateY(0); }
}

.hero-subtitle {
  font-size: clamp(16px, 2.5vw, 22px);
  color: var(--text-secondary);
  margin-bottom: 32px;
}
.hero-tags {
  display: flex; justify-content: center; gap: 12px; flex-wrap: wrap;
  margin-bottom: 48px;
}
.hero-tag {
  padding: 6px 18px; border-radius: 20px;
  font-size: 13px; font-weight: 500;
  border: 1px solid var(--tag-clr);
  color: var(--tag-clr);
  background: color-mix(in srgb, var(--tag-clr) 8%, transparent);
}
.hero-stats {
  display: flex; justify-content: center; align-items: center; gap: 24px;
}
.stat-item { text-align: center; }
.stat-num {
  display: block; font-size: 36px; font-weight: 700;
  font-family: 'JetBrains Mono', monospace;
  background: linear-gradient(135deg, var(--cyan), var(--purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.stat-label {
  font-size: 13px; color: var(--text-dim); margin-top: 2px;
}
.stat-divider {
  width: 1px; height: 40px; background: var(--border);
}

.scroll-indicator {
  position: absolute; bottom: 40px; left: 50%; transform: translateX(-50%);
  display: flex; flex-direction: column; align-items: center; gap: 8px;
  color: var(--text-dim); font-size: 12px; letter-spacing: 2px;
}
.scroll-arrow {
  animation: bounce 2s infinite; font-size: 20px;
}
@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(8px); }
}

/* ✦ Module Sections */
.module-section {
  padding: 100px 24px;
  position: relative;
}
.module-section::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 1px;
  background: linear-gradient(90deg, transparent, var(--border-light), transparent);
}
.module-section.alt {
  background: var(--bg-secondary);
}
.module-inner { max-width: 1000px; margin: 0 auto; }

.module-header { text-align: center; margin-bottom: 48px; }
.module-tag {
  display: inline-block; font-size: 13px; font-weight: 600; letter-spacing: 3px;
  color: var(--tag-color); margin-bottom: 12px;
  font-family: 'JetBrains Mono', monospace;
}
.module-header h2 {
  font-size: clamp(28px, 5vw, 42px); margin-bottom: 12px;
}
.module-desc {
  color: var(--text-secondary); font-size: 15px; max-width: 600px; margin: 0 auto;
}
.divider {
  width: 60px; height: 2px;
  background: var(--divider-clr, var(--cyan));
  margin: 16px auto; border-radius: 2px;
  opacity: 0.5;
}

.module-intro {
  max-width: 720px; margin: 0 auto 48px;
  text-align: center; color: var(--text-secondary);
  font-size: 15px; line-height: 2;
}
.module-intro strong { color: var(--text-primary); }

/* ✦ Article List */
.article-list {
  margin-bottom: 48px;
  border: 1px solid var(--border); border-radius: var(--radius);
  overflow: hidden;
}
.article-item {
  display: flex; align-items: flex-start; gap: 16px;
  padding: 20px 24px;
  border-bottom: 1px solid var(--border);
  transition: background var(--transition);
}
.article-item:last-child { border-bottom: none; }
.article-item:hover { background: var(--bg-card); }
.article-status {
  flex-shrink: 0;
  padding: 3px 10px; border-radius: 4px;
  font-size: 11px; font-weight: 600; letter-spacing: 1px;
  text-transform: uppercase;
}
.article-status.pending {
  background: var(--amber-dim);
  color: var(--amber);
}
.article-info h4 {
  font-size: 15px; margin-bottom: 2px; font-family: 'Inter', sans-serif;
  font-weight: 600;
}
.article-info p {
  font-size: 13px; color: var(--text-dim);
}
.article-item.coming-soon .article-info h4 { color: var(--text-dim); }

/* ✦ Topic Grid */
.topic-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 16px;
}
.topic-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: all var(--transition);
  cursor: default;
}
.topic-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-light);
  transform: translateY(-2px);
}
.topic-icon { font-size: 28px; margin-bottom: 12px; }
.topic-card h4 {
  font-size: 15px; margin-bottom: 6px;
  font-family: 'Inter', sans-serif;
}
.topic-card p { font-size: 13px; color: var(--text-dim); line-height: 1.5; }

/* ✦ News Feed */
.news-feed {
  margin-bottom: 48px;
}
.news-item {
  display: flex; gap: 16px;
  padding: 20px 0;
  border-bottom: 1px solid var(--border);
}
.news-item:first-child { padding-top: 0; }
.news-dot {
  flex-shrink: 0;
  width: 10px; height: 10px; border-radius: 50%;
  margin-top: 6px;
  background: var(--amber);
  box-shadow: 0 0 8px var(--amber-dim);
}
.news-date {
  font-size: 12px; color: var(--text-dim);
  font-family: 'JetBrains Mono', monospace;
  display: block; margin-bottom: 4px;
}
.news-content h4 {
  font-size: 15px; margin-bottom: 4px;
}
.news-content p {
  font-size: 13px; color: var(--text-dim);
}

/* ✦ About */
.about-section {
  padding: 100px 24px;
  background: var(--bg-secondary);
}
.about-content {
  display: grid; gap: 16px;
  max-width: 720px; margin: 0 auto;
}
.about-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}
.about-card h4 {
  font-size: 15px; margin-bottom: 8px;
  font-family: 'Inter', sans-serif;
}
.about-card p {
  font-size: 14px; color: var(--text-secondary); line-height: 1.8;
}
.about-links {
  list-style: none; margin-top: 12px;
}
.about-links li {
  margin-bottom: 6px;
}
.about-links a {
  color: var(--cyan); font-size: 14px;
}

/* ✦ Footer */
.footer {
  padding: 40px 24px;
  border-top: 1px solid var(--border);
}
.footer-inner {
  max-width: 1000px; margin: 0 auto;
  display: flex; flex-wrap: wrap; justify-content: space-between;
  align-items: center; gap: 16px;
}
.footer-brand {
  display: flex; align-items: center; gap: 8px;
  font-size: 14px; font-weight: 600;
  font-family: 'Noto Serif SC', serif;
}
.footer-icon { color: var(--cyan); }
.footer-links { display: flex; gap: 16px; }
.footer-links a { font-size: 13px; color: var(--text-dim); }
.footer-links a:hover { color: var(--cyan); }
.footer-copy {
  width: 100%; text-align: center;
  font-size: 12px; color: var(--text-dim);
  margin-top: 8px;
}

/* ✦ Back to Top */
.back-to-top {
  position: fixed; bottom: 32px; right: 32px;
  width: 44px; height: 44px; border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-secondary);
  font-size: 20px; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  opacity: 0; visibility: hidden;
  transform: translateY(16px);
  transition: all var(--transition);
  z-index: 100;
}
.back-to-top.visible {
  opacity: 1; visibility: visible;
  transform: translateY(0);
}
.back-to-top:hover {
  background: var(--bg-card-hover);
  border-color: var(--cyan);
  color: var(--cyan);
}

/* ✦ Scroll Reveal */
[data-reveal] {
  opacity: 0; transform: translateY(40px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}
[data-reveal].revealed {
  opacity: 1; transform: translateY(0);
}

/* ✦ Responsive */
@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute; top: var(--nav-height); left: 0; right: 0;
    flex-direction: column; gap: 0;
    background: rgba(10, 10, 15, 0.98);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
    padding: 8px;
  }
  .nav-links.open { display: flex; }
  .nav-links a {
    padding: 12px 16px; width: 100%;
    border-radius: var(--radius-sm);
  }
  .nav-toggle { display: block; }

  .hero-stats { flex-direction: column; gap: 16px; }
  .stat-divider { width: 40px; height: 1px; }

  .topic-grid { grid-template-columns: repeat(2, 1fr); }
  .about-content { padding: 0 8px; }
  .back-to-top { bottom: 20px; right: 20px; }
}

@media (max-width: 480px) {
  .topic-grid { grid-template-columns: 1fr; }
  .module-section, .about-section { padding: 64px 16px; }
  .article-item { flex-direction: column; gap: 8px; padding: 16px; }
  .footer-inner { flex-direction: column; text-align: center; }
}

/* ✦ Particle Canvas */
#heroBg {
  pointer-events: none;
}