/* =========================================================
   刘先生探索大模型知识小屋 - 全局样式
   风格定位：AI 赛博科技风 / 深色霓虹 / 玻璃拟态
   ========================================================= */

:root {
  --bg-deep: #05060a;
  --bg-panel: rgba(16, 20, 32, 0.72);
  --bg-panel-solid: #0b0e18;
  --neon-cyan: #00f6ff;
  --neon-purple: #b14dff;
  --neon-pink: #ff3cf0;
  --neon-blue: #4d7bff;
  --text-main: #e8ecf7;
  --text-dim: #93a0c2;
  --text-faint: #5c6584;
  --border-glow: rgba(0, 246, 255, 0.25);
  --font-display: 'Orbitron', 'Space Grotesk', sans-serif;
  --font-body: 'Space Grotesk', 'Noto Sans SC', sans-serif;
  --font-cn: 'Noto Sans SC', 'Space Grotesk', sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg-deep);
  color: var(--text-main);
  font-family: var(--font-cn);
  line-height: 1.7;
  overflow-x: hidden;
  position: relative;
}

/* ---------- 背景层 ---------- */
#particle-canvas {
  position: fixed;
  inset: 0;
  z-index: 0;
  width: 100%;
  height: 100%;
  display: block;
}

.bg-grid {
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(0, 246, 255, 0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 246, 255, 0.045) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 20%, #000 40%, transparent 100%);
}

.bg-glow {
  position: fixed;
  z-index: 1;
  pointer-events: none;
  filter: blur(120px);
  opacity: 0.5;
}
.bg-glow.glow-1 { top: -200px; left: -150px; width: 500px; height: 500px; background: var(--neon-purple); }
.bg-glow.glow-2 { top: 30%; right: -200px; width: 500px; height: 500px; background: var(--neon-cyan); opacity: 0.3; }
.bg-glow.glow-3 { bottom: -200px; left: 30%; width: 600px; height: 400px; background: var(--neon-pink); opacity: 0.25; }

main, header, footer { position: relative; z-index: 2; }

/* ---------- 滚动条 ---------- */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: var(--bg-deep); }
::-webkit-scrollbar-thumb { background: linear-gradient(var(--neon-cyan), var(--neon-purple)); border-radius: 4px; }

/* ---------- 文本渐变 / 发光 ---------- */
.gradient-text {
  background: linear-gradient(90deg, var(--neon-cyan), var(--neon-purple) 50%, var(--neon-pink));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.glow-text { text-shadow: 0 0 12px currentColor; }

.font-display { font-family: var(--font-display); letter-spacing: 0.5px; }

/* ---------- 顶部导航 ---------- */
#site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(14px);
  background: rgba(5, 6, 10, 0.65);
  border-bottom: 1px solid rgba(0, 246, 255, 0.15);
}

.nav-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text-main);
}

.brand-icon {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, rgba(0,246,255,0.15), rgba(177,77,255,0.15));
  border: 1px solid var(--border-glow);
  box-shadow: 0 0 18px rgba(0, 246, 255, 0.25);
  font-size: 20px;
  color: var(--neon-cyan);
}

.brand-title { font-family: var(--font-display); font-size: 16px; font-weight: 700; letter-spacing: 1px; line-height: 1.2; }
.brand-sub { font-size: 11px; color: var(--text-faint); letter-spacing: 2px; text-transform: uppercase; }

.main-nav { display: flex; gap: 6px; align-items: center; }

.nav-link {
  color: var(--text-dim);
  text-decoration: none;
  font-size: 14px;
  padding: 9px 16px;
  border-radius: 999px;
  transition: all 0.25s ease;
  position: relative;
  font-weight: 500;
}
.nav-link:hover { color: var(--neon-cyan); background: rgba(0, 246, 255, 0.08); }
.nav-link.active { color: var(--bg-deep); background: linear-gradient(90deg, var(--neon-cyan), var(--neon-blue)); font-weight: 700; }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border-glow);
  color: var(--neon-cyan);
  border-radius: 8px;
  width: 40px;
  height: 40px;
  font-size: 18px;
  cursor: pointer;
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 26px;
  border-radius: 999px;
  font-weight: 700;
  text-decoration: none;
  font-size: 14px;
  cursor: pointer;
  border: none;
  transition: all 0.25s ease;
  font-family: var(--font-cn);
}
.btn-primary {
  background: linear-gradient(90deg, var(--neon-cyan), var(--neon-purple));
  color: #05060a;
  box-shadow: 0 0 25px rgba(0, 246, 255, 0.35);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 0 35px rgba(177, 77, 255, 0.5); }
.btn-outline {
  background: transparent;
  color: var(--neon-cyan);
  border: 1px solid var(--border-glow);
}
.btn-outline:hover { background: rgba(0, 246, 255, 0.08); border-color: var(--neon-cyan); }

/* ---------- 玻璃卡片 ---------- */
.glass-card {
  background: var(--bg-panel);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 20px;
  backdrop-filter: blur(16px);
  position: relative;
  overflow: hidden;
}
.glass-card::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  padding: 1px;
  background: linear-gradient(135deg, rgba(0,246,255,0.35), transparent 40%, rgba(177,77,255,0.3));
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  pointer-events: none;
}

/* ---------- Hero ---------- */
.hero-section {
  max-width: 1280px;
  margin: 0 auto;
  padding: 90px 24px 60px;
  text-align: center;
}

/* ---------- 首页 Logo 展示区 ---------- */
.hero-logo-wrap {
  display: flex;
  justify-content: center;
  margin-bottom: 36px;
}

.hero-logo-frame {
  position: relative;
  padding: 10px;
  border-radius: 26px;
  background: linear-gradient(135deg, rgba(0,246,255,0.35), rgba(177,77,255,0.25), rgba(255,60,240,0.3));
  box-shadow:
    0 0 40px rgba(0, 246, 255, 0.25),
    0 0 90px rgba(177, 77, 255, 0.18),
    0 25px 60px rgba(0, 0, 0, 0.45);
  animation: logo-float 5s ease-in-out infinite;
}

.hero-logo-frame::before {
  content: '';
  position: absolute;
  inset: -14px;
  border-radius: 32px;
  border: 1px solid rgba(0, 246, 255, 0.25);
  pointer-events: none;
}

.hero-logo-img {
  display: block;
  width: min(560px, 82vw);
  height: auto;
  border-radius: 18px;
  box-shadow: inset 0 0 0 1px rgba(255,255,255,0.06);
}

@keyframes logo-float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 18px;
  border-radius: 999px;
  border: 1px solid var(--border-glow);
  background: rgba(0, 246, 255, 0.06);
  color: var(--neon-cyan);
  font-size: 13px;
  letter-spacing: 1px;
  margin-bottom: 28px;
}
.hero-badge .dot { width: 7px; height: 7px; border-radius: 50%; background: var(--neon-cyan); box-shadow: 0 0 10px var(--neon-cyan); animation: pulse-dot 1.6s infinite; }
@keyframes pulse-dot { 0%,100% { opacity: 1; } 50% { opacity: 0.3; } }

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(34px, 6vw, 68px);
  font-weight: 900;
  line-height: 1.15;
  margin: 0 0 22px;
}

.hero-desc {
  max-width: 680px;
  margin: 0 auto 40px;
  color: var(--text-dim);
  font-size: 17px;
}

.hero-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; margin-bottom: 60px; }

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  max-width: 900px;
  margin: 0 auto;
}
.stat-box { padding: 20px 10px; text-align: center; }
.stat-num { font-family: var(--font-display); font-size: 30px; font-weight: 800; color: var(--neon-cyan); text-shadow: 0 0 14px rgba(0,246,255,0.4); }
.stat-label { font-size: 12px; color: var(--text-faint); margin-top: 6px; letter-spacing: 1px; }

/* ---------- Section 通用 ---------- */
.section {
  max-width: 1280px;
  margin: 0 auto;
  padding: 70px 24px;
}
.section-head { margin-bottom: 42px; text-align: center; }
.section-tag {
  font-size: 13px;
  color: var(--neon-purple);
  letter-spacing: 3px;
  text-transform: uppercase;
  font-family: var(--font-display);
}
.section-title { font-family: var(--font-display); font-size: clamp(26px, 4vw, 40px); font-weight: 800; margin: 10px 0 14px; }
.section-desc { color: var(--text-dim); max-width: 640px; margin: 0 auto; font-size: 15px; }

/* ---------- 文章卡片 ---------- */
.article-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 26px;
}

.article-card {
  padding: 0;
  display: flex;
  flex-direction: column;
  text-decoration: none;
  color: var(--text-main);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.article-card:hover { transform: translateY(-6px); box-shadow: 0 12px 40px rgba(0, 246, 255, 0.15); }

.article-cover {
  width: 100%;
  height: 190px;
  object-fit: cover;
  border-radius: 20px 20px 0 0;
  filter: saturate(1.1) contrast(1.05);
  border-bottom: 1px solid rgba(255,255,255,0.06);
}

.article-body { padding: 22px 22px 26px; flex: 1; display: flex; flex-direction: column; }

.article-category {
  display: inline-block;
  align-self: flex-start;
  font-size: 11px;
  padding: 4px 12px;
  border-radius: 999px;
  color: var(--neon-cyan);
  border: 1px solid var(--border-glow);
  background: rgba(0, 246, 255, 0.06);
  margin-bottom: 12px;
  letter-spacing: 1px;
}

.article-title { font-size: 18px; font-weight: 700; margin: 0 0 10px; line-height: 1.45; }
.article-summary { font-size: 13.5px; color: var(--text-dim); flex: 1; margin-bottom: 16px;
  display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }

.article-meta { display: flex; align-items: center; justify-content: space-between; font-size: 12px; color: var(--text-faint); border-top: 1px solid rgba(255,255,255,0.06); padding-top: 14px; }
.article-meta span { display: inline-flex; align-items: center; gap: 5px; }

/* ---------- 分类过滤 ---------- */
.filter-bar { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; margin-bottom: 40px; }
.filter-btn {
  padding: 9px 20px;
  border-radius: 999px;
  border: 1px solid rgba(255,255,255,0.1);
  background: rgba(255,255,255,0.03);
  color: var(--text-dim);
  cursor: pointer;
  font-size: 13.5px;
  transition: all 0.25s ease;
  font-family: var(--font-cn);
}
.filter-btn:hover { border-color: var(--neon-cyan); color: var(--neon-cyan); }
.filter-btn.active { background: linear-gradient(90deg, var(--neon-cyan), var(--neon-blue)); color: #05060a; border-color: transparent; font-weight: 700; }

/* ---------- 特性 / 关于卡片 ---------- */
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.feature-card { padding: 32px 26px; text-align: left; }
.feature-icon {
  width: 52px; height: 52px; border-radius: 14px;
  display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, rgba(0,246,255,0.15), rgba(177,77,255,0.15));
  color: var(--neon-cyan); font-size: 22px; margin-bottom: 18px;
  border: 1px solid var(--border-glow);
}
.feature-title { font-size: 17px; font-weight: 700; margin-bottom: 10px; }
.feature-desc { font-size: 14px; color: var(--text-dim); }

/* ---------- Footer ---------- */
#site-footer {
  border-top: 1px solid rgba(255,255,255,0.06);
  padding: 50px 24px 30px;
  margin-top: 60px;
}
.footer-inner { max-width: 1280px; margin: 0 auto; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 30px; }
.footer-col h4 { font-family: var(--font-display); font-size: 14px; color: var(--text-main); margin-bottom: 16px; letter-spacing: 1px; }
.footer-col a { display: block; color: var(--text-dim); text-decoration: none; font-size: 13.5px; margin-bottom: 10px; }
.footer-col a:hover { color: var(--neon-cyan); }
.footer-bottom { text-align: center; margin-top: 40px; padding-top: 24px; border-top: 1px solid rgba(255,255,255,0.06); color: var(--text-faint); font-size: 12.5px; line-height: 2; }
.footer-bottom .icp-link { color: var(--text-faint); text-decoration: none; transition: color 0.2s ease; }
.footer-bottom .icp-link:hover { color: var(--neon-cyan); }

/* ---------- 文章详情页 ---------- */
.article-detail { max-width: 820px; margin: 0 auto; padding: 60px 24px 100px; }
.detail-cover { width: 100%; height: 340px; object-fit: cover; border-radius: 22px; margin-bottom: 34px; border: 1px solid rgba(255,255,255,0.08); }
.detail-title { font-family: var(--font-display); font-size: clamp(24px, 4vw, 38px); font-weight: 800; margin-bottom: 18px; line-height: 1.3; }
.detail-meta { display: flex; gap: 20px; flex-wrap: wrap; color: var(--text-faint); font-size: 13.5px; margin-bottom: 34px; padding-bottom: 28px; border-bottom: 1px solid rgba(255,255,255,0.08); }
.detail-content { font-size: 16.5px; color: #d3d9ec; }
.detail-content h3 { font-family: var(--font-display); color: var(--neon-cyan); font-size: 21px; margin: 34px 0 14px; }
.detail-content p { margin: 0 0 18px; }
.detail-tags { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 36px; }
.tag-pill { font-size: 12.5px; padding: 6px 14px; border-radius: 999px; border: 1px solid var(--border-glow); color: var(--neon-purple); background: rgba(177,77,255,0.08); }

/* ---------- 表单 ---------- */
.form-group { margin-bottom: 20px; }
.form-label { display: block; font-size: 13.5px; color: var(--text-dim); margin-bottom: 8px; }
.form-input, .form-textarea, .form-select {
  width: 100%;
  padding: 13px 16px;
  border-radius: 12px;
  border: 1px solid rgba(255,255,255,0.1);
  background: rgba(255,255,255,0.03);
  color: var(--text-main);
  font-size: 14px;
  font-family: var(--font-cn);
  outline: none;
  transition: border-color 0.25s ease;
}
.form-input:focus, .form-textarea:focus, .form-select:focus { border-color: var(--neon-cyan); box-shadow: 0 0 0 3px rgba(0,246,255,0.12); }
.form-textarea { resize: vertical; min-height: 120px; }

/* ---------- 加载与空状态 ---------- */
.loading-state, .empty-state { text-align: center; padding: 80px 24px; color: var(--text-faint); }
.spinner { width: 40px; height: 40px; border: 3px solid rgba(0,246,255,0.15); border-top-color: var(--neon-cyan); border-radius: 50%; margin: 0 auto 16px; animation: spin 0.9s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- 管理后台 ---------- */
.admin-shell { max-width: 1100px; margin: 0 auto; padding: 50px 24px 100px; }
.admin-table { width: 100%; border-collapse: collapse; }
.admin-table th, .admin-table td { text-align: left; padding: 14px 12px; border-bottom: 1px solid rgba(255,255,255,0.08); font-size: 14px; }
.admin-table th { color: var(--text-faint); font-weight: 600; font-size: 12.5px; text-transform: uppercase; letter-spacing: 1px; }
.icon-btn { background: none; border: 1px solid rgba(255,255,255,0.1); color: var(--text-dim); width: 34px; height: 34px; border-radius: 8px; cursor: pointer; margin-right: 6px; }
.icon-btn:hover { border-color: var(--neon-cyan); color: var(--neon-cyan); }
.icon-btn.danger:hover { border-color: #ff4d6d; color: #ff4d6d; }

.modal-overlay { position: fixed; inset: 0; background: rgba(5,6,10,0.75); backdrop-filter: blur(6px); z-index: 100; display: none; align-items: center; justify-content: center; padding: 20px; }
.modal-overlay.open { display: flex; }
.modal-box { width: 100%; max-width: 640px; max-height: 88vh; overflow-y: auto; padding: 32px; }

/* ---------- 响应式 ---------- */
@media (max-width: 980px) {
  .article-grid { grid-template-columns: repeat(2, 1fr); }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 760px) {
  .main-nav { position: fixed; top: 73px; left: 0; right: 0; background: rgba(5,6,10,0.97); flex-direction: column; padding: 16px; gap: 4px; border-bottom: 1px solid var(--border-glow); display: none; }
  .main-nav.open { display: flex; }
  .nav-toggle { display: block; }
  .nav-link { width: 100%; text-align: center; }
  .article-grid { grid-template-columns: 1fr; }
  .feature-grid { grid-template-columns: 1fr; }
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
  .footer-inner { flex-direction: column; }
  .hero-logo-img { width: min(400px, 80vw); }
}