/* ============================================
   AI 未来创想家 - 深空黑玻璃态主题
   ============================================ */

:root {
  /* 深空背景（不是纯黑，加蓝紫调避免压抑） */
  --bg-base: #06081a;
  --bg-deep: #04050f;
  --bg-card: rgba(255, 255, 255, 0.035);
  --bg-card-hover: rgba(255, 255, 255, 0.06);
  --bg-glass: rgba(15, 18, 38, 0.5);

  /* 玻璃态边框 */
  --border-soft: rgba(255, 255, 255, 0.06);
  --border-medium: rgba(255, 255, 255, 0.12);
  --border-strong: rgba(255, 255, 255, 0.2);

  /* 文字色 */
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-mute: #94a3b8;
  --text-faint: #64748b;

  /* 强调色（用于卡片顶部光带） */
  --c-a1: #34d399;       /* 绿 - 启蒙 */
  --c-a2: #60a5fa;       /* 蓝 - 探索 */
  --c-a3: #a78bfa;       /* 紫 - 进阶 */
  --c-a4: #fb923c;       /* 橙 - 专业 */
  --c-purple: #a78bfa;
  --c-pink: #ec4899;
  --c-blue: #60a5fa;
  --c-green: #34d399;
  --c-amber: #fbbf24;
  --c-cyan: #22d3ee;

  /* 渐变 */
  --g-primary: linear-gradient(135deg, #a78bfa 0%, #ec4899 50%, #fb923c 100%);
  --g-cool: linear-gradient(135deg, #60a5fa 0%, #a78bfa 50%, #ec4899 100%);
  --g-warm: linear-gradient(135deg, #fb923c 0%, #ec4899 50%, #a78bfa 100%);
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial,
    sans-serif;
  color: var(--text-primary);
  line-height: 1.7;
  background: var(--bg-base);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
}

/* 全局背景：3 个大型彩色光晕（氛围光） */
body::before {
  content: "";
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  z-index: -1;
  background:
    radial-gradient(ellipse 80% 60% at 15% 10%, rgba(139, 92, 246, 0.18) 0%, transparent 60%),
    radial-gradient(ellipse 70% 50% at 85% 30%, rgba(236, 72, 153, 0.13) 0%, transparent 60%),
    radial-gradient(ellipse 60% 50% at 50% 100%, rgba(96, 165, 250, 0.1) 0%, transparent 60%);
  pointer-events: none;
}

/* 顶部还有一条横线光（增加层次） */
body::after {
  content: "";
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent 0%, rgba(167, 139, 250, 0.5) 50%, transparent 100%);
  z-index: 1;
  pointer-events: none;
}

::selection { background: rgba(167, 139, 250, 0.4); color: #fff; }

/* ===== 通用容器 ===== */
.container-x {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

/* ===== 导航栏（玻璃态） ===== */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(6, 8, 26, 0.6);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border-soft);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 18px;
  transition: opacity 0.2s;
}
.brand:hover { opacity: 0.85; }
.brand-mark {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--g-primary);
  display: grid;
  place-items: center;
  color: #fff;
  font-weight: 800;
  box-shadow: 0 6px 20px -8px rgba(167, 139, 250, 0.6);
}
.brand-sub {
  font-size: 11px;
  font-weight: 500;
  color: var(--text-mute);
  letter-spacing: 2px;
  text-transform: uppercase;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 2px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links a {
  display: inline-block;
  padding: 8px 14px;
  border-radius: 8px;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  transition: all 0.2s;
  position: relative;
}
.nav-links a:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.05);
}
.nav-links a.active {
  color: var(--text-primary);
  background: rgba(167, 139, 250, 0.15);
  font-weight: 600;
}
.nav-links a.active::after {
  content: "";
  position: absolute;
  bottom: -2px; left: 14px; right: 14px;
  height: 2px;
  background: var(--g-primary);
  border-radius: 2px;
}
.nav-cta {
  background: var(--g-primary) !important;
  color: #fff !important;
  padding: 9px 18px !important;
  border-radius: 10px !important;
  font-weight: 600 !important;
  box-shadow: 0 6px 18px -6px rgba(167, 139, 250, 0.5);
  margin-left: 6px;
}
.nav-cta:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 22px -6px rgba(167, 139, 250, 0.7);
}
.nav-cta::after { display: none !important; }
.nav-toggle {
  display: none;
  background: transparent;
  border: 0;
  font-size: 24px;
  cursor: pointer;
  color: var(--text-primary);
}
@media (max-width: 900px) {
  .nav-links { display: none; }
  .nav-toggle { display: inline-block; }
  .nav-links.open {
    display: flex;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: rgba(6, 8, 26, 0.95);
    backdrop-filter: blur(20px);
    padding: 8px 16px 16px;
    border-bottom: 1px solid var(--border-soft);
  }
  .nav-links.open a { padding: 12px 14px; }
  .nav-links.open a.active::after { display: none; }
}

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 12px;
  text-decoration: none;
  font-weight: 600;
  font-size: 15px;
  border: 0;
  cursor: pointer;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  font-family: inherit;
}
.btn-primary {
  background: var(--g-primary);
  color: #fff;
  box-shadow: 0 8px 22px -8px rgba(167, 139, 250, 0.6);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 30px -8px rgba(167, 139, 250, 0.7);
}
.btn-ghost {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
  border: 1px solid var(--border-medium);
  backdrop-filter: blur(10px);
}
.btn-ghost:hover {
  border-color: var(--border-strong);
  background: rgba(255, 255, 255, 0.08);
  transform: translateY(-1px);
}
.btn-outline {
  background: transparent;
  color: var(--c-purple);
  border: 1.5px solid var(--c-purple);
}
.btn-outline:hover { background: var(--c-purple); color: #fff; }
.btn-lg { padding: 14px 28px; font-size: 16px; }

/* ===== 通用块 ===== */
.section { padding: 80px 0; position: relative; }
.section-sm { padding: 56px 0; }
@media (max-width: 768px) { .section { padding: 56px 0; } }

.eyebrow {
  display: inline-block;
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  color: var(--c-purple);
  background: rgba(167, 139, 250, 0.12);
  border: 1px solid rgba(167, 139, 250, 0.2);
  margin-bottom: 16px;
  letter-spacing: 0.5px;
}
.section-title {
  font-size: clamp(28px, 4vw, 44px);
  font-weight: 800;
  line-height: 1.25;
  margin: 0 0 14px;
  letter-spacing: -0.5px;
  color: var(--text-primary);
}
.section-sub {
  font-size: 17px;
  color: var(--text-secondary);
  max-width: 720px;
  margin: 0 auto 40px;
  text-align: center;
}
.text-center { text-align: center; }
.text-soft { color: var(--text-secondary); }
.text-mute { color: var(--text-mute); }
.text-sm { font-size: 14px; }
.text-xs { font-size: 12px; }
.font-bold { font-weight: 700; }
.relative { position: relative; }

/* ===== 玻璃态卡片（核心） ===== */
.card {
  background: var(--bg-card);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border: 1px solid var(--border-soft);
  border-radius: 20px;
  padding: 28px;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}
/* 顶部彩色光带（每张卡片可有不同颜色） */
.card[class*="glow"],
.stat-card[class*="glow"],
.unit-card[class*="glow"],
.brain-card[class*="glow"],
.expert-card[class*="glow"],
.cssrm-card[class*="glow"],
.video-card[class*="glow"],
.bd-video[class*="glow"] {
  position: relative;
  overflow: visible !important;
}
.card[class*="glow"] > *,
.stat-card[class*="glow"] > *,
.unit-card[class*="glow"] > *,
.brain-card[class*="glow"] > *,
.expert-card[class*="glow"] > *,
.cssrm-card[class*="glow"] > *,
.video-card[class*="glow"] > *,
.bd-video[class*="glow"] > * { position: relative; z-index: 1; }
.card[class*="glow"]::before,
.stat-card[class*="glow"]::before,
.unit-card[class*="glow"]::before,
.brain-card[class*="glow"]::before,
.expert-card[class*="glow"]::before,
.cssrm-card[class*="glow"]::before,
.video-card[class*="glow"]::before,
.bd-video[class*="glow"]::before {
  content: "";
  position: absolute;
  top: -2px; left: 12%; right: 12%;
  height: 3px;
  background: var(--glow, #a78bfa);
  border-radius: 3px;
  z-index: 5;
  box-shadow: 0 0 12px 2px var(--glow, #a78bfa), 0 0 24px 4px var(--glow, rgba(167, 139, 250, 0.5));
  opacity: 1;
  pointer-events: none;
}
/* 角落光晕 */
.card.glow-corner::after {
  content: "";
  position: absolute;
  top: -50%; right: -50%;
  width: 200px; height: 200px;
  background: radial-gradient(circle, var(--glow, rgba(167, 139, 250, 0.3)) 0%, transparent 70%);
  filter: blur(30px);
  opacity: 0.5;
  pointer-events: none;
  transition: opacity 0.3s;
}
.card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-medium);
  transform: translateY(-4px);
  box-shadow:
    0 20px 40px -20px rgba(0, 0, 0, 0.5),
    0 0 0 1px rgba(255, 255, 255, 0.08),
    0 0 60px -20px var(--glow, rgba(167, 139, 250, 0.4));
}
.card:hover.glow-corner::after { opacity: 0.9; }

/* 卡片颜色变体（所有使用 .glow-* 类的元素） */
.card.glow-green, .stat-card.glow-green, .unit-card.glow-green, .brain-card.glow-green,
.expert-card.glow-green, .cssrm-card.glow-green, .video-card.glow-green, .bd-video.glow-green { --glow: #34d399; --c-glow: #34d399; }
.card.glow-blue, .stat-card.glow-blue, .unit-card.glow-blue, .brain-card.glow-blue,
.expert-card.glow-blue, .cssrm-card.glow-blue, .video-card.glow-blue, .bd-video.glow-blue { --glow: #60a5fa; --c-glow: #60a5fa; }
.card.glow-purple, .stat-card.glow-purple, .unit-card.glow-purple, .brain-card.glow-purple,
.expert-card.glow-purple, .cssrm-card.glow-purple, .video-card.glow-purple, .bd-video.glow-purple { --glow: #a78bfa; --c-glow: #a78bfa; }
.card.glow-orange, .stat-card.glow-orange, .unit-card.glow-orange, .brain-card.glow-orange,
.expert-card.glow-orange, .cssrm-card.glow-orange, .video-card.glow-orange, .bd-video.glow-orange { --glow: #fb923c; --c-glow: #fb923c; }
.card.glow-pink, .stat-card.glow-pink, .unit-card.glow-pink, .brain-card.glow-pink,
.expert-card.glow-pink, .cssrm-card.glow-pink, .video-card.glow-pink, .bd-video.glow-pink { --glow: #ec4899; --c-glow: #ec4899; }
.card.glow-cyan, .stat-card.glow-cyan, .unit-card.glow-cyan, .brain-card.glow-cyan,
.expert-card.glow-cyan, .cssrm-card.glow-cyan, .video-card.glow-cyan, .bd-video.glow-cyan { --glow: #22d3ee; --c-glow: #22d3ee; }
.card.glow-amber, .stat-card.glow-amber, .unit-card.glow-amber, .brain-card.glow-amber,
.expert-card.glow-amber, .cssrm-card.glow-amber, .video-card.glow-amber, .bd-video.glow-amber { --glow: #fbbf24; --c-glow: #fbbf24; }

/* ===== Hero（深色 + 大光晕） ===== */
.hero {
  position: relative;
  padding: 120px 0 80px;
  background: linear-gradient(180deg, transparent 0%, rgba(6, 8, 26, 0.5) 100%);
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  top: -200px; right: -200px;
  width: 700px; height: 700px;
  background: radial-gradient(circle, rgba(167, 139, 250, 0.3) 0%, transparent 70%);
  filter: blur(60px);
  z-index: 0;
  pointer-events: none;
}
.hero::after {
  content: "";
  position: absolute;
  bottom: -300px; left: -200px;
  width: 700px; height: 700px;
  background: radial-gradient(circle, rgba(236, 72, 153, 0.2) 0%, transparent 70%);
  filter: blur(60px);
  z-index: 0;
  pointer-events: none;
}
.hero-inner { position: relative; z-index: 1; }

/* 渐变文字 */
.gradient-text {
  background: var(--g-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.gradient-text-cool {
  background: var(--g-cool);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ===== 标签徽章 ===== */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
  background: rgba(167, 139, 250, 0.12);
  color: var(--c-purple);
  border: 1px solid rgba(167, 139, 250, 0.15);
}
.badge.badge-green { background: rgba(52, 211, 153, 0.12); color: var(--c-green); border-color: rgba(52, 211, 153, 0.2); }
.badge.badge-blue { background: rgba(96, 165, 250, 0.12); color: var(--c-blue); border-color: rgba(96, 165, 250, 0.2); }
.badge.badge-pink { background: rgba(236, 72, 153, 0.12); color: var(--c-pink); border-color: rgba(236, 72, 153, 0.2); }
.badge.badge-amber { background: rgba(251, 191, 36, 0.12); color: var(--c-amber); border-color: rgba(251, 191, 36, 0.2); }

/* ===== 页脚 ===== */
.footer {
  background: linear-gradient(180deg, transparent 0%, rgba(4, 5, 15, 0.8) 100%);
  border-top: 1px solid var(--border-soft);
  padding: 60px 0 30px;
  margin-top: 80px;
  position: relative;
}
.footer a { color: var(--text-secondary); text-decoration: none; transition: color 0.2s; }
.footer a:hover { color: var(--c-purple); }
.footer-title {
  color: var(--text-primary);
  font-weight: 700;
  margin-bottom: 18px;
  font-size: 15px;
}
.footer-list { list-style: none; padding: 0; margin: 0; }
.footer-list li { margin-bottom: 10px; }
.footer-bottom {
  border-top: 1px solid var(--border-soft);
  margin-top: 40px;
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 13px;
  color: var(--text-mute);
}

/* ===== 单元卡片（课程详情） ===== */
.unit-card {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border-soft);
  border-radius: 18px;
  padding: 24px;
  display: flex;
  gap: 18px;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}
.unit-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent 0%, var(--glow, #a78bfa) 50%, transparent 100%);
}
.unit-card:hover {
  border-color: var(--border-medium);
  transform: translateY(-3px);
  box-shadow: 0 16px 32px -16px rgba(167, 139, 250, 0.3);
}
.unit-num {
  flex-shrink: 0;
  width: 56px;
  height: 56px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  font-size: 22px;
  font-weight: 800;
  color: #fff;
  background: var(--g-primary);
  box-shadow: 0 6px 16px -6px rgba(167, 139, 250, 0.5);
}
.unit-card-body { flex: 1; }
.unit-title { font-size: 18px; font-weight: 700; margin: 0 0 8px; color: var(--text-primary); }
.unit-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 12px 0;
}
.unit-meta .badge { background: rgba(255,255,255,0.05); color: var(--text-secondary); border-color: var(--border-soft); }
.unit-tag {
  display: inline-block;
  font-size: 12px;
  padding: 2px 8px;
  border-radius: 6px;
  background: rgba(251, 191, 36, 0.12);
  color: var(--c-amber);
  font-weight: 600;
  margin-right: 4px;
}

/* ===== 课时数据卡 ===== */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin: 32px 0;
}
.stat-card {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border-soft);
  border-radius: 16px;
  padding: 22px;
  text-align: center;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  min-height: 120px;
  position: relative;
  overflow: visible;
  transition: all 0.3s;
}
.stat-card:hover { transform: translateY(-3px); border-color: var(--border-medium); }
.stat-num {
  font-size: 28px;
  font-weight: 800;
  background: var(--g-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
  word-break: break-word;
}
.stat-num.green { background: var(--c-green); -webkit-background-clip: text; background-clip: text; }
.stat-num.blue { background: var(--c-blue); -webkit-background-clip: text; background-clip: text; }
.stat-num.purple { background: var(--c-purple); -webkit-background-clip: text; background-clip: text; }
.stat-num.orange { background: var(--c-orange, #fb923c); -webkit-background-clip: text; background-clip: text; }
.stat-num.amber { background: var(--c-amber); -webkit-background-clip: text; background-clip: text; }
.stat-num.cyan { background: var(--c-cyan); -webkit-background-clip: text; background-clip: text; }
.stat-num.pink { background: var(--c-pink); -webkit-background-clip: text; background-clip: text; }
.stat-num { color: var(--glow, #a78bfa); }
.stat-label { font-size: 13px; color: var(--text-mute); margin-top: 4px; }
@media (max-width: 768px) { .stat-grid { grid-template-columns: repeat(2, 1fr); } }

/* ===== 脑科模块卡 ===== */
.brain-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}
.brain-card {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border-soft);
  border-radius: 18px;
  padding: 24px 18px;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s;
  text-decoration: none;
  color: inherit;
  display: block;
  position: relative;
  overflow: hidden;
}
.brain-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent 0%, var(--glow, #a78bfa) 50%, transparent 100%);
}
.brain-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-medium);
  box-shadow: 0 16px 32px -16px rgba(167, 139, 250, 0.3);
}
.brain-icon { font-size: 36px; margin-bottom: 8px; }
.brain-code {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  color: var(--c-purple);
  background: rgba(167, 139, 250, 0.12);
  padding: 2px 8px;
  border-radius: 6px;
  margin-bottom: 6px;
}
.brain-title { font-size: 16px; font-weight: 700; margin: 4px 0; color: var(--text-primary); }
.brain-desc { font-size: 13px; color: var(--text-mute); }
@media (max-width: 900px) { .brain-grid { grid-template-columns: repeat(2, 1fr); } }

/* ===== 视频卡（深色） ===== */
.video-card {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border-soft);
  border-radius: 18px;
  overflow: hidden;
  transition: all 0.3s;
  text-decoration: none;
  color: inherit;
  display: block;
  position: relative;
}
.video-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-medium);
  box-shadow: 0 20px 40px -20px rgba(167, 139, 250, 0.3);
}
.video-thumb {
  aspect-ratio: 16/9;
  background: linear-gradient(135deg, #1a1d3a 0%, #0a0e27 100%);
  position: relative;
  display: grid;
  place-items: center;
  color: rgba(255, 255, 255, 0.6);
  font-size: 48px;
}
.video-thumb::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(167, 139, 250, 0.4) 0%, rgba(96, 165, 250, 0.3) 100%);
}
.video-thumb > * { position: relative; z-index: 1; }
.video-thumb::after {
  content: "▶";
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  width: 60px; height: 60px;
  background: rgba(255, 255, 255, 0.95);
  color: #0a0e27;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-size: 20px;
  padding-left: 4px;
  z-index: 2;
  opacity: 0;
  transition: opacity 0.3s;
  box-shadow: 0 8px 24px -8px rgba(0, 0, 0, 0.4);
}
.video-card:hover .video-thumb::after { opacity: 1; }
.video-duration {
  position: absolute;
  bottom: 8px; right: 8px;
  background: rgba(0, 0, 0, 0.7);
  color: #fff;
  padding: 2px 8px;
  border-radius: 6px;
  font-size: 12px;
  font-weight: 600;
  z-index: 2;
}
.video-body { padding: 16px; }
.video-title { font-size: 15px; font-weight: 700; margin: 0 0 6px; color: var(--text-primary); }
.video-meta { font-size: 12px; color: var(--text-mute); }

/* ===== 课程阶段大卡（4 大年龄段） ===== */
.stage-card {
  position: relative;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border-soft);
  border-radius: 24px;
  padding: 36px 32px;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  overflow: hidden;
}
.stage-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent 0%, var(--glow, #a78bfa) 30%, var(--glow, #a78bfa) 70%, transparent 100%);
  opacity: 0.9;
}
.stage-card::after {
  content: "";
  position: absolute;
  top: -100px; right: -100px;
  width: 300px; height: 300px;
  background: radial-gradient(circle, var(--glow, rgba(167, 139, 250, 0.2)) 0%, transparent 70%);
  filter: blur(40px);
  z-index: 0;
  pointer-events: none;
  opacity: 0.6;
  transition: opacity 0.3s;
}
.stage-card > * { position: relative; z-index: 1; }
.stage-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-medium);
  box-shadow: 0 30px 60px -25px rgba(167, 139, 250, 0.4);
}
.stage-card:hover::after { opacity: 1; }
.stage-emoji {
  font-size: 56px;
  line-height: 1;
  margin-bottom: 12px;
}
.stage-tag {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  color: var(--glow, var(--c-purple));
  background: rgba(167, 139, 250, 0.1);
  padding: 4px 10px;
  border-radius: 6px;
  margin-bottom: 6px;
}
.stage-title { font-size: 24px; font-weight: 800; margin: 8px 0 12px; color: var(--text-primary); }
.stage-desc { color: var(--text-secondary); margin: 0 0 20px; }
.stage-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin: 18px 0;
  padding: 16px 0;
  border-top: 1px dashed var(--border-soft);
  border-bottom: 1px dashed var(--border-soft);
}
.stage-stat-label { font-size: 12px; color: var(--text-mute); }
.stage-stat-val { font-size: 15px; font-weight: 700; color: var(--text-primary); }

/* ===== CSSRM 三柱 ===== */
.cssrm-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}
.cssrm-card {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border-soft);
  border-radius: 18px;
  padding: 28px;
  text-align: center;
  transition: all 0.3s;
  position: relative;
  overflow: hidden;
}
.cssrm-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent 0%, var(--glow, #a78bfa) 50%, transparent 100%);
}
.cssrm-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-medium);
}
.cssrm-icon { font-size: 44px; margin-bottom: 10px; }
.cssrm-title { font-size: 20px; font-weight: 700; margin: 4px 0; color: var(--text-primary); }
.cssrm-desc { color: var(--text-secondary); font-size: 14px; }
@media (max-width: 768px) { .cssrm-grid { grid-template-columns: 1fr; } }

/* ===== 时间线（发展历程） ===== */
.timeline { position: relative; padding-left: 32px; }
.timeline::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 6px;
  bottom: 6px;
  width: 2px;
  background: linear-gradient(180deg, var(--c-purple) 0%, var(--c-pink) 100%);
}
.timeline-item { position: relative; margin-bottom: 36px; }
.timeline-item::before {
  content: "";
  position: absolute;
  left: -28px;
  top: 4px;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--g-primary);
  border: 3px solid var(--bg-base);
  box-shadow: 0 0 0 2px rgba(167, 139, 250, 0.4);
}
.timeline-year { font-size: 22px; font-weight: 800; color: var(--c-purple); }
.timeline-title { font-size: 18px; font-weight: 700; margin: 4px 0 8px; color: var(--text-primary); }
.timeline-desc { color: var(--text-secondary); }

/* ===== 专家卡 ===== */
.expert-card {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border-soft);
  border-radius: 18px;
  padding: 24px;
  text-align: center;
  transition: all 0.3s;
}
.expert-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-medium);
}
.expert-avatar {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  margin: 0 auto 12px;
  display: grid;
  place-items: center;
  font-size: 32px;
  font-weight: 800;
  color: #fff;
  background: var(--g-primary);
  box-shadow: 0 8px 20px -8px rgba(167, 139, 250, 0.5);
}

/* ===== 表单 ===== */
.form-group { margin-bottom: 18px; }
.form-label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--text-primary);
}
.form-label .req { color: #f87171; }
.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: 12px 14px;
  border: 1.5px solid var(--border-soft);
  border-radius: 10px;
  font-size: 15px;
  font-family: inherit;
  background: var(--bg-card);
  color: var(--text-primary);
  transition: all 0.2s;
  backdrop-filter: blur(10px);
}
.form-input::placeholder, .form-textarea::placeholder { color: var(--text-faint); }
.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  outline: 0;
  border-color: var(--c-purple);
  box-shadow: 0 0 0 3px rgba(167, 139, 250, 0.15);
  background: rgba(255, 255, 255, 0.05);
}
.form-textarea { min-height: 110px; resize: vertical; }

/* ===== 切换 Tab ===== */
.tabs {
  display: flex;
  gap: 6px;
  border-bottom: 1px solid var(--border-soft);
  margin-bottom: 24px;
  overflow-x: auto;
  padding-bottom: 1px;
}
.tab {
  padding: 10px 18px;
  font-size: 15px;
  font-weight: 600;
  color: var(--text-secondary);
  cursor: pointer;
  border: 0;
  background: transparent;
  border-bottom: 2px solid transparent;
  white-space: nowrap;
  transition: all 0.2s;
  font-family: inherit;
}
.tab:hover { color: var(--text-primary); }
.tab.active {
  color: var(--text-primary);
  border-bottom-color: var(--c-purple);
}
.tab-content { display: none; }
.tab-content.active { display: block; }

/* ===== 返回链接 ===== */
.back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 14px;
  margin-bottom: 18px;
  transition: color 0.2s;
  padding: 6px 12px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-soft);
}
.back-link:hover { color: var(--c-purple); border-color: var(--border-medium); }

/* ===== 工具 ===== */
.flex { display: flex; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.gap-2 { gap: 8px; } .gap-3 { gap: 12px; } .gap-4 { gap: 16px; }
.mt-1 { margin-top: 8px; } .mt-2 { margin-top: 16px; } .mt-3 { margin-top: 24px; } .mt-4 { margin-top: 32px; }
.mb-1 { margin-bottom: 8px; } .mb-2 { margin-bottom: 16px; } .mb-3 { margin-bottom: 24px; } .mb-4 { margin-bottom: 32px; }

/* ===== 响应式 ===== */
@media (max-width: 768px) {
  .stage-card { padding: 24px 20px; }
  .stage-stats { grid-template-columns: 1fr 1fr; }
}