:root {
  --primary: #2563eb;
  --primary-dark: #1e40af;
  --accent: #06b6d4;
  --ink: #0f172a;
  --muted: #64748b;
  --bg: #f8fafc;
  --card: #ffffff;
  --radius: 16px;
  --shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* ===== 导航 ===== */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  transition: background .3s, box-shadow .3s;
}
.navbar.scrolled {
  background: rgba(255, 255, 255, .85);
  backdrop-filter: blur(12px);
  box-shadow: 0 2px 16px rgba(15, 23, 42, .08);
}
.navbar.scrolled .nav-links a, .navbar.scrolled .brand { color: var(--ink); }
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.brand { display: flex; align-items: center; gap: 10px; font-size: 20px; font-weight: 700; color: #fff; }
.brand-mark {
  width: 30px; height: 30px; border-radius: 9px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  box-shadow: 0 4px 12px rgba(37, 99, 235, .4);
}
.nav-links { display: flex; gap: 6px; }
.nav-links a {
  padding: 8px 16px; border-radius: 999px; font-size: 15px; color: rgba(255,255,255,.9);
  transition: background .2s, color .2s;
}
.nav-links a:hover, .nav-links a.active { background: rgba(37,99,235,.12); color: var(--primary); }
.navbar:not(.scrolled) .nav-links a:hover, .navbar:not(.scrolled) .nav-links a.active { color: #fff; background: rgba(255,255,255,.15); }
.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: 0; cursor: pointer; padding: 8px; }
.nav-toggle span { width: 24px; height: 2px; background: #fff; border-radius: 2px; transition: .3s; }
.navbar.scrolled .nav-toggle span { background: var(--ink); }

/* ===== Hero ===== */
.hero {
  position: relative; min-height: 88vh; display: flex; align-items: center;
  background: linear-gradient(135deg, #0f172a 0%, #1e3a8a 55%, #0e7490 100%);
  color: #fff; overflow: hidden;
}
.hero::before {
  content: ""; position: absolute; inset: -50%;
  background:
    radial-gradient(circle at 20% 30%, rgba(37,99,235,.45), transparent 40%),
    radial-gradient(circle at 80% 70%, rgba(6,182,212,.35), transparent 40%);
  animation: heroFloat 14s ease-in-out infinite alternate;
}
@keyframes heroFloat { from { transform: translate(-2%, -1%) scale(1); } to { transform: translate(2%, 2%) scale(1.06); } }
.hero-inner { position: relative; z-index: 1; padding: 120px 0 80px; }
.hero-tag {
  display: inline-block; padding: 6px 16px; border-radius: 999px;
  background: rgba(255,255,255,.12); border: 1px solid rgba(255,255,255,.2);
  font-size: 14px; letter-spacing: 1px; margin-bottom: 22px;
}
.hero h1 { font-size: clamp(32px, 5.5vw, 58px); line-height: 1.25; font-weight: 800; margin-bottom: 20px; }
.hero p { font-size: 18px; color: rgba(255,255,255,.75); max-width: 620px; margin-bottom: 36px; }
.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; }
.btn {
  display: inline-block; padding: 13px 32px; border-radius: 999px; font-size: 16px;
  transition: transform .2s, box-shadow .2s; cursor: pointer; border: 0;
}
.btn:hover { transform: translateY(-2px); }
.btn-primary { background: linear-gradient(135deg, var(--primary), var(--accent)); color: #fff; box-shadow: 0 8px 24px rgba(37,99,235,.4); }
.btn-ghost { border: 1px solid rgba(255,255,255,.4); color: #fff; }
.btn-ghost:hover { background: rgba(255,255,255,.1); }

/* ===== 区块通用 ===== */
.section { padding: 88px 0; }
.section-head { text-align: center; margin-bottom: 52px; }
.section-head .eyebrow { color: var(--primary); font-weight: 600; letter-spacing: 2px; font-size: 14px; text-transform: uppercase; }
.section-head h2 { font-size: clamp(26px, 3.5vw, 38px); margin-top: 8px; }
.section-head p { color: var(--muted); margin-top: 10px; }
.section.alt { background: #fff; }

/* 数字统计 */
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.stat {
  background: var(--card); border-radius: var(--radius); padding: 30px 20px; text-align: center;
  box-shadow: var(--shadow); transition: transform .25s;
}
.stat:hover { transform: translateY(-6px); }
.stat .num { font-size: 38px; font-weight: 800; background: linear-gradient(135deg, var(--primary), var(--accent)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.stat .label { color: var(--muted); margin-top: 4px; }

/* 卡片网格 */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.card {
  background: var(--card); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow);
  transition: transform .25s, box-shadow .25s; display: flex; flex-direction: column;
}
.card:hover { transform: translateY(-8px); box-shadow: 0 18px 40px rgba(15,23,42,.14); }
.card .thumb { height: 200px; background: linear-gradient(135deg, #dbeafe, #cffafe); display: flex; align-items: center; justify-content: center; color: var(--primary); font-size: 42px; font-weight: 800; overflow: hidden; }
.card .thumb img { width: 100%; height: 100%; object-fit: cover; transition: transform .4s; }
.card:hover .thumb img { transform: scale(1.06); }
.card .body { padding: 22px; flex: 1; display: flex; flex-direction: column; }
.card h3 { font-size: 18px; margin-bottom: 8px; }
.card p { color: var(--muted); font-size: 14px; flex: 1;
  display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.card .more { margin-top: 14px; color: var(--primary); font-size: 14px; font-weight: 600; }

/* 列表页 */
.page-head { padding: 140px 0 60px; background: linear-gradient(135deg, #0f172a, #1e3a8a); color: #fff; }
.page-head h1 { font-size: clamp(28px, 4vw, 42px); }
.list { display: flex; flex-direction: column; gap: 16px; }
.list-item {
  background: #fff; border-radius: var(--radius); padding: 26px 28px; box-shadow: var(--shadow);
  display: flex; justify-content: space-between; align-items: center; gap: 20px; transition: transform .2s;
}
.list-item:hover { transform: translateX(6px); }
.list-item h3 { font-size: 18px; margin-bottom: 6px; }
.list-item p { color: var(--muted); font-size: 14px; }
.list-item .arrow { color: var(--primary); font-size: 22px; flex-shrink: 0; }

/* 详情页 */
.detail { max-width: 860px; margin: 0 auto; padding: 150px 24px 90px; }
.detail h1 { font-size: clamp(26px, 4vw, 40px); margin-bottom: 14px; }
.detail .meta { color: var(--muted); font-size: 14px; margin-bottom: 36px; padding-bottom: 20px; border-bottom: 1px solid #e2e8f0; }
.detail .content { font-size: 17px; }
.detail .content img { border-radius: var(--radius); margin: 18px 0; }
.detail .content p { margin-bottom: 16px; }

/* 关于区块 */
.about-grid { display: grid; grid-template-columns: 1.1fr .9fr; gap: 48px; align-items: center; }
.about-visual {
  border-radius: var(--radius); min-height: 340px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  box-shadow: var(--shadow); position: relative; overflow: hidden;
}
.about-visual::after {
  content: ""; position: absolute; right: -60px; bottom: -60px; width: 220px; height: 220px;
  border-radius: 50%; background: rgba(255,255,255,.15);
}
.about-text h2 { font-size: clamp(24px, 3vw, 34px); margin-bottom: 16px; }
.about-text p { color: var(--muted); margin-bottom: 14px; }

/* 底部 */
.footer { background: #0f172a; color: #94a3b8; margin-top: 40px; }
.footer-inner { display: flex; justify-content: space-between; gap: 40px; padding: 56px 24px 30px; flex-wrap: wrap; }
.footer-brand { color: #fff; font-size: 20px; font-weight: 700; margin-bottom: 10px; }
.footer-desc { max-width: 420px; font-size: 14px; }
.footer-nav { display: flex; gap: 20px; flex-wrap: wrap; align-items: flex-start; }
.footer-nav a { font-size: 14px; transition: color .2s; }
.footer-nav a:hover { color: #fff; }
.footer-copy { text-align: center; padding: 18px; border-top: 1px solid rgba(255,255,255,.08); font-size: 13px; }

/* 动效 */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity .7s ease, transform .7s ease; }
.reveal.visible { opacity: 1; transform: none; }

/*  loading / 返回顶部 */
.page-loading { min-height: 70vh; display: flex; align-items: center; justify-content: center; }
.spinner { width: 44px; height: 44px; border: 4px solid #e2e8f0; border-top-color: var(--primary); border-radius: 50%; animation: spin .8s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }
.back-top {
  position: fixed; right: 26px; bottom: 26px; width: 46px; height: 46px; border-radius: 50%;
  border: 0; background: var(--primary); color: #fff; font-size: 20px; cursor: pointer;
  box-shadow: 0 8px 20px rgba(37,99,235,.4); opacity: 0; pointer-events: none; transition: opacity .3s; z-index: 90;
}
.back-top.show { opacity: 1; pointer-events: auto; }
.empty { text-align: center; color: var(--muted); padding: 60px 0; }

/* 响应式 */
@media (max-width: 900px) {
  .cards { grid-template-columns: repeat(2, 1fr); }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .about-grid { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .nav-links {
    position: fixed; top: 68px; left: 0; right: 0; flex-direction: column;
    background: #fff; padding: 12px; box-shadow: var(--shadow);
    transform: translateY(-150%); transition: transform .3s; z-index: 99;
  }
  .nav-links.open { transform: none; }
  .nav-links a { color: var(--ink) !important; }
  .nav-toggle { display: flex; }
  .cards { grid-template-columns: 1fr; }
  .section { padding: 60px 0; }
}