:root {
  /* 颜色系统：深蓝主色 + 中性灰 + 单一蓝色强调 */
  --navy-900: #0a1733;
  --navy-800: #0f2147;
  --navy-700: #16305f;
  --brand: #2563eb;
  --brand-light: #3b82f6;
  --brand-soft: #eff4ff;

  --ink: #0f172a;
  --text: #334155;
  --muted: #64748b;
  --line: #e2e8f0;
  --bg: #ffffff;
  --bg-soft: #f7f9fc;

  --radius: 14px;
  --radius-sm: 10px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, .06), 0 1px 3px rgba(15, 23, 42, .08);
  --shadow-md: 0 4px 16px rgba(15, 23, 42, .08);
  --shadow-lg: 0 20px 50px rgba(10, 23, 51, .18);
  --maxw: 1200px;

  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

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

body {
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }

a { color: inherit; text-decoration: none; }

/* 全局去掉黑色焦点边框，仅键盘导航显示柔和焦点环 */
:focus { outline: none; }
:focus-visible {
  outline: none;
  box-shadow: 0 0 0 3px rgba(37, 99, 235, .35);
  border-radius: 6px;
}
button { font-family: inherit; border: none; background: none; cursor: pointer; }

.container {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

/* ===================== 顶部导航 ===================== */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, .82);
  backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--line);
}
.nav-inner {
  height: 66px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 19px;
  color: var(--ink);
  letter-spacing: -.2px;
}
.brand .logo {
  height: 34px;
  display: grid;
  color: #fff;
  font-size: 17px;
  font-weight: 900;
}
.brand .logo svg { width: 20px; height: 20px; }
.brand small { color: var(--muted); font-weight: 500; font-size: 12px; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  list-style: none;
}
.nav-links a {
  display: block;
  padding: 8px 14px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 500;
  color: var(--text);
  transition: background .15s, color .15s;
}
.nav-links a:hover { background: var(--bg-soft); color: var(--ink); }
.nav-links a.active { color: var(--brand); background: var(--brand-soft); }

.nav-actions { display: flex; align-items: center; gap: 12px; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 22px;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 600;
  transition: transform .12s, box-shadow .2s, background .2s, border-color .2s;
  white-space: nowrap;
}
.btn-primary {
  background: var(--brand);
  color: #fff;
  box-shadow: 0 4px 14px rgba(37, 99, 235, .28);
}
.btn-primary:hover { background: var(--brand-light); transform: translateY(-1px); box-shadow: 0 8px 22px rgba(37, 99, 235, .36); }
.btn-ghost {
  background: #fff;
  color: var(--ink);
  border: 1px solid var(--line);
}
.btn-ghost:hover { border-color: var(--brand); color: var(--brand); }
.btn-lg { padding: 14px 30px; font-size: 16px; }

.nav-toggle { display: none; width: 42px; height: 42px; border-radius: 10px; }
.nav-toggle span, .nav-toggle span::before, .nav-toggle span::after {
  content: ""; display: block; width: 20px; height: 2px; background: var(--ink);
  position: relative; transition: .2s; margin: 0 auto;
}
.nav-toggle span::before { position: absolute; top: -6px; }
.nav-toggle span::after { position: absolute; top: 6px; }

/* ===================== 通用区块 ===================== */
.section { padding: 92px 0; }
.section-soft { background: var(--bg-soft); }
.section-head { text-align: center; max-width: 720px; margin: 0 auto 56px; }
.eyebrow {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .8px;
  text-transform: uppercase;
  color: var(--brand);
  background: var(--brand-soft);
  padding: 6px 14px;
  border-radius: 999px;
  margin-bottom: 18px;
}
.section-head h2 {
  font-size: clamp(28px, 4vw, 40px);
  line-height: 1.2;
  color: var(--ink);
  font-weight: 800;
  letter-spacing: -.5px;
  text-wrap: balance;
}
.section-head p {
  margin-top: 16px;
  font-size: 17px;
  color: var(--muted);
  text-wrap: pretty;
}

/* ===================== 卡片网格 ===================== */
.grid { display: grid; gap: 24px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px;
  transition: transform .2s, box-shadow .2s, border-color .2s;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); border-color: #cdd9ec; }
.card .ico {
  width: 50px; height: 50px;
  border-radius: 12px;
  background: var(--brand-soft);
  color: var(--brand);
  display: grid; place-items: center;
  margin-bottom: 18px;
}
.card .ico svg { width: 26px; height: 26px; }
.card h3 { font-size: 18px; color: var(--ink); font-weight: 700; margin-bottom: 8px; }
.card p { font-size: 15px; color: var(--muted); }

/* ===================== 页脚 ===================== */
.footer {
  background: var(--navy-900);
  color: #c7d2e4;
  padding: 64px 0 32px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr repeat(3, 1fr);
  gap: 40px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255,255,255,.1);
}
.footer .brand { color: #fff; }
.footer .brand small { color: #8ea0bd; }
.footer-col h4 { color: #fff; font-size: 15px; margin-bottom: 16px; font-weight: 700; }
.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 10px; }
.footer-col a { color: #9fb0cc; font-size: 14px; transition: color .15s; }
.footer-col a:hover { color: #fff; }
.footer-desc { font-size: 14px; color: #9fb0cc; margin: 16px 0; max-width: 320px; }
.footer-bottom {
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 13px;
  color: #7d8caa;
}

/* ===================== 通用页面头部（非首页） ===================== */
.page-hero {
  background: linear-gradient(180deg, var(--navy-900), var(--navy-800));
  color: #fff;
  padding: 84px 0 72px;
  text-align: center;
}
.page-hero .eyebrow { background: rgba(255,255,255,.12); color: #bcd0ff; }
.page-hero h1 {
  font-size: clamp(32px, 5vw, 50px);
  font-weight: 800;
  letter-spacing: -.6px;
  line-height: 1.15;
  text-wrap: balance;
}
.page-hero p {
  margin: 18px auto 0;
  max-width: 640px;
  font-size: 18px;
  color: #b9c6dd;
  text-wrap: pretty;
}

/* ===================== 动画 ===================== */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }

/* ===================== 响应式 ===================== */
@media (max-width: 980px) {
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 760px) {
  .section { padding: 64px 0; }
  .nav-links, .nav-actions .btn-ghost { display: none; }
  .nav-toggle { display: grid; place-items: center; }
  .nav-links.open {
    display: flex;
    position: absolute;
    top: 66px; left: 0; right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    background: #fff;
    padding: 14px 24px 22px;
    border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow-md);
  }
  .nav-links.open a { padding: 12px 14px; }
  .grid-3, .grid-4, .grid-2 { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
}