/* ===== 上海中天智擎人工智能科技有限公司 · 欧美风格样式 ===== */
:root {
  --bg: #ffffff;
  --bg-soft: #f8fafc;
  --bg-dark: #0f172a;
  --bg-dark-2: #1e293b;
  --ink: #0f172a;
  --ink-soft: #475569;
  --line: #e2e8f0;
  --brand: #6366f1;
  --brand-2: #8b5cf6;
  --accent: #0ea5e9;
  --radius: 16px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, .06), 0 2px 8px rgba(15, 23, 42, .05);
  --shadow-md: 0 10px 30px rgba(15, 23, 42, .08);
  --maxw: 1140px;
  --font: 'Inter', 'Segoe UI', system-ui, -apple-system, 'Helvetica Neue', Arial, 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.gradient-text {
  background: linear-gradient(120deg, var(--brand), var(--brand-2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}

/* ===== 导航 ===== */
.site-nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .82);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 17px; letter-spacing: .2px; }
.brand .logo {
  width: 34px; height: 34px; border-radius: 9px;
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  display: grid; place-items: center; color: #fff; font-weight: 800; font-size: 15px;
}
.nav-links { display: flex; gap: 6px; align-items: center; }
.nav-links a {
  padding: 9px 16px; border-radius: 999px; color: var(--ink-soft);
  font-weight: 500; font-size: 15px; transition: .2s;
}
.nav-links a:hover { color: var(--ink); background: var(--bg-soft); }
.nav-links a.active { color: #fff; background: linear-gradient(135deg, var(--brand), var(--brand-2)); }

/* ===== 按钮 ===== */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 24px; border-radius: 999px; font-weight: 600; font-size: 15px;
  border: 1px solid transparent; cursor: pointer; transition: .2s;
}
.btn-primary { background: linear-gradient(135deg, var(--brand), var(--brand-2)); color: #fff; box-shadow: var(--shadow-md); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 16px 36px rgba(99, 102, 241, .35); }
.btn-ghost { background: #fff; color: var(--ink); border-color: var(--line); }
.btn-ghost:hover { border-color: var(--brand); color: var(--brand); }

/* ===== Hero ===== */
.hero { position: relative; overflow: hidden; padding: 96px 0 84px; }
.hero::before {
  content: ""; position: absolute; inset: 0; z-index: -1;
  background:
    radial-gradient(60% 60% at 80% 0%, rgba(139, 92, 246, .12), transparent 60%),
    radial-gradient(50% 50% at 0% 30%, rgba(14, 165, 233, .10), transparent 60%),
    var(--bg-soft);
}
.hero .eyebrow {
  display: inline-block; font-size: 13px; font-weight: 600; letter-spacing: 1.5px;
  text-transform: uppercase; color: var(--brand); margin-bottom: 18px;
}
.hero h1 { font-size: clamp(34px, 5vw, 58px); line-height: 1.1; font-weight: 800; letter-spacing: -.5px; }
.hero p.lead { margin: 22px auto 0; max-width: 620px; font-size: 18px; color: var(--ink-soft); }
.hero .actions { margin-top: 34px; display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }

/* ===== 区块 ===== */
.section { padding: 84px 0; }
.section.soft { background: var(--bg-soft); }
.section-head { text-align: center; max-width: 680px; margin: 0 auto 52px; }
.section-head .eyebrow { font-size: 13px; font-weight: 700; letter-spacing: 1.5px; text-transform: uppercase; color: var(--brand); }
.section-head h2 { font-size: clamp(28px, 3.6vw, 40px); font-weight: 800; margin-top: 12px; letter-spacing: -.5px; }
.section-head p { margin-top: 14px; color: var(--ink-soft); font-size: 17px; }

/* ===== 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); }
.card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 30px; box-shadow: var(--shadow-sm); transition: .25s;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); border-color: #cbd5f5; }
.card .icon {
  width: 50px; height: 50px; border-radius: 12px; display: grid; place-items: center;
  font-size: 22px; margin-bottom: 18px;
  background: linear-gradient(135deg, rgba(99,102,241,.12), rgba(139,92,246,.12));
}
.card h3 { font-size: 19px; font-weight: 700; margin-bottom: 10px; }
.card p { color: var(--ink-soft); font-size: 15px; }

/* ===== 介绍页 ===== */
.prose { max-width: 880px; margin: 0 auto; }
.prose p { color: var(--ink-soft); margin-bottom: 18px; font-size: 16.5px; }
.prose h3 { font-size: 22px; font-weight: 700; margin: 34px 0 14px; }
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; margin-top: 46px; }
.stat { text-align: center; padding: 26px 16px; border-radius: var(--radius); background: var(--bg-soft); border: 1px solid var(--line); }
.stat .num { font-size: 34px; font-weight: 800; background: linear-gradient(120deg, var(--brand), var(--brand-2)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.stat .label { color: var(--ink-soft); font-size: 14px; margin-top: 6px; }

/* ===== 联系页 ===== */
.contact-wrap { display: grid; grid-template-columns: 1.1fr .9fr; gap: 40px; align-items: start; }
.form { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 34px; box-shadow: var(--shadow-sm); }
.field { margin-bottom: 18px; }
.field label { display: block; font-weight: 600; font-size: 14px; margin-bottom: 8px; }
.field input, .field textarea {
  width: 100%; padding: 12px 14px; border: 1px solid var(--line); border-radius: 10px;
  font-family: inherit; font-size: 15px; color: var(--ink); background: var(--bg-soft); transition: .2s;
}
.field input:focus, .field textarea:focus { outline: none; border-color: var(--brand); background: #fff; box-shadow: 0 0 0 3px rgba(99,102,241,.15); }
.field textarea { min-height: 130px; resize: vertical; }
.info-card { background: linear-gradient(160deg, var(--bg-dark), var(--bg-dark-2)); color: #fff; border-radius: var(--radius); padding: 34px; }
.info-card h3 { font-size: 20px; margin-bottom: 18px; }
.info-card .row { display: flex; gap: 12px; padding: 12px 0; border-bottom: 1px solid rgba(255,255,255,.08); font-size: 15px; }
.info-card .row:last-child { border-bottom: 0; }
.info-card .row .k { color: #94a3b8; min-width: 64px; }
.note { font-size: 13px; color: var(--ink-soft); margin-top: 14px; }

/* ===== 页脚 ===== */
.site-footer { background: var(--bg-dark); color: #cbd5e1; padding: 56px 0 28px; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 40px; }
.site-footer h4 { color: #fff; font-size: 15px; margin-bottom: 16px; }
.site-footer a { color: #cbd5e1; font-size: 14px; display: block; padding: 5px 0; }
.site-footer a:hover { color: #fff; }
.site-footer p { font-size: 14px; color: #94a3b8; max-width: 320px; }
.footer-bottom { border-top: 1px solid rgba(255,255,255,.08); margin-top: 40px; padding-top: 22px; text-align: center; font-size: 13px; color: #94a3b8; }

/* ===== 响应式 ===== */
@media (max-width: 900px) {
  .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .contact-wrap { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .nav-links { gap: 2px; }
  .nav-links a { padding: 8px 11px; font-size: 14px; }
}
@media (max-width: 560px) {
  .stats { grid-template-columns: 1fr; }
  .hero { padding: 64px 0 56px; }
}