/* ===== 北京知行智研科技有限公司 · 全局样式 ===== */
:root {
  --navy: #0F2A43;
  --navy-2: #16324f;
  --teal: #21B5A8;
  --teal-soft: #e6f7f5;
  --ink: #1f2937;
  --muted: #6b7280;
  --line: #e5e7eb;
  --bg: #f7f9fc;
  --white: #ffffff;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(15, 42, 67, 0.08);
  --maxw: 1120px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, -apple-system, "Segoe UI", sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

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

/* ===== 顶部导航 ===== */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav {
  display: flex; align-items: center; justify-content: space-between;
  height: 72px;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand img { width: 40px; height: 40px; display: block; }
.brand .name { font-weight: 700; font-size: 17px; color: var(--navy); letter-spacing: .5px; }
.brand .name small { display: block; font-size: 11px; color: var(--muted); font-weight: 500; letter-spacing: 1px; }

.nav-links { display: flex; gap: 6px; list-style: none; }
.nav-links a {
  display: inline-block; padding: 8px 16px; border-radius: 999px;
  font-size: 15px; color: var(--ink); transition: .2s;
}
.nav-links a:hover { background: var(--teal-soft); color: var(--navy); }
.nav-links a.active { background: var(--navy); color: #fff; }

.nav-toggle { display: none; background: none; border: 0; font-size: 26px; cursor: pointer; color: var(--navy); }

/* ===== Hero ===== */
.hero {
  background: linear-gradient(135deg, var(--navy) 0%, var(--navy-2) 60%, #0b2236 100%);
  color: #fff; padding: 84px 0 96px; position: relative; overflow: hidden;
}
.hero::after {
  content: ""; position: absolute; right: -80px; top: -80px;
  width: 360px; height: 360px; border-radius: 50%;
  background: radial-gradient(circle, rgba(33,181,168,.35), transparent 70%);
}
.hero .inner { display: flex; align-items: center; gap: 40px; position: relative; z-index: 1; }
.hero .logo-big { width: 132px; height: 132px; flex: 0 0 auto; filter: drop-shadow(0 12px 24px rgba(0,0,0,.35)); }
.hero h1 { font-size: 40px; line-height: 1.2; margin-bottom: 14px; }
.hero h1 span { color: var(--teal); }
.hero p { font-size: 18px; color: #cdd9e5; max-width: 560px; }
.hero .cta { margin-top: 28px; display: flex; gap: 14px; flex-wrap: wrap; }
.btn {
  display: inline-block; padding: 12px 26px; border-radius: 999px;
  font-size: 15px; font-weight: 600; transition: .2s; cursor: pointer;
}
.btn-primary { background: var(--teal); color: #042f2b; }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 10px 24px rgba(33,181,168,.4); }
.btn-ghost { border: 1px solid rgba(255,255,255,.4); color: #fff; }
.btn-ghost:hover { background: rgba(255,255,255,.1); }

/* ===== 通用区块 ===== */
.section { padding: 72px 0; }
.section.tight { padding: 48px 0; }
.section-title { font-size: 28px; color: var(--navy); margin-bottom: 8px; }
.section-sub { color: var(--muted); margin-bottom: 36px; }

.cards { display: grid; gap: 22px; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.card {
  background: var(--white); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 28px; box-shadow: var(--shadow); transition: .2s;
}
.card:hover { transform: translateY(-4px); border-color: var(--teal); }
.card .ico {
  width: 46px; height: 46px; border-radius: 12px; background: var(--teal-soft);
  display: grid; place-items: center; margin-bottom: 16px; color: var(--teal); font-weight: 700; font-size: 20px;
}
.card h3 { font-size: 19px; color: var(--navy); margin-bottom: 8px; }
.card p { color: var(--muted); font-size: 15px; }

/* 数据条 */
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px,1fr)); gap: 18px; }
.stat { background: var(--white); border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; text-align: center; }
.stat .num { font-size: 34px; font-weight: 800; color: var(--teal); }
.stat .label { color: var(--muted); font-size: 14px; margin-top: 4px; }

/* 时间线 / 列表 */
.list { display: grid; gap: 18px; }
.list .item { display: flex; gap: 16px; align-items: flex-start; }
.list .badge { flex: 0 0 auto; width: 44px; height: 44px; border-radius: 12px; background: var(--navy); color: #fff; display: grid; place-items: center; font-weight: 700; }
.list .item h4 { color: var(--navy); font-size: 17px; margin-bottom: 4px; }
.list .item p { color: var(--muted); font-size: 15px; }

/* 团队 */
.team-grid { display: grid; gap: 22px; grid-template-columns: repeat(auto-fit, minmax(220px,1fr)); }
.member { background: var(--white); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; text-align: center; box-shadow: var(--shadow); }
.member .avatar { width: 72px; height: 72px; margin: 0 auto 14px; border-radius: 50%; background: linear-gradient(135deg, var(--navy), var(--teal)); display: grid; place-items: center; color: #fff; font-size: 26px; font-weight: 700; }
.member h4 { color: var(--navy); }
.member .role { color: var(--teal); font-size: 14px; margin-bottom: 8px; }
.member p { color: var(--muted); font-size: 14px; }

/* 联系 */
.contact-grid { display: grid; grid-template-columns: 1.3fr 1fr; gap: 28px; }
.contact-info li { list-style: none; padding: 14px 0; border-bottom: 1px solid var(--line); display: flex; gap: 12px; }
.contact-info li b { color: var(--navy); width: 84px; flex: 0 0 auto; }
.contact-info li span { color: var(--muted); }
.map-box { background: var(--navy); border-radius: var(--radius); min-height: 220px; display: grid; place-items: center; color: #cdd9e5; }

/* 页脚 */
.footer { background: var(--navy); color: #cdd9e5; padding: 40px 0; }
.footer .container { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 20px; }
.footer a:hover { color: var(--teal); }
.footer .copy { font-size: 13px; color: #8da3b8; }
.footer .copy a { color: #8da3b8; text-decoration: underline; text-underline-offset: 3px; }
.footer .copy a:hover { color: var(--teal); }

/* 响应式 */
@media (max-width: 820px) {
  .nav-links { display: none; position: absolute; top: 72px; left: 0; right: 0; flex-direction: column; background: #fff; padding: 12px 24px; border-bottom: 1px solid var(--line); }
  .nav-links.open { display: flex; }
  .nav-toggle { display: block; }
  .hero .inner { flex-direction: column; text-align: center; }
  .hero p, .hero h1 { text-align: center; }
  .contact-grid { grid-template-columns: 1fr; }
}