/* ============================================
   云上甘露园 · 智慧园区汇报站 / 门户站 共用设计系统
   主题：北京公交集团 VI —— 公交红 + 都市灰
   ============================================ */
:root {
  --bjt-red: #d71920;
  --bjt-red-dark: #a5131a;
  --bjt-red-light: #fbe9ea;
  --bjt-gray-900: #2b2b2b;
  --bjt-gray-700: #4d4d4d;
  --bjt-gray-500: #8a8a8a;
  --bjt-gray-200: #e6e6e6;
  --bjt-gray-100: #f5f5f5;
  --ink: #1f2329;
  --bg: #ffffff;
  --radius: 14px;
  --shadow-sm: 0 2px 10px rgba(0, 0, 0, .06);
  --shadow-md: 0 10px 30px rgba(0, 0, 0, .10);
  --shadow-lg: 0 24px 60px rgba(0, 0, 0, .16);
  --font: "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans SC", 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;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

.container { width: min(1200px, 92vw); margin: 0 auto; }
.section { padding: 88px 0; }
.section--gray { background: var(--bjt-gray-100); }
.section--dark { background: var(--bjt-gray-900); color: #eee; }

/* ---------- 顶部导航 ---------- */
.nav {
  position: fixed; inset: 0 0 auto 0; z-index: 100;
  backdrop-filter: blur(12px);
  background: rgba(255, 255, 255, .88);
  border-bottom: 1px solid rgba(0, 0, 0, .06);
  transition: box-shadow .3s;
}
.nav.scrolled { box-shadow: var(--shadow-sm); }
.nav__inner { display: flex; align-items: center; gap: 28px; height: 64px; }
.nav__brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 17px; }
.nav__brand img { height: 34px; width: auto; }
.nav__brand .sub { color: var(--bjt-red); font-size: 12px; font-weight: 600; letter-spacing: 2px; }
.nav__links { margin-left: auto; display: flex; gap: 4px; align-items: center; }
.nav__links a {
  padding: 8px 14px; border-radius: 8px; font-size: 14.5px; color: var(--bjt-gray-700);
  transition: all .2s;
}
.nav__links a:hover { color: var(--bjt-red); background: var(--bjt-red-light); }
.nav__links a.cta {
  background: var(--bjt-red); color: #fff; font-weight: 600;
}
.nav__links a.cta:hover { background: var(--bjt-red-dark); }
.nav__toggle { display: none; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 13px 28px; border-radius: 999px; font-weight: 600; font-size: 15px;
  transition: transform .2s, box-shadow .2s, background .2s;
  cursor: pointer; border: 0;
}
.btn--primary { background: var(--bjt-red); color: #fff; box-shadow: 0 8px 20px rgba(215, 25, 32, .35); }
.btn--primary:hover { background: var(--bjt-red-dark); transform: translateY(-2px); }
.btn--ghost { border: 1.5px solid rgba(255, 255, 255, .7); color: #fff; }
.btn--ghost:hover { background: rgba(255, 255, 255, .12); }
.btn--outline { border: 1.5px solid var(--bjt-red); color: var(--bjt-red); background: #fff; }
.btn--outline:hover { background: var(--bjt-red-light); }

/* ---------- 标题 ---------- */
.kicker {
  display: inline-flex; align-items: center; gap: 8px;
  color: var(--bjt-red); font-weight: 700; letter-spacing: 3px; font-size: 13px;
  text-transform: uppercase;
}
.kicker::before { content: ""; width: 26px; height: 3px; background: var(--bjt-red); border-radius: 2px; }
.h2 { font-size: clamp(26px, 3.4vw, 40px); font-weight: 800; line-height: 1.3; margin: 14px 0 10px; }
.lead { color: var(--bjt-gray-500); font-size: 16.5px; max-width: 760px; }
.section--dark .lead { color: #b9b9b9; }

/* ---------- 滚动显现动画 ---------- */
.reveal { opacity: 0; transform: translateY(34px); transition: opacity .8s ease, transform .8s cubic-bezier(.2, .7, .3, 1); }
.reveal.in { opacity: 1; transform: none; }
.reveal[data-delay="1"] { transition-delay: .12s; }
.reveal[data-delay="2"] { transition-delay: .24s; }
.reveal[data-delay="3"] { transition-delay: .36s; }

/* ---------- 页脚 ---------- */
.footer { background: var(--bjt-gray-900); color: #9a9a9a; padding: 46px 0 30px; font-size: 13.5px; }
.footer a:hover { color: #fff; }
.footer__grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 32px; margin-bottom: 30px; }
.footer h5 { color: #fff; font-size: 14px; margin-bottom: 12px; }
.footer li { margin-bottom: 8px; }
.footer__brand { display: flex; align-items: center; gap: 10px; color: #fff; font-weight: 700; margin-bottom: 12px; }
.footer__brand img { height: 30px; filter: brightness(0) invert(1); opacity: .92; }
.footer__copy { border-top: 1px solid rgba(255, 255, 255, .1); padding-top: 20px; text-align: center; }

@media (max-width: 860px) {
  .section { padding: 60px 0; }
  .footer__grid { grid-template-columns: 1fr 1fr; }
  .nav__links { display: none; }
}