/* =========================================================
   智核未来官网 · 样式表 V5
   全宽分区 / 居中式 Hero / 图标特性网格 / 服务流程 / 深色页脚
   主色 #014DB2 → #001645，暖白画布 #F9F9F9
   ========================================================= */
:root {
  --blue: #014DB2;
  --blue-dark: #001645;
  --ink: #111827;
  --ink-2: #4B5563;
  --ink-3: #6B7280;
  --ink-4: #9CA3AF;
  --bg: #F9F9F9;
  --card: #FFFFFF;
  --tint: #EAF1FB;
  --line: #E5EAF1;
  --shadow: 0 2px 8px rgba(1, 77, 178, 0.06);
  --shadow-lg: 0 12px 28px rgba(1, 77, 178, 0.10);
  --radius: 24px;
  --radius-sm: 16px;
  --container: 1160px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; overflow-x: clip; }
body {
  font-family: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", "Source Han Sans CN", sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.7;
  overflow-x: clip;
  -webkit-font-smoothing: antialiased;
}
a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }
h1, h2, h3 { line-height: 1.35; }
ul, ol { list-style: none; }

:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 2px;
  border-radius: 6px;
}

/* 跳转链接（键盘可达性） */
.skip-link {
  position: absolute; left: 12px; top: -60px;
  z-index: 300;
  background: var(--blue); color: #fff;
  padding: 10px 18px; border-radius: 10px;
  font-size: 14px;
  transition: top .18s ease;
}
.skip-link:focus { top: 12px; }

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

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  border: none; cursor: pointer;
  border-radius: 999px;
  font-size: 15px; font-family: inherit;
  padding: 13px 30px;
  transition: transform .15s ease, box-shadow .15s ease, opacity .15s ease;
}
.btn:hover { transform: translateY(-1px); box-shadow: var(--shadow-lg); }
.btn-sm { padding: 9px 22px; font-size: 14px; }
.btn-primary { background: var(--blue); color: #fff; }
.btn-white { background: #fff; color: var(--blue); font-weight: 500; }
.btn-ghost {
  background: rgba(255,255,255,.10);
  border: 1px solid rgba(255,255,255,.4);
  color: #fff;
}

/* ---------- 顶部导航 ---------- */
.site-header {
  background: rgba(255,255,255,.92);
  backdrop-filter: saturate(160%) blur(12px);
  box-shadow: 0 1px 0 rgba(1, 28, 69, .06);
  position: sticky; top: 0; z-index: 100;
  transition: box-shadow .2s ease;
}
.site-header.is-scrolled { box-shadow: 0 6px 20px rgba(1, 40, 100, .08); }
.header-inner {
  position: relative;
  max-width: var(--container); margin: 0 auto;
  padding: 14px 24px;
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
  width: 42px; height: 42px; border-radius: 13px;
  background: linear-gradient(140deg, var(--blue) 0%, #0A62D6 100%);
  display: inline-flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}
.brand-text { display: flex; flex-direction: column; line-height: 1.3; }
.brand-text strong { font-size: 19px; }
.brand-text small { font-size: 11px; color: var(--ink-3); }

.top-nav { display: flex; align-items: center; gap: 28px; }
.top-nav a { font-size: 15px; color: var(--ink-2); transition: color .15s; position: relative; }
.top-nav a:hover { color: var(--blue); }
.top-nav a.active { color: var(--blue); font-weight: 500; }
.top-nav a.active::after {
  content: ""; position: absolute; left: 50%; bottom: -7px;
  width: 16px; height: 2px; border-radius: 2px;
  background: var(--blue); transform: translateX(-50%);
}

/* 移动端菜单按钮 */
.nav-toggle {
  display: none;
  width: 42px; height: 42px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fff;
  cursor: pointer;
  flex-direction: column; align-items: center; justify-content: center; gap: 4px;
}
.nav-toggle span {
  display: block; width: 18px; height: 2px; border-radius: 2px;
  background: var(--ink); transition: transform .2s ease, opacity .2s ease;
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  overflow: hidden;
  background: linear-gradient(160deg, #0A62D6 0%, var(--blue) 38%, var(--blue-dark) 100%);
  color: #fff;
}
.hero-bg {
  position: absolute; inset: 0;
  background:
    radial-gradient(560px 300px at 82% 8%, rgba(143,184,245,.28), transparent 65%),
    radial-gradient(480px 280px at 12% 90%, rgba(52,211,153,.10), transparent 60%),
    radial-gradient(300px 300px at 95% 75%, rgba(255,255,255,.08), transparent 60%);
}
.hero-content {
  position: relative;
  max-width: var(--container); margin: 0 auto;
  padding: 84px 24px 84px;
  display: flex; flex-direction: column; align-items: center;
  text-align: center; gap: 20px;
}
.hero-badge {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 7px 18px; border-radius: 999px;
  background: rgba(255,255,255,.14);
  border: 1px solid rgba(255,255,255,.22);
  font-size: 13px;
}
.hero-badge .dot { width: 8px; height: 8px; border-radius: 50%; background: #34D399; }
.hero h1 { font-size: 46px; font-weight: 900; letter-spacing: 1px; }
.hero-content > p { font-size: 16px; color: #C9D8F2; max-width: 680px; }
.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; justify-content: center; margin-top: 6px; }
.hero-visual {
  margin-top: 28px;
  width: min(880px, 100%);
  border-radius: var(--radius);
  overflow: hidden;
  background: #0A2B66;
  box-shadow: 0 24px 60px rgba(0, 12, 40, .45);
}
.hero-visual img { width: 100%; height: auto; aspect-ratio: 16 / 7; object-fit: cover; }

/* ---------- 服务流程 ---------- */
.process-wrap {
  max-width: var(--container); margin: -42px auto 0;
  padding: 0 24px; position: relative; z-index: 2;
}
.process {
  display: grid; grid-template-columns: repeat(4, 1fr);
  gap: 0;
  background: var(--card);
  border-radius: 20px;
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}
.process-step {
  padding: 24px 26px;
  display: flex; flex-direction: column; gap: 4px;
  position: relative;
}
.process-step + .process-step::before {
  content: ""; position: absolute; left: 0; top: 26px; bottom: 26px;
  width: 1px; background: var(--line);
}
.step-no {
  font-size: 12px; font-weight: 700; letter-spacing: 1px;
  color: var(--blue); opacity: .55;
}
.process-step strong { font-size: 15px; }
.process-step span:last-child { font-size: 13px; color: var(--ink-3); }

/* ---------- 通用区块 ---------- */
.section { max-width: var(--container); margin: 0 auto; padding: 60px 24px 0; }
.section:last-of-type { padding-bottom: 68px; }
.section-head { margin-bottom: 28px; }
.section-head h2 { font-size: 30px; }
.section-head p { font-size: 14px; color: var(--ink-3); margin-top: 8px; }

/* ---------- 核心业务：图标特性网格 ---------- */
.direction-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}
.dir-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 28px 24px;
  display: flex; flex-direction: column; gap: 10px;
  transition: transform .18s ease, box-shadow .18s ease, border-color .18s ease;
}
.dir-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: transparent; }
.dir-icon {
  width: 46px; height: 46px; border-radius: 14px;
  background: var(--tint); color: var(--blue);
  display: inline-flex; align-items: center; justify-content: center;
}
.dir-card h3 { font-size: 17px; }
.dir-card p { font-size: 13.5px; color: var(--ink-3); }

/* ---------- 服务对象 ---------- */
.client-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}
.client-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 20px 26px;
  display: flex; align-items: baseline; gap: 16px;
  transition: border-color .18s ease, box-shadow .18s ease;
}
.client-card:hover { border-color: #C9DAF3; box-shadow: var(--shadow); }
.client-card strong { font-size: 15px; flex-shrink: 0; }
.client-card span { font-size: 13px; color: var(--ink-3); }

/* ---------- 视频区 ---------- */
.section-head { display: flex; justify-content: space-between; align-items: flex-end; gap: 20px; flex-wrap: wrap; }
.chips { display: flex; gap: 10px; flex-wrap: wrap; }
.chip {
  padding: 8px 18px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: #fff;
  font-size: 13px; font-family: inherit;
  color: var(--ink-2);
  cursor: pointer;
  transition: all .15s;
}
.chip:hover { border-color: var(--blue); color: var(--blue); }
.chip.is-active { background: var(--blue); border-color: var(--blue); color: #fff; }

.video-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}
.video-card {
  background: var(--card);
  border-radius: 18px;
  padding: 12px;
  box-shadow: var(--shadow);
  display: flex; flex-direction: column; gap: 10px;
  cursor: pointer;
  text-align: left;
  border: none; font-family: inherit;
  transition: transform .18s ease, box-shadow .18s ease;
}
.video-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); }

.video-thumb {
  position: relative;
  aspect-ratio: 16 / 9;
  border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, var(--blue) 0%, var(--blue-dark) 100%);
  overflow: hidden;
}
.video-thumb img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; }
.video-card:nth-child(3n+2) .video-thumb { background: linear-gradient(135deg, #0A62D6 0%, #012A66 100%); }
.video-card:nth-child(3n) .video-thumb { background: linear-gradient(135deg, #1E4FC4 0%, #021030 100%); }

.play-btn {
  position: relative;
  width: 50px; height: 50px; border-radius: 50%;
  background: rgba(255,255,255,.92);
  display: flex; align-items: center; justify-content: center;
  transition: transform .15s;
}
.video-card:hover .play-btn { transform: scale(1.08); }

.video-duration {
  position: absolute; right: 10px; bottom: 10px;
  padding: 3px 10px; border-radius: 999px;
  background: rgba(0,0,0,.45);
  color: #fff; font-size: 12px;
}
.video-card h3 { font-size: 15px; font-weight: 600; }
.video-meta { display: flex; justify-content: space-between; font-size: 12px; }
.video-meta .cat { color: var(--ink-4); }
.video-meta .dur { color: var(--blue); font-weight: 500; }

.video-skeleton {
  height: 220px;
  border-radius: 18px;
  background: linear-gradient(100deg, #F1F4F8 30%, #E7ECF3 50%, #F1F4F8 70%);
  background-size: 200% 100%;
  animation: shimmer 1.4s infinite linear;
}
@keyframes shimmer { to { background-position: -200% 0; } }

.grid-empty { color: var(--ink-3); font-size: 14px; padding: 8px 0; }

/* ---------- 关于 ---------- */
.about {
  background: var(--card);
  border-radius: var(--radius);
  padding: 40px 44px;
  box-shadow: var(--shadow);
}
.about h2 { font-size: 26px; margin-bottom: 12px; }
.about p { color: var(--ink-3); font-size: 15px; max-width: 900px; margin-bottom: 8px; }

/* ---------- 页脚 ---------- */
.site-footer { background: var(--blue-dark); color: #fff; padding: 44px 0 36px; }
.footer-top {
  max-width: var(--container); margin: 0 auto; padding: 0 24px;
  display: flex; justify-content: space-between; align-items: flex-start;
  gap: 32px; flex-wrap: wrap;
}
.footer-brand strong { font-size: 16px; }
.footer-brand p { font-size: 12px; color: #8FA8D9; margin-top: 8px; }
.footer-links { display: flex; gap: 24px; flex-wrap: wrap; }
.footer-links a { font-size: 13px; color: #C9D8F2; }
.footer-links a:hover { color: #fff; }
.footer-divider { max-width: var(--container); margin: 20px auto; height: 1px; background: #12306B; }
.footer-bottom {
  max-width: var(--container); margin: 0 auto; padding: 0 24px;
  display: flex; justify-content: space-between; align-items: center;
  gap: 16px; flex-wrap: wrap;
  font-size: 12px; color: #6E8AC4;
}
.beian { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.beian a { color: #6E8AC4; }
.beian a:hover { color: #fff; }

/* ---------- 回到顶部 ---------- */
.to-top {
  position: fixed; right: 24px; bottom: 24px;
  width: 44px; height: 44px; border-radius: 50%;
  border: 1px solid var(--line);
  background: #fff; color: var(--blue);
  box-shadow: var(--shadow-lg);
  display: inline-flex; align-items: center; justify-content: center;
  cursor: pointer; z-index: 90;
  transition: transform .15s ease, opacity .2s ease;
}
.to-top[hidden] { display: none; }
.to-top:hover { transform: translateY(-2px); }

/* ---------- 滚动渐显（仅 JS 可用时启用，保证无 JS 内容可见） ---------- */
.js .reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity .55s ease, transform .55s ease;
}
.js .reveal.is-in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .reveal { opacity: 1; transform: none; transition: none; }
  .video-skeleton { animation: none; }
}

/* ---------- 视频弹层 ---------- */
.modal {
  position: fixed; inset: 0; z-index: 200;
  display: flex; align-items: center; justify-content: center;
  padding: 24px;
}
.modal[hidden] { display: none; }
.modal-backdrop { position: absolute; inset: 0; background: rgba(0, 12, 32, .72); }
.modal-panel {
  position: relative;
  width: min(960px, 100%);
  max-height: 90vh;
  overflow: auto;
  background: #0B1220;
  border-radius: 20px;
  box-shadow: 0 24px 60px rgba(0,0,0,.45);
}
.modal-close {
  position: absolute; top: 12px; right: 14px;
  width: 36px; height: 36px;
  border: none; border-radius: 50%;
  background: rgba(255,255,255,.14);
  color: #fff; font-size: 22px; line-height: 1;
  cursor: pointer; z-index: 2;
}
.modal-close:hover { background: rgba(255,255,255,.26); }
.modal-player { background: #000; aspect-ratio: 16 / 9; }
.modal-player video { width: 100%; height: 100%; display: block; background: #000; }
.modal-body { padding: 20px 24px 24px; color: #fff; }
.modal-body h3 { font-size: 18px; margin-bottom: 6px; }
.modal-body p { font-size: 14px; color: #9FB0CC; }

body.modal-open { overflow: hidden; }

/* ---------- 响应式 ---------- */
@media (max-width: 1180px) {
  .video-grid { grid-template-columns: repeat(2, 1fr); }
  .direction-grid { grid-template-columns: repeat(2, 1fr); }
  .top-nav { gap: 20px; }
  .top-nav a { font-size: 14px; }
}
@media (max-width: 1024px) {
  .hero h1 { font-size: 38px; }
  .hero-content { padding: 64px 24px 72px; }
  .process { grid-template-columns: repeat(2, 1fr); }
  .process-step:nth-child(3)::before { display: none; }
  .process-step:nth-child(n+3) { border-top: 1px solid var(--line); }
}
@media (max-width: 820px) {
  .nav-toggle { display: inline-flex; }
  .top-nav {
    position: absolute; left: 0; right: 0; top: 100%;
    flex-direction: column; align-items: stretch; gap: 0;
    background: #fff;
    padding: 6px 20px 14px;
    box-shadow: 0 14px 24px rgba(1, 40, 100, .10);
    display: none;
  }
  .top-nav.is-open { display: flex; }
  .top-nav a {
    padding: 13px 2px;
    border-bottom: 1px solid var(--line);
    font-size: 15px;
  }
  .top-nav a:last-child { border-bottom: none; }
  .top-nav a.active::after { display: none; }
  .client-grid { grid-template-columns: 1fr; }
  .hero h1 { font-size: 31px; }
  .hero-content > p { font-size: 15px; }
  .about { padding: 28px 24px; }
  .footer-bottom { justify-content: center; text-align: center; }
  .modal-body { padding: 16px 18px 20px; }
  .section { padding-top: 46px; }
  .section-head h2 { font-size: 25px; }
}
@media (max-width: 640px) {
  .direction-grid, .video-grid { grid-template-columns: 1fr; }
  .process { grid-template-columns: 1fr; }
  .process-step + .process-step::before { display: none; }
  .process-step + .process-step { border-top: 1px solid var(--line); }
  .client-card { flex-direction: column; gap: 4px; align-items: flex-start; }
  .hero-actions .btn { flex: 1 1 auto; }
  .to-top { right: 16px; bottom: 16px; }
}