/* ============================================================
   代维科技 · 官网样式（冷灰蓝配色）
   ============================================================ */
:root {
  --paper: #F4F6F9;
  --paper-soft: #ECF0F4;
  --surface: #FFFFFF;
  --ink: #1F2937;
  --ink-soft: #4B5563;
  --ink-faint: #87919E;
  --accent: #3D6B96;
  --accent-deep: #2A4A6E;
  --tint: #E7EEF5;
  --tint-strong: #D4E0EB;
  --line: #E0E6EE;
  --serif: "PingFang SC", "Microsoft YaHei UI", "Microsoft YaHei", "Noto Sans SC", "Source Han Sans SC", "SimHei", "黑体", sans-serif;
  --sans: "PingFang SC", "Microsoft YaHei UI", "Microsoft YaHei", "Noto Sans SC", "Source Han Sans SC", "SimHei", "黑体", sans-serif;
  --shadow: 0 14px 42px -20px rgba(40, 49, 59, 0.26);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--sans); background: var(--paper); color: var(--ink);
  line-height: 1.7; font-weight: 400; -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility;
}
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img { display: block; max-width: 100%; }
.container { width: min(1180px, 92%); margin: 0 auto; }

/* ---------- Nav ---------- */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 60;
  transition: background .35s ease, box-shadow .35s ease, border-color .35s ease;
  border-bottom: 1px solid transparent;
}
.nav.scrolled {
  background: rgba(245, 247, 250, .9); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
  border-color: var(--line); box-shadow: 0 6px 24px -18px rgba(40,49,59,.35);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 72px; }
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark { width: 40px; height: 40px; border-radius: 11px; background: var(--accent-deep); display: grid; place-items: center; color: #fff; flex: none; }
.brand-mark svg { width: 22px; height: 22px; }
.brand-name { font-family: var(--serif); font-weight: 600; font-size: 20px; letter-spacing: 0; }
.brand-sub { font-size: 10px; color: var(--ink-faint); letter-spacing: 3px; }

.nav-links { display: flex; align-items: center; gap: 30px; }
.nav-links a { font-size: 15px; font-weight: 500; color: var(--ink-soft); position: relative; padding: 6px 0; letter-spacing: 0; transition: color .25s ease; }
.nav-links a::after { content: ""; position: absolute; left: 0; bottom: 0; width: 0; height: 2px; background: var(--accent); transition: width .25s ease; }
.nav-links a:hover { color: var(--ink); }
.nav-links a:hover::after, .nav-links a.active::after { width: 100%; }
.nav-links a.active { color: var(--ink); }
.nav-cta { font-size: 14px; padding: 10px 22px; border: 1px solid var(--accent-deep); color: var(--accent-deep); border-radius: 100px; transition: all .25s ease; background: transparent; }
.nav-cta:hover { background: var(--accent-deep); color: #fff; }
.menu-toggle { display: none; background: none; border: none; cursor: pointer; padding: 8px; color: var(--ink); }

/* ---------- Hero (首页) ---------- */
.hero { position: relative; padding: 168px 0 110px; overflow: hidden; }
.hero-bg {
  position: absolute; inset: 0; z-index: -1;
  background:
    radial-gradient(58% 52% at 78% 16%, var(--tint) 0%, transparent 70%),
    radial-gradient(48% 48% at 12% 84%, var(--paper-soft) 0%, transparent 72%);
}
.hero-grid {
  position: absolute; inset: 0; z-index: -2; opacity: .5;
  background-image: linear-gradient(var(--line) 1px, transparent 1px), linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 52px 52px;
  mask-image: radial-gradient(72% 72% at 50% 28%, #000 0%, transparent 100%);
  -webkit-mask-image: radial-gradient(72% 72% at 50% 28%, #000 0%, transparent 100%);
}
.eyebrow { display: inline-flex; align-items: center; gap: 10px; font-size: 13px; letter-spacing: 3px; color: var(--accent-deep); }
.eyebrow::before { content: ""; width: 28px; height: 1px; background: var(--accent); }
.hero h1 { font-family: var(--serif); font-weight: 700; font-size: clamp(28px, 3.8vw, 42px); line-height: 1.4; margin: 24px 0 16px; letter-spacing: 0; color: var(--ink); }
.hero h1 em { font-style: normal; color: var(--accent-deep); }
.hero-tagline { font-size: 14px; letter-spacing: 1px; color: var(--accent-deep); font-weight: 400; margin: 0 0 28px; }
.hero-lead { max-width: 660px; font-size: 16px; color: var(--ink-soft); margin-bottom: 34px; }
.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; }

.btn { display: inline-flex; align-items: center; gap: 9px; padding: 14px 30px; border-radius: 100px; font-size: 15px; letter-spacing: .5px; cursor: pointer; transition: all .25s ease; border: 1px solid transparent; }
.btn-primary { background: var(--accent-deep); color: #fff; box-shadow: 0 14px 30px -14px rgba(65,94,120,.55); }
.btn-primary:hover { background: var(--accent); transform: translateY(-2px); }
.btn-ghost { border-color: var(--line); color: var(--ink); background: rgba(255,255,255,.55); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent-deep); }

.hero-stats { display: grid; grid-template-columns: repeat(5, 1fr); gap: 28px; margin-top: 74px; padding-top: 34px; border-top: 1px solid var(--line); }
.stat .num { font-family: var(--serif); font-size: 30px; font-weight: 700; color: var(--ink); line-height: 1; }
.stat .num small { font-size: 16px; color: var(--accent); margin-left: 2px; }
.stat .lbl { font-size: 13px; color: var(--ink-faint); margin-top: 9px; letter-spacing: 1px; }

/* ---------- 内页 Banner ---------- */
.page-banner { position: relative; padding: 156px 0 72px; overflow: hidden; }
.page-banner::before {
  content: ""; position: absolute; inset: 0; z-index: -1;
  background:
    radial-gradient(55% 60% at 82% 10%, var(--tint) 0%, transparent 70%),
    radial-gradient(45% 50% at 8% 90%, var(--paper-soft) 0%, transparent 72%);
}
.page-banner h1 { font-family: var(--serif); font-weight: 700; font-size: clamp(24px, 3.2vw, 34px); line-height: 1.35; margin: 16px 0 14px; letter-spacing: 0; }
.page-banner .sub { max-width: 680px; font-size: 16.5px; color: var(--ink-soft); }

/* ---------- Section 通用 ---------- */
section { padding: 84px 0; }
.alt { background: var(--paper-soft); }
.section-head { max-width: 680px; margin-bottom: 48px; }
.section-head.center { margin-left: auto; margin-right: auto; text-align: center; }
.section-head.center .eyebrow { justify-content: center; }
.section-head.center .eyebrow::before { display: none; }
.section-title { font-family: var(--serif); font-size: clamp(21px, 2.6vw, 28px); font-weight: 700; line-height: 1.4; margin: 14px 0 12px; letter-spacing: 0; }
.section-desc { color: var(--ink-soft); font-size: 15.5px; }

/* ---------- 通用卡片 / 区块 ---------- */
.group-title { display: flex; align-items: center; gap: 12px; font-family: var(--serif); font-size: 19px; font-weight: 700; margin-bottom: 20px; color: var(--ink); }
.group-title .bar { width: 3px; height: 20px; background: var(--accent); border-radius: 2px; }
.group-title small { font-size: 12px; font-weight: 400; color: var(--ink-faint); letter-spacing: 2px; }

/* About */
.about-lead { display: grid; grid-template-columns: 1.05fr 1fr; gap: 56px; align-items: center; margin-bottom: 60px; }
.about-visual { background: linear-gradient(135deg, var(--accent-deep), var(--accent)); border-radius: 24px; padding: 44px; color: #fff; position: relative; overflow: hidden; }
.about-visual::after { content: ""; position: absolute; right: -70px; top: -70px; width: 220px; height: 220px; border: 1px solid rgba(255,255,255,.18); border-radius: 50%; }
.about-visual::before { content: ""; position: absolute; right: 30px; bottom: -110px; width: 260px; height: 260px; border: 1px solid rgba(255,255,255,.14); border-radius: 50%; }
.about-visual .kicker { font-size: 12px; letter-spacing: 4px; opacity: .78; }
.about-visual h3 { font-family: var(--serif); font-size: 24px; font-weight: 700; line-height: 1.45; margin: 14px 0 16px; }
.about-visual p { font-size: 14.5px; opacity: .92; }
.about-copy p { color: var(--ink-soft); font-size: 15.5px; margin-bottom: 16px; }
.about-facts { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 24px; }
.fact { display: flex; gap: 12px; align-items: flex-start; background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 16px 18px; }
.fact .ico { width: 26px; height: 26px; border-radius: 8px; background: var(--tint); color: var(--accent-deep); display: grid; place-items: center; flex: none; }
.fact .ico svg { width: 15px; height: 15px; }
.fact b { display: block; font-weight: 500; font-size: 14.5px; }
.fact span { font-size: 12.5px; color: var(--ink-faint); }

.about-grid { display: grid; grid-template-columns: 1.25fr 1fr; gap: 56px; }
.timeline { position: relative; padding-left: 34px; max-width: 880px; }
.timeline::before { content: ""; position: absolute; left: 9px; top: 8px; bottom: 8px; width: 1px; background: linear-gradient(var(--accent), var(--line)); }
.tl-item { position: relative; padding-bottom: 24px; }
.tl-item::before { content: ""; position: absolute; left: -30px; top: 7px; width: 9px; height: 9px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 0 4px var(--tint); }
.tl-item:last-child { padding-bottom: 0; }
.tl-item .year { font-family: var(--serif); font-size: 15px; font-weight: 700; color: var(--accent-deep); }
.tl-item .txt { font-size: 13.5px; color: var(--ink-soft); margin-top: 2px; }

.network { display: flex; flex-wrap: wrap; gap: 10px; }
.network span { background: var(--surface); border: 1px solid var(--line); border-radius: 100px; padding: 8px 18px; font-size: 13px; color: var(--ink-soft); }
.network span.hq { background: var(--accent-deep); color: #fff; border-color: var(--accent-deep); }
.info-chip { margin-top: 24px; padding: 18px 20px; background: var(--surface); border: 1px solid var(--line); border-radius: 14px; font-size: 13.5px; color: var(--ink-soft); }

/* 三大方向 */
.pillars { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.pillar { background: var(--surface); border: 1px solid var(--line); border-radius: 20px; padding: 36px 32px; transition: transform .3s ease, box-shadow .3s ease, border-color .3s ease; position: relative; overflow: hidden; }
.pillar:hover { transform: translateY(-6px); box-shadow: var(--shadow); border-color: var(--tint-strong); }
.pillar-icon { width: 52px; height: 52px; border-radius: 14px; background: var(--tint); color: var(--accent-deep); display: grid; place-items: center; margin-bottom: 22px; }
.pillar-icon svg { width: 26px; height: 26px; }
.pillar .idx { position: absolute; top: 30px; right: 30px; font-family: var(--serif); font-size: 13px; color: var(--ink-faint); letter-spacing: 2px; }
.pillar h3 { font-family: var(--serif); font-size: 21px; font-weight: 700; margin-bottom: 10px; }
.pillar > p { color: var(--ink-soft); font-size: 14px; margin-bottom: 20px; }
.pillar ul { display: grid; gap: 8px; }
.pillar ul li { font-size: 13px; color: var(--ink-soft); padding-left: 16px; position: relative; }
.pillar ul li::before { content: ""; position: absolute; left: 0; top: 9px; width: 6px; height: 6px; border-radius: 50%; background: var(--accent); }

/* 产品 */
.prod-group { margin-bottom: 40px; }
.prod-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.prod-grid.two { grid-template-columns: repeat(2, 1fr); }
.prod { background: var(--surface); border: 1px solid var(--line); border-radius: 18px; padding: 30px 28px; transition: all .3s ease; display: flex; flex-direction: column; }
.prod:hover { transform: translateY(-5px); box-shadow: var(--shadow); border-color: var(--tint-strong); }
.prod-code { font-family: var(--serif); font-size: 13px; color: var(--accent-deep); letter-spacing: 1px; }
.prod h4 { font-family: var(--serif); font-size: 18px; font-weight: 700; margin: 8px 0 10px; }
.prod p { font-size: 13.5px; color: var(--ink-soft); flex: 1; }
.prod .tags { display: flex; flex-wrap: wrap; gap: 7px; margin-top: 18px; }
.prod .tags span { font-size: 11.5px; color: var(--accent-deep); background: var(--tint); padding: 4px 11px; border-radius: 100px; }

/* DRaaS */
.draas-panel { background: var(--accent-deep); color: #fff; border-radius: 24px; padding: 56px; position: relative; overflow: hidden; }
.draas-panel::after { content: ""; position: absolute; right: -60px; top: -60px; width: 300px; height: 300px; border: 1px solid rgba(255,255,255,.14); border-radius: 50%; }
.draas-panel .kicker { font-size: 12px; letter-spacing: 4px; opacity: .75; }
.draas-panel h3 { font-family: var(--serif); font-size: 24px; font-weight: 700; margin: 12px 0 10px; }
.draas-panel > p { opacity: .86; font-size: 15px; max-width: 660px; }
.draas-values { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; margin-top: 40px; position: relative; z-index: 1; }
.dval { background: rgba(255,255,255,.07); border: 1px solid rgba(255,255,255,.12); border-radius: 14px; padding: 22px 20px; }
.dval h5 { font-size: 15px; font-weight: 500; margin-bottom: 6px; }
.dval p { font-size: 12.5px; opacity: .78; }

/* 服务矩阵 */
.svc-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.svc { background: var(--surface); border: 1px solid var(--line); border-radius: 16px; padding: 26px 22px; transition: all .3s ease; }
.svc:hover { border-color: var(--tint-strong); background: #FBFCFD; transform: translateY(-4px); }
.svc .no { font-family: var(--serif); font-size: 13px; color: var(--ink-faint); letter-spacing: 2px; }
.svc h4 { font-family: var(--serif); font-size: 17px; font-weight: 700; margin: 10px 0 6px; }
.svc p { font-size: 12.5px; color: var(--ink-soft); }

/* 行业 */
.ind-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.ind { background: var(--surface); border: 1px solid var(--line); border-radius: 18px; padding: 28px 26px; }
.ind .ico { width: 44px; height: 44px; border-radius: 12px; background: var(--tint); color: var(--accent-deep); display: grid; place-items: center; margin-bottom: 16px; }
.ind .ico svg { width: 22px; height: 22px; }
.ind h4 { font-family: var(--serif); font-size: 18px; font-weight: 700; margin-bottom: 8px; }
.ind p { font-size: 13px; color: var(--ink-soft); }
.ind ul { display: grid; gap: 6px; margin-top: 12px; }
.ind ul li { font-size: 12.5px; color: var(--ink-soft); padding-left: 14px; position: relative; }
.ind ul li::before { content: ""; position: absolute; left: 0; top: 9px; width: 5px; height: 5px; border-radius: 50%; background: var(--accent); }

/* 资质 */
.honor-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.honor { display: flex; align-items: center; gap: 12px; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 15px 18px; font-size: 13.5px; color: var(--ink-soft); }
.honor .ico { color: var(--accent-deep); flex: none; display: grid; place-items: center; }
.honor .ico svg { width: 18px; height: 18px; }
.db-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 24px; }
.db-tags span { font-size: 12.5px; color: var(--accent-deep); background: var(--tint); border-radius: 100px; padding: 6px 14px; }

/* CTA / 联系 */
.cta { background: var(--accent-deep); color: #fff; border-radius: 24px; padding: 60px 56px; display: flex; align-items: center; justify-content: space-between; gap: 40px; flex-wrap: wrap; position: relative; overflow: hidden; }
.cta::after { content: ""; position: absolute; right: -40px; bottom: -90px; width: 280px; height: 280px; border: 1px solid rgba(255,255,255,.15); border-radius: 50%; }
.cta h3 { font-family: var(--serif); font-size: 24px; font-weight: 700; line-height: 1.4; }
.cta p { opacity: .82; font-size: 15px; margin-top: 10px; max-width: 520px; }
.cta .btn { background: #fff; color: var(--accent-deep); position: relative; z-index: 1; }
.cta .btn:hover { background: var(--paper-soft); }

.contact-row { display: flex; gap: 14px; flex-wrap: wrap; margin-top: 26px; }
.contact-item { display: flex; align-items: center; gap: 12px; background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 14px 20px; font-size: 14px; color: var(--ink-soft); }
.contact-item svg { width: 18px; height: 18px; color: var(--accent-deep); flex: none; }

/* 联系表单 */
.contact-grid { display: grid; grid-template-columns: 1fr 1.1fr; gap: 48px; align-items: start; }
.contact-cards { display: grid; gap: 14px; }
.c-card { display: flex; gap: 16px; background: var(--surface); border: 1px solid var(--line); border-radius: 16px; padding: 22px 24px; }
.c-card .ico { width: 44px; height: 44px; border-radius: 12px; background: var(--tint); color: var(--accent-deep); display: grid; place-items: center; flex: none; }
.c-card .ico svg { width: 22px; height: 22px; }
.c-card h4 { font-size: 15px; font-weight: 500; }
.c-card p { font-size: 13px; color: var(--ink-soft); margin-top: 2px; }

.form { background: var(--surface); border: 1px solid var(--line); border-radius: 20px; padding: 34px; }
.form label { display: block; font-size: 13px; color: var(--ink-soft); margin-bottom: 6px; }
.form input, .form textarea {
  width: 100%; padding: 12px 14px; border: 1px solid var(--line); border-radius: 10px;
  font-family: var(--sans); font-size: 14px; color: var(--ink); background: var(--paper);
  transition: border-color .25s ease, background .25s ease; margin-bottom: 18px;
}
.form input:focus, .form textarea:focus { outline: none; border-color: var(--accent); background: #fff; }
.form textarea { resize: vertical; min-height: 110px; }
.form .btn { width: 100%; justify-content: center; }

/* Footer */
footer { border-top: 1px solid var(--line); padding: 44px 0; }
.foot { display: flex; align-items: center; justify-content: space-between; gap: 20px; flex-wrap: wrap; }
.foot .brand-name { font-size: 17px; }
.foot p { font-size: 13px; color: var(--ink-faint); }
.foot .icp { color: var(--ink-faint); font-size: 13px; }
.foot .icp:hover { color: var(--accent-deep); }
.foot-links { display: flex; gap: 24px; }
.foot-links a { font-size: 13px; color: var(--ink-faint); transition: color .25s; }
.foot-links a:hover { color: var(--accent-deep); }

/* 更多链接 */
.more-link { display: inline-flex; align-items: center; gap: 8px; font-size: 14px; color: var(--accent-deep); margin-top: 30px; transition: gap .25s ease; }
.more-link:hover { gap: 12px; }
.more-link svg { width: 16px; height: 16px; }

/* Reveal */
.reveal { opacity: 0; transform: translateY(26px); transition: opacity .8s cubic-bezier(.16,1,.3,1), transform .8s cubic-bezier(.16,1,.3,1); }
.reveal.in { opacity: 1; transform: none; }

/* ---------- Responsive ---------- */
@media (max-width: 1020px) {
  .pillars, .ind-grid, .svc-grid { grid-template-columns: 1fr 1fr; }
  .prod-grid, .prod-grid.two { grid-template-columns: 1fr 1fr; }
  .draas-values { grid-template-columns: 1fr 1fr; }
  .honor-grid { grid-template-columns: 1fr 1fr; }
  .about-lead, .about-grid, .contact-grid { grid-template-columns: 1fr; }
  .hero-stats { grid-template-columns: 1fr 1fr; gap: 22px; }
}
@media (max-width: 680px) {
  .nav-links { display: none; }
  .menu-toggle { display: block; }
  .nav.open .nav-links {
    display: flex; flex-direction: column; position: absolute; top: 72px; left: 0; right: 0;
    background: var(--paper); border-bottom: 1px solid var(--line); padding: 20px 6%; gap: 20px; align-items: flex-start;
  }
  .pillars, .prod-grid, .prod-grid.two, .svc-grid, .draas-values, .honor-grid, .ind-grid { grid-template-columns: 1fr; }
  .hero { padding: 138px 0 78px; }
  .page-banner { padding: 128px 0 56px; }
  section { padding: 60px 0; }
  .about-visual, .draas-panel { padding: 34px 26px; }
  .cta { padding: 40px 28px; }
  .about-facts { grid-template-columns: 1fr; }
  .form { padding: 26px 22px; }
}
/* ============================================================
   科技感 & AI 增强（Wave 1+2）
   ============================================================ */

/* 锚点偏移：避免固定顶栏遮挡 */
[id] { scroll-margin-top: 88px; }

/* ---------- 深色科技首屏 ---------- */
body.home .hero {
  isolation: isolate;
  background:
    radial-gradient(75% 60% at 74% 16%, rgba(126,168,206,.16) 0%, transparent 56%),
    radial-gradient(60% 50% at 12% 78%, rgba(84,116,158,.20) 0%, transparent 62%),
    radial-gradient(46% 42% at 90% 58%, rgba(64,102,142,.22) 0%, transparent 66%),
    linear-gradient(160deg, #060C15 0%, #091527 42%, #0B1B30 70%, #0E2138 100%);
  color: #fff;
}
body.home .hero-bg { display: none; }
body.home .hero-grid {
  opacity: .34;
  background-image: linear-gradient(rgba(255,255,255,.05) 1px, transparent 1px),
                    linear-gradient(90deg, rgba(255,255,255,.05) 1px, transparent 1px);
  background-size: 52px 52px;
  mask-image: radial-gradient(72% 72% at 50% 25%, #000 0%, transparent 100%);
  -webkit-mask-image: radial-gradient(72% 72% at 50% 25%, #000 0%, transparent 100%);
}
#heroParticles { position: absolute; inset: 0; z-index: 0; pointer-events: none; }
body.home .hero .container { position: relative; z-index: 1; }

body.home .hero .eyebrow { color: #9CC3E0; }
body.home .hero .eyebrow::before { background: #7FA8C9; }
body.home .hero h1 { color: #fff; }
body.home .hero h1 em { color: #A8CDE8; }
body.home .hero-tagline { color: #8FB6D6; }
body.home .hero-lead { color: rgba(255,255,255,.72); }
body.home .hero-stats { border-top-color: rgba(255,255,255,.14); }
body.home .stat .num { color: #fff; }
body.home .stat .num small { color: #9CC3E0; }
body.home .stat .lbl { color: rgba(255,255,255,.6); }
body.home .hero .btn-primary { background: #6B93B5; color: #fff; box-shadow: 0 14px 34px -14px rgba(107,147,181,.7); }
body.home .hero .btn-primary:hover { background: #7FA8C9; }
body.home .hero .btn-ghost { border-color: rgba(255,255,255,.35); color: #fff; background: rgba(255,255,255,.06); }
body.home .hero .btn-ghost:hover { border-color: #9CC3E0; color: #9CC3E0; }

/* 深色首屏下的导航（未滚动时白字，滚动后切回浅色） */
body.home .nav:not(.scrolled) { background: transparent; border-bottom-color: transparent; }
body.home .nav:not(.scrolled) .brand-name { color: #fff; }
body.home .nav:not(.scrolled) .brand-sub { color: rgba(255,255,255,.55); }
body.home .nav:not(.scrolled) .brand-mark { background: rgba(255,255,255,.14); }
body.home .nav:not(.scrolled) .nav-links a { color: rgba(255,255,255,.82); }
body.home .nav:not(.scrolled) .nav-links a.active { color: #fff; }
body.home .nav:not(.scrolled) .nav-links a::after { background: #9CC3E0; }
body.home .nav:not(.scrolled) .nav-cta { border-color: rgba(255,255,255,.5); color: #fff; }
body.home .nav:not(.scrolled) .nav-cta:hover { background: rgba(255,255,255,.9); color: var(--accent-deep); }
body.home .nav:not(.scrolled) .menu-toggle { color: #fff; }

/* ---------- AI 专区 ---------- */
.ai-section {
  background:
    radial-gradient(50% 60% at 85% 10%, rgba(90,122,150,.25) 0%, transparent 60%),
    linear-gradient(135deg, #0C1626 0%, #0F1F35 55%, #12263c 100%);
  color: #fff; padding: 96px 0;
}
.ai-head { max-width: 720px; margin-bottom: 48px; }
.ai-head .eyebrow { color: #9CC3E0; }
.ai-head .eyebrow::before { background: #7FA8C9; }
.ai-head h2 { font-family: var(--serif); font-size: clamp(24px, 3.2vw, 36px); font-weight: 700; margin: 16px 0 14px; letter-spacing: 0; }
.ai-head p { color: rgba(255,255,255,.72); font-size: 15.5px; }

.ai-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; margin-bottom: 40px; }
.ai-card {
  background: rgba(255,255,255,.06); border: 1px solid rgba(255,255,255,.12); border-radius: 16px;
  padding: 26px 24px; transition: transform .3s ease, background .3s ease, border-color .3s ease;
}
.ai-card:hover { transform: translateY(-5px); background: rgba(255,255,255,.1); border-color: rgba(159,195,224,.4); }
.ai-ico { width: 44px; height: 44px; border-radius: 12px; background: rgba(159,195,224,.14); color: #A8CDE8; display: grid; place-items: center; margin-bottom: 16px; }
.ai-ico svg { width: 22px; height: 22px; }
.ai-card h4 { font-size: 16px; font-weight: 500; margin-bottom: 8px; }
.ai-card p { font-size: 13px; color: rgba(255,255,255,.68); }

/* AI 对话 Demo */
.ai-demo { max-width: 660px; background: rgba(255,255,255,.05); border: 1px solid rgba(255,255,255,.14); border-radius: 18px; overflow: hidden; }
.ai-demo-head { display: flex; align-items: center; gap: 8px; padding: 14px 18px; border-bottom: 1px solid rgba(255,255,255,.12); font-size: 13.5px; color: rgba(255,255,255,.85); }
.ai-demo-head .dot { width: 8px; height: 8px; border-radius: 50%; background: #7FC8A9; box-shadow: 0 0 8px #7FC8A9; }
.ai-chat { padding: 18px; display: grid; gap: 12px; max-height: 260px; overflow-y: auto; }
.ai-chat .msg { max-width: 85%; padding: 10px 14px; border-radius: 12px; font-size: 13px; line-height: 1.6; white-space: pre-wrap; }
.ai-chat .msg.user { justify-self: end; background: #6B93B5; color: #fff; border-bottom-right-radius: 4px; }
.ai-chat .msg.bot { justify-self: start; background: rgba(255,255,255,.1); color: rgba(255,255,255,.92); border-bottom-left-radius: 4px; }
.ai-chat .msg.bot.typing { color: rgba(255,255,255,.55); }
.ai-suggest { display: flex; flex-wrap: wrap; gap: 8px; padding: 12px 18px 18px; }
.ai-suggest button {
  font-family: var(--sans); font-size: 12.5px; color: #CFE3F2; background: transparent;
  border: 1px solid rgba(159,195,224,.35); border-radius: 100px; padding: 7px 14px; cursor: pointer;
  transition: all .2s ease;
}
.ai-suggest button:hover { background: rgba(159,195,224,.15); border-color: #9CC3E0; }

/* ---------- 返回顶部 ---------- */
#backTop {
  position: fixed; right: 24px; bottom: 24px; z-index: 70;
  width: 44px; height: 44px; border-radius: 12px; border: 1px solid var(--line);
  background: var(--surface); color: var(--accent-deep); box-shadow: var(--shadow);
  display: grid; place-items: center; cursor: pointer; opacity: 0; visibility: hidden;
  transform: translateY(12px); transition: all .3s ease;
}
#backTop.show { opacity: 1; visibility: visible; transform: none; }
#backTop:hover { background: var(--accent-deep); color: #fff; }
#backTop svg { width: 20px; height: 20px; }

/* ---------- 响应式 ---------- */
@media (max-width: 1020px) {
  .ai-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 680px) {
  .ai-grid { grid-template-columns: 1fr; }
  .ai-section { padding: 64px 0; }
}
/* 服务能力扩展：统计条 + 生命周期网格 */
.stat-strip { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; margin-bottom: 28px; }
.lifecycle-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
@media (max-width: 1020px) { .stat-strip, .lifecycle-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 680px) { .stat-strip, .lifecycle-grid { grid-template-columns: 1fr; } }