/* ============================================================
   南方數據 — B2B Data Centre & Network
   Design tokens + global styles
   ============================================================ */

:root{
  --bg:        #05080f;
  --bg-elev:   #0a1018;
  --bg-card:   #0d1520;
  --ink:       #eaf0f9;
  --ink-dim:   #a8b4c6;
  --muted:     #6f7d92;
  --line:      rgba(255,255,255,.09);
  --line-soft: rgba(255,255,255,.05);
  --accent:    #2e7dff;
  --accent-ink:#8fb6ff;
  --cyan:      #45e0ff;
  --ok:        #35d07f;

  --maxw: 1240px;
  --gut: 32px;
  --r: 2px;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC",
               "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", Roboto, sans-serif;
  --font-mono: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
}

*,*::before,*::after{ box-sizing:border-box; }

html{ -webkit-text-size-adjust:100%; scroll-behavior:smooth; }
@media (prefers-reduced-motion: reduce){ html{ scroll-behavior:auto; } }

body{
  margin:0;
  background:var(--bg);
  color:var(--ink);
  font-family:var(--font-sans);
  font-size:16px;
  line-height:1.65;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
  overflow-x:hidden;
}

img{ max-width:100%; display:block; }
a{ color:inherit; text-decoration:none; }
button{ font:inherit; color:inherit; }

/* ---------- layout ---------- */
.wrap{
  width:100%;
  max-width:var(--maxw);
  margin-inline:auto;
  padding-inline:var(--gut);
}
.section{ padding-block:120px; border-top:1px solid var(--line-soft); }
.section--tight{ padding-block:80px; }
.section--plain{ border-top:0; }

/* ---------- typography ---------- */
h1,h2,h3,h4{ margin:0; font-weight:600; letter-spacing:-.02em; line-height:1.08; }
h1{ font-size:clamp(34px, 4.6vw, 62px); letter-spacing:-.035em; line-height:1.12; }
h2{ font-size:clamp(28px, 3.4vw, 46px); letter-spacing:-.03em; }
h3{ font-size:clamp(19px, 1.7vw, 23px); line-height:1.3; letter-spacing:-.015em; }
h4{ font-size:17px; line-height:1.4; }
p{ margin:0; }

.lede{
  font-size:clamp(16px,1.35vw,19px);
  line-height:1.7;
  color:var(--ink-dim);
  max-width:62ch;
}
.small{ font-size:14px; color:var(--muted); line-height:1.6; }

.eyebrow{
  display:flex; align-items:center; gap:10px;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--accent-ink);
  margin-bottom:22px;
}
.eyebrow::before{
  content:""; width:22px; height:1px; background:var(--accent);
  display:block; flex:none;
}

.hl{ color:var(--accent-ink); }

/* ---------- header ---------- */
.hdr{
  position:sticky; top:0; z-index:100;
  border-bottom:1px solid transparent;
  transition:background .35s ease, border-color .35s ease, backdrop-filter .35s;
}
.hdr.is-stuck{
  background:rgba(5,8,15,.86);
  backdrop-filter:saturate(140%) blur(14px);
  border-bottom-color:var(--line);
}
.hdr__in{
  display:flex; align-items:center; gap:40px;
  height:74px;
}
.brand{ display:flex; align-items:center; gap:11px; flex:none; }
.brand__mark{ width:26px; height:26px; flex:none; }
.brand__name{
  font-size:15px; font-weight:600; letter-spacing:.14em; text-transform:uppercase;
}
.brand__sub{
  font-family:var(--font-mono); font-size:10px; letter-spacing:.18em;
  color:var(--muted); text-transform:uppercase; margin-top:2px; line-height:1;
}

.nav{ display:flex; gap:30px; margin-left:auto; }
.nav a{
  font-size:14px; color:var(--ink-dim);
  padding-block:6px; position:relative; transition:color .2s;
}
.nav a::after{
  content:""; position:absolute; left:0; right:100%; bottom:0; height:1px;
  background:var(--accent); transition:right .28s ease;
}
.nav a:hover{ color:var(--ink); }
.nav a:hover::after,
.nav a[aria-current="page"]::after{ right:0; }
.nav a[aria-current="page"]{ color:var(--ink); }

.hdr__cta{ display:flex; align-items:center; gap:14px; flex:none; }

.burger{
  display:none; width:44px; height:44px; margin-left:auto;
  background:none; border:1px solid var(--line); border-radius:var(--r);
  align-items:center; justify-content:center; cursor:pointer;
}
.burger span{ display:block; width:16px; height:1px; background:var(--ink); position:relative; }
.burger span::before,.burger span::after{
  content:""; position:absolute; left:0; width:16px; height:1px; background:var(--ink);
}
.burger span::before{ top:-5px; } .burger span::after{ top:5px; }

/* mobile drawer */
.drawer{
  position:fixed; inset:74px 0 0; z-index:99;
  background:var(--bg); border-top:1px solid var(--line);
  padding:28px var(--gut) 40px;
  display:none; flex-direction:column; gap:4px;
  overflow-y:auto;
}
.drawer.is-open{ display:flex; }
.drawer a{
  font-size:22px; letter-spacing:-.02em; padding-block:14px;
  border-bottom:1px solid var(--line-soft);
}
.drawer .btn{ margin-top:22px; justify-content:center; }

/* ---------- buttons ---------- */
.btn{
  display:inline-flex; align-items:center; gap:9px;
  height:46px; padding-inline:22px;
  border:1px solid var(--line);
  border-radius:var(--r);
  font-size:14px; font-weight:500;
  background:transparent; color:var(--ink);
  cursor:pointer; transition:background .2s, border-color .2s, color .2s, transform .2s;
  min-height:44px;
}
.btn:hover{ border-color:rgba(255,255,255,.28); background:rgba(255,255,255,.03); }
.btn--primary{
  background:var(--accent); border-color:var(--accent); color:#fff;
}
.btn--primary:hover{ background:#4a90ff; border-color:#4a90ff; }
.btn--ghost{ border-color:transparent; padding-inline:0; }
.btn--ghost:hover{ background:none; border-color:transparent; color:var(--accent-ink); }
.btn__arrow{ transition:transform .2s; }
.btn:hover .btn__arrow{ transform:translateX(3px); }

.link-arrow{
  display:inline-flex; align-items:center; gap:8px;
  color:var(--accent-ink); font-size:14px; font-weight:500;
}
.link-arrow svg{ transition:transform .2s; }
.link-arrow:hover svg{ transform:translateX(3px); }

/* ---------- hero ---------- */
.hero{
  position:relative;
  padding-block:110px 96px;
  overflow:hidden;
  border-bottom:1px solid var(--line-soft);
}
.hero__grid{
  display:grid; grid-template-columns:1.05fr .95fr; gap:64px; align-items:center;
}
.hero__mesh{
  position:absolute; inset:0; pointer-events:none; opacity:.5;
  background-image:
    linear-gradient(to right, var(--line-soft) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line-soft) 1px, transparent 1px);
  background-size:72px 72px;
  mask-image:radial-gradient(ellipse 80% 60% at 30% 20%, #000 20%, transparent 75%);
  -webkit-mask-image:radial-gradient(ellipse 80% 60% at 30% 20%, #000 20%, transparent 75%);
}
.hero__in{ position:relative; }
.hero h1{ margin-bottom:26px; text-wrap:balance; }
.hero .lede{ margin-bottom:36px; }
.hero__actions{ display:flex; flex-wrap:wrap; gap:14px 24px; align-items:center; }

.hero__aside{
  position:relative;
  border:1px solid var(--line);
  background:linear-gradient(160deg, rgba(46,125,255,.08), rgba(5,8,15,0) 55%), var(--bg-elev);
  padding:26px;
}
.hero__aside-hd{
  display:flex; justify-content:space-between; align-items:center;
  flex-wrap:wrap; row-gap:8px;
  font-family:var(--font-mono); font-size:11px; letter-spacing:.14em;
  text-transform:uppercase; color:var(--muted);
  padding-bottom:16px; border-bottom:1px solid var(--line-soft); margin-bottom:18px;
}
.dot-live{
  display:inline-flex; align-items:center; gap:7px; color:var(--ok);
}
.dot-live::before{
  content:""; width:6px; height:6px; border-radius:50%; background:var(--ok);
  box-shadow:0 0 0 3px rgba(53,208,127,.14);
}

/* ---------- stat strip ---------- */
.stats{
  display:grid; grid-template-columns:repeat(4,1fr);
  border-top:1px solid var(--line-soft);
}
.stat{
  padding:34px 28px 30px;
  border-right:1px solid var(--line-soft);
}
.stat:last-child{ border-right:0; }
.stat__k{
  font-family:var(--font-mono); font-size:11px; letter-spacing:.14em;
  text-transform:uppercase; color:var(--muted); margin-bottom:14px;
}
.stat__v{ font-size:clamp(26px,2.6vw,38px); font-weight:600; letter-spacing:-.03em; line-height:1; }
.stat__v span{ font-size:.5em; color:var(--muted); margin-left:4px; letter-spacing:0; }
.stat__d{ font-size:13px; color:var(--muted); margin-top:10px; }

/* ---------- generic grid/cards ---------- */
.grid-2{ display:grid; grid-template-columns:repeat(2,1fr); gap:1px; background:var(--line-soft); border:1px solid var(--line-soft); }
.grid-3{ display:grid; grid-template-columns:repeat(3,1fr); gap:1px; background:var(--line-soft); border:1px solid var(--line-soft); }

.cell{
  background:var(--bg); padding:38px 32px 42px;
  transition:background .25s;
  position:relative;
}
.cell:hover{ background:var(--bg-card); }
.cell__no{
  font-family:var(--font-mono); font-size:11px; letter-spacing:.14em;
  color:var(--muted); margin-bottom:26px; display:block;
}
.cell h3{ margin-bottom:12px; }
.cell p{ color:var(--ink-dim); font-size:14.5px; line-height:1.68; }
.cell ul{ margin:18px 0 0; padding:0; list-style:none; }
.cell li{
  font-size:13.5px; color:var(--ink-dim); padding:7px 0;
  border-top:1px solid var(--line-soft); display:flex; gap:10px;
}
.cell li::before{ content:"·"; color:var(--accent); }

/* ---------- split content ---------- */
.split{ display:grid; grid-template-columns:.9fr 1.1fr; gap:80px; align-items:start; }
.split--rev{ grid-template-columns:1.1fr .9fr; }

.spec-table{ width:100%; border-collapse:collapse; }
.spec-table th,.spec-table td{
  text-align:left; padding:15px 0; border-bottom:1px solid var(--line-soft);
  font-size:14.5px; vertical-align:top;
}
.spec-table th{ color:var(--muted); font-weight:400; width:42%; }
.spec-table td{ color:var(--ink); }

/* ---------- timeline / process ---------- */
.steps{ display:grid; grid-template-columns:repeat(4,1fr); gap:0; border-top:1px solid var(--line); }
.step{ padding:30px 26px 0 0; position:relative; }
.step::before{
  content:""; position:absolute; top:-4px; left:0; width:7px; height:7px;
  background:var(--accent); border-radius:50%;
}
.step__n{ font-family:var(--font-mono); font-size:11px; letter-spacing:.14em; color:var(--accent-ink); }
.step h4{ margin:10px 0 8px; }
.step p{ font-size:13.5px; color:var(--muted); line-height:1.6; }

/* ---------- facility cards ---------- */
.fac{
  display:grid; grid-template-columns:1.15fr 1fr; gap:1px;
  background:var(--line-soft); border:1px solid var(--line-soft);
}
.fac__media{
  background:
    radial-gradient(circle at 70% 30%, rgba(46,125,255,.18), transparent 60%),
    var(--bg-elev);
  padding:34px; min-height:300px; display:flex; flex-direction:column; justify-content:space-between;
  position:relative; overflow:hidden;
}
.fac__body{ background:var(--bg); padding:38px 36px; }
.fac__tag{
  display:inline-flex; align-items:center; gap:8px;
  font-family:var(--font-mono); font-size:11px; letter-spacing:.12em; text-transform:uppercase;
  color:var(--ok); border:1px solid rgba(53,208,127,.3); padding:4px 10px;
  background:rgba(53,208,127,.06);
}
.fac__specs{ display:grid; grid-template-columns:repeat(2,1fr); gap:18px 24px; margin-top:26px; }
.fac__specs div span{ display:block; font-family:var(--font-mono); font-size:10.5px; letter-spacing:.1em; text-transform:uppercase; color:var(--muted); margin-bottom:3px; }
.fac__specs div strong{ font-weight:500; font-size:14.5px; }

/* ---------- network diagram ---------- */
.topology{ width:100%; height:auto; }
.topo-node{ fill:var(--bg-card); stroke:var(--line); }
.topo-line{ stroke:rgba(46,125,255,.45); stroke-width:1; fill:none; }
.topo-line--dash{ stroke-dasharray:3 4; stroke:rgba(255,255,255,.16); }
.topo-txt{ fill:var(--ink-dim); font-family:var(--font-mono); font-size:9px; letter-spacing:.06em; }
.topo-txt--accent{ fill:var(--accent-ink); }

/* ---------- CTA band ---------- */
.cta{
  border-top:1px solid var(--line);
  background:
    radial-gradient(ellipse 60% 100% at 80% 0%, rgba(46,125,255,.14), transparent 70%),
    var(--bg-elev);
  padding-block:88px;
}
.cta__in{ display:flex; justify-content:space-between; align-items:end; gap:48px; flex-wrap:wrap; }
.cta h2{ max-width:26ch; text-wrap:balance; }

/* ---------- footer ---------- */
.ftr{ border-top:1px solid var(--line); padding-block:64px 40px; font-size:14px; }
.ftr__top{ display:grid; grid-template-columns:1.4fr repeat(3,1fr); gap:48px; padding-bottom:56px; }
.ftr__brand p{ color:var(--muted); margin-top:18px; max-width:34ch; font-size:13.5px; }
.ftr h5{
  font-family:var(--font-mono); font-size:11px; letter-spacing:.14em; text-transform:uppercase;
  color:var(--muted); margin:0 0 18px; font-weight:400;
}
.ftr ul{ list-style:none; margin:0; padding:0; display:grid; gap:11px; }
.ftr ul a{ color:var(--ink-dim); font-size:14px; transition:color .2s; }
.ftr ul a:hover{ color:var(--ink); }
.ftr__bot{
  display:flex; justify-content:space-between; gap:24px; flex-wrap:wrap;
  padding-top:26px; border-top:1px solid var(--line-soft);
  font-size:12.5px; color:var(--muted);
}
.ftr__bot a{ color:var(--muted); }
.ftr__bot a:hover{ color:var(--ink); }

/* ---------- forms ---------- */
.form{ display:grid; gap:20px; }
.field{ display:grid; gap:8px; }
.field label{
  font-family:var(--font-mono); font-size:11px; letter-spacing:.12em;
  text-transform:uppercase; color:var(--muted);
}
.field input,.field textarea,.field select{
  background:var(--bg-elev); border:1px solid var(--line); border-radius:var(--r);
  padding:13px 14px; color:var(--ink); font-size:15px; font-family:inherit;
  transition:border-color .2s, background .2s;
}
.field input:focus,.field textarea:focus,.field select:focus{
  outline:none; border-color:var(--accent); background:#0b1421;
}
.field textarea{ resize:vertical; min-height:120px; }
.form__row{ display:grid; grid-template-columns:1fr 1fr; gap:20px; }

/* ---------- misc ---------- */
.tag{
  display:inline-block; font-family:var(--font-mono); font-size:10.5px;
  letter-spacing:.12em; text-transform:uppercase; color:var(--muted);
  border:1px solid var(--line); padding:4px 9px;
}
.rule{ height:1px; background:var(--line-soft); border:0; margin:0; }
.note{
  border:1px solid var(--line); padding:20px 22px; font-size:13.5px;
  color:var(--ink-dim); background:var(--bg-elev);
}
.note strong{ color:var(--ink); }

/* reveal on scroll —— 默认可见，JS 就绪后才启用动画（避免无 JS 时内容不可见） */
.reveal{ opacity:1; transform:none; }
.js-ready .reveal{ opacity:0; transform:translateY(14px); transition:opacity .7s ease, transform .7s ease; }
.js-ready .reveal.is-in{ opacity:1; transform:none; }
@media (prefers-reduced-motion: reduce){
  .js-ready .reveal{ opacity:1; transform:none; transition:none; }
}

/* page header */
.pagehead{ padding-block:96px 72px; border-bottom:1px solid var(--line-soft); position:relative; overflow:hidden; }
.pagehead .lede{ margin-top:22px; }
.crumb{
  font-family:var(--font-mono); font-size:11px; letter-spacing:.12em;
  text-transform:uppercase; color:var(--muted); margin-bottom:26px;
}
.crumb a:hover{ color:var(--ink); }

/* ---------- responsive ---------- */
@media (max-width:1080px){
  .nav{ display:none; }
  .hdr__cta{ display:none; }
  .burger{ display:flex; }
  .hero__grid{ grid-template-columns:1fr; gap:48px; }
  .split,.split--rev{ grid-template-columns:1fr; gap:44px; }
  .stats{ grid-template-columns:repeat(2,1fr); }
  .stat{ border-bottom:1px solid var(--line-soft); }
  .stat:nth-child(2n){ border-right:0; }
  .grid-3{ grid-template-columns:1fr; }
  .fac{ grid-template-columns:1fr; }
  .ftr__top{ grid-template-columns:1fr 1fr; gap:40px; }
  .steps{ grid-template-columns:repeat(2,1fr); gap:0 24px; }
}
@media (max-width:720px){
  :root{ --gut:20px; }
  .section{ padding-block:76px; }
  .section--tight{ padding-block:56px; }
  .hero{ padding-block:64px 64px; }
  .pagehead{ padding-block:56px 48px; }
  .grid-2{ grid-template-columns:1fr; }
  .stats{ grid-template-columns:1fr; }
  .stat{ border-right:0; }
  .form__row{ grid-template-columns:1fr; }
  .fac__body,.cell,.hero__aside{ padding:26px 22px; }
  .ftr__top{ grid-template-columns:1fr; gap:34px; }
  .steps{ grid-template-columns:1fr; gap:26px; }
  .cta__in{ flex-direction:column; align-items:flex-start; }
  .btn{ width:100%; justify-content:center; }
  .btn--ghost{ width:auto; }
  .hero__actions .btn{ width:100%; }
}