/* ============================================================
   深度行动 · 长三角AI平台  ChangSanJiaoAI.com
   Design System — dark indigo tech aesthetic
   ============================================================ */
:root{
  --bg:#0a0d3a;
  --bg2:#0e1230;
  --card:#1f2454;
  --line:rgba(255,255,255,.08);
  --brand:#5865f2;
  --brand-soft:#8fa0ff;
  --magenta:#ec48bd;
  --magenta-soft:#f3a8e0;
  --green:#35ed7e;
  --green-soft:#7fe9ae;
  --cyan:#00b0f4;
  --cyan-soft:#6fd3ff;
  --amber:#f59e0b;
  --text:#ffffff;
  --muted:#c9ccee;
  --faint:#8b8fc4;
  --radius:20px;
  --radius-sm:16px;
  --font:"Noto Sans SC","PingFang SC","Microsoft YaHei","Source Han Sans SC","Helvetica Neue",Arial,sans-serif;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:var(--font);
  background:var(--bg);
  color:var(--text);
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
.container{max-width:1200px;margin:0 auto;padding:0 24px}

/* ---------- Header ---------- */
.site-header{
  position:sticky;top:0;z-index:100;
  background:rgba(10,13,58,.82);
  backdrop-filter:blur(14px);
  -webkit-backdrop-filter:blur(14px);
  border-bottom:1px solid var(--line);
}
.header-inner{
  display:flex;align-items:center;justify-content:space-between;
  gap:24px;padding:14px 0;
}
.logo{display:flex;align-items:center;gap:18px;flex-shrink:0}
.logo-mark{width:96px;height:96px;flex-shrink:0}
.logo-text{display:flex;flex-direction:column;gap:4px;line-height:1.05}
.logo-action{font-size:18px;font-weight:500;color:#a6a9d6;letter-spacing:.5px;line-height:1.1}
.logo-action .reg{font-size:.55em;font-weight:400;margin-left:1px;vertical-align:super;color:#a6a9d6}
.logo-main{font-size:32px;font-weight:900;letter-spacing:.5px;line-height:1.05;color:#fff}
.logo-url{font-size:21px;font-weight:700;letter-spacing:.5px;line-height:1;white-space:nowrap}
.logo-url .url-csj{color:var(--cyan)}
.logo-url .url-ai{color:var(--green)}

.main-nav{display:flex;align-items:center;gap:28px}
.main-nav a{
  font-size:15px;font-weight:500;color:#c9ccee;
  padding:6px 2px;position:relative;transition:color .25s;
}
.main-nav a:hover{color:#fff}
.main-nav a.active{color:#fff}
.main-nav a.active::after{
  content:"";position:absolute;left:0;right:0;bottom:-2px;height:2px;
  border-radius:2px;background:linear-gradient(90deg,var(--brand),var(--magenta));
}
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:11px 22px;border-radius:10px;font-size:15px;font-weight:700;
  cursor:pointer;border:1px solid transparent;transition:transform .2s,box-shadow .2s,background .25s;
  white-space:nowrap;
}
.btn:hover{transform:translateY(-2px)}
.btn-primary{background:var(--green);color:#0a0d3a}
.btn-primary:hover{box-shadow:0 8px 24px rgba(53,237,126,.35)}
.btn-blue{background:var(--brand);color:#fff}
.btn-blue:hover{box-shadow:0 8px 24px rgba(88,101,242,.45)}
.btn-ghost{background:rgba(19,22,51,.9);border-color:rgba(255,255,255,.14);color:#fff}
.btn-ghost:hover{border-color:rgba(255,255,255,.35)}
.btn-white{background:#fff;color:#0a0d3a}
.btn-outline-w{background:transparent;border-color:rgba(255,255,255,.45);color:#fff}

.nav-toggle{display:none;background:none;border:0;cursor:pointer;padding:8px}
.nav-toggle span{display:block;width:22px;height:2px;background:#fff;margin:5px 0;border-radius:2px;transition:.3s}

/* ---------- Logo mark: 长 glyph rendered as circuit-board traces (static, no animation) ---------- */

/* ---------- Hero (index) ---------- */
.hero{
  background:linear-gradient(180deg,#0a0d3a 0%,#141849 100%);
  padding:96px 0 104px;
}
.hero-inner{display:grid;grid-template-columns:1.35fr 1fr;gap:56px;align-items:center}
.hero-badge{
  display:inline-flex;align-items:center;gap:8px;
  padding:8px 16px;border-radius:9999px;
  background:rgba(255,255,255,.08);
  border:1px solid rgba(236,72,189,.4);
  color:var(--magenta-soft);font-size:13px;font-weight:500;margin-bottom:26px;
}
.hero h1{font-size:56px;font-weight:900;letter-spacing:-1px;line-height:1.18;margin-bottom:22px}
.hero h1 .grad{
  background:linear-gradient(90deg,var(--brand-soft),var(--magenta));
  -webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;
}
.hero-sub{font-size:19px;color:var(--muted);line-height:1.7;margin-bottom:34px;max-width:560px}
.hero-ctas{display:flex;gap:16px;margin-bottom:30px}
.hero-trust{font-size:14px;color:var(--faint)}
.hero-visual{position:relative}
.hero-visual img{
  width:100%;border-radius:24px;
  box-shadow:0 24px 80px rgba(88,101,242,.35),0 4px 24px rgba(0,0,0,.4);
}

/* ---------- Sections ---------- */
.section{padding:88px 0}
.section.bg2{background:var(--bg2)}
.section-head{margin-bottom:44px;max-width:760px}
.eyebrow{font-size:13px;font-weight:700;letter-spacing:1.5px;text-transform:uppercase;margin-bottom:12px}
.eyebrow.cyan{color:var(--cyan)}
.eyebrow.pink{color:var(--magenta)}
.eyebrow.green{color:var(--green)}
.eyebrow.blue{color:var(--brand-soft)}
.eyebrow.amber{color:var(--amber)}
.section-title{font-size:36px;font-weight:900;line-height:1.25;margin-bottom:12px}
.section-sub{font-size:17px;color:var(--muted)}

/* ---------- Page hero (subpages) ---------- */
.page-hero{
  background:linear-gradient(180deg,#0a0d3a 0%,#141849 100%);
  padding:64px 0 60px;
}
.page-hero .eyebrow{margin-bottom:14px}
.page-hero h1{font-size:40px;font-weight:900;margin-bottom:14px}
.page-hero p{font-size:17px;color:var(--muted);max-width:820px}

/* ---------- Grids ---------- */
.grid{display:grid;gap:24px}
.grid-4{grid-template-columns:repeat(4,1fr)}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-2{grid-template-columns:repeat(2,1fr)}

/* ---------- Region cards ---------- */
.region-card{
  background:var(--card);border-radius:var(--radius);padding:28px;
  border:1px solid transparent;transition:transform .3s,border-color .3s,box-shadow .3s;
}
.region-card:hover{transform:translateY(-6px);box-shadow:0 16px 48px rgba(0,0,0,.35)}
.region-card.b-blue{border-color:rgba(88,101,242,.28)}
.region-card.b-green{border-color:rgba(53,237,126,.28)}
.region-card.b-cyan{border-color:rgba(0,176,244,.28)}
.region-card.b-pink{border-color:rgba(236,72,189,.28)}
.region-head{display:flex;align-items:center;gap:10px;margin-bottom:14px}
.region-head .dot{width:12px;height:12px;border-radius:50%;flex-shrink:0}
.region-head h3{font-size:20px;font-weight:900;flex:1}
.region-head .tag{font-size:12px;font-weight:600}
.region-pos{font-size:13px;font-weight:600;margin-bottom:12px}
.region-caps{font-size:14px;color:var(--muted);line-height:1.8;margin-bottom:16px}
.region-metric{font-size:18px;font-weight:900}
.c-blue{color:var(--brand)}.c-green{color:var(--green)}.c-cyan{color:var(--cyan)}.c-pink{color:var(--magenta)}.c-amber{color:var(--amber)}
.t-blue{color:var(--brand-soft)}.t-green{color:var(--green-soft)}.t-cyan{color:var(--cyan-soft)}.t-pink{color:var(--magenta-soft)}

/* ---------- Capability cards ---------- */
.cap-card{
  background:var(--card);border:1px solid var(--line);border-radius:var(--radius-sm);
  padding:26px;transition:transform .3s,border-color .3s;
}
.cap-card:hover{transform:translateY(-6px);border-color:rgba(255,255,255,.18)}
.cap-icon{
  width:48px;height:48px;border-radius:12px;display:flex;align-items:center;justify-content:center;
  margin-bottom:14px;
}
.cap-icon.i-blue{background:rgba(88,101,242,.15)}
.cap-icon.i-pink{background:rgba(236,72,189,.15)}
.cap-icon.i-cyan{background:rgba(0,176,244,.15)}
.cap-icon.i-green{background:rgba(53,237,126,.15)}
.cap-icon.i-amber{background:rgba(245,158,11,.15)}
.cap-card h3{font-size:18px;font-weight:700;margin-bottom:10px}
.cap-card p{font-size:14px;color:var(--muted);line-height:1.65;margin-bottom:14px}
.cap-link{font-size:13px;font-weight:600;color:var(--brand-soft);transition:color .25s}
.cap-link:hover{color:#fff}

/* ---------- Stats band ---------- */
.stats-band{
  background:linear-gradient(90deg,#5865f2 0%,#8c45ca 50%,#ec48bd 100%);
  padding:72px 0;
}
.stats-band .eyebrow{color:#e6e8ff}
.stats-row{display:flex;justify-content:space-between;gap:24px;margin-top:40px;flex-wrap:wrap}
.stat{text-align:center;flex:1;min-width:140px}
.stat .num{font-size:52px;font-weight:900;line-height:1.1}
.stat .label{font-size:15px;color:#e6e8ff;margin-top:8px}

/* ---------- Steps ---------- */
.step-card{background:var(--card);border-radius:var(--radius-sm);padding:28px}
.step-num{font-size:32px;font-weight:900;margin-bottom:12px}
.step-card h3{font-size:18px;font-weight:700;margin-bottom:10px}
.step-card p{font-size:14px;color:var(--muted);line-height:1.65}

/* ---------- News ---------- */
.news-item{
  display:flex;gap:24px;align-items:flex-start;
  background:var(--card);border:1px solid var(--line);border-radius:var(--radius-sm);
  padding:24px;transition:transform .3s,border-color .3s;
}
.news-item:hover{transform:translateY(-4px);border-color:rgba(255,255,255,.18)}
.news-meta{width:150px;flex-shrink:0;font-size:12px;font-weight:600;line-height:1.7}
.news-body h3{font-size:17px;font-weight:700;margin-bottom:6px}
.news-body p{font-size:14px;color:var(--muted);line-height:1.65}
.news-more{margin-top:28px;text-align:right}
.news-more a{font-size:15px;font-weight:600;color:var(--brand-soft)}
.news-more a:hover{color:#fff}

/* ---------- Coop cards / chips ---------- */
.coop-card{background:var(--card);border-radius:var(--radius-sm);padding:28px;border:1px solid transparent}
.coop-card.b-green{border-color:rgba(53,237,126,.25)}
.coop-card.b-blue{border-color:rgba(88,101,242,.25)}
.coop-card.b-pink{border-color:rgba(236,72,189,.25)}
.coop-card h3{font-size:19px;font-weight:900;margin-bottom:10px}
.coop-card p{font-size:14px;color:var(--muted);line-height:1.75}
.chip-row{display:flex;flex-wrap:wrap;gap:12px}
.chip{
  padding:10px 18px;border-radius:9999px;font-size:14px;color:var(--muted);
  background:rgba(255,255,255,.06);border:1px solid rgba(255,255,255,.12);
  transition:.25s;
}
.chip:hover{color:#fff;border-color:rgba(255,255,255,.35)}

/* ---------- Values / Contact ---------- */
.value-card{background:var(--card);border:1px solid rgba(255,255,255,.08);border-radius:var(--radius-sm);padding:28px}
.value-card h3{font-size:19px;font-weight:900;margin-bottom:10px}
.value-card p{font-size:14px;color:var(--muted);line-height:1.75}
.intro-text{font-size:16px;color:var(--muted);line-height:1.9;max-width:960px}

/* ---------- Final CTA ---------- */
.final-cta{
  background:linear-gradient(90deg,#5865f2 0%,#ec48bd 100%);
  padding:80px 0;text-align:center;
}
.final-cta h2{font-size:40px;font-weight:900;margin-bottom:14px}
.final-cta p{font-size:18px;color:#e6e8ff;margin-bottom:32px}
.cta-buttons{display:flex;gap:16px;justify-content:center;flex-wrap:wrap}

/* ---------- Footer ---------- */
.site-footer{background:var(--bg);padding:64px 0 32px}
.footer-top{display:flex;justify-content:space-between;gap:48px;align-items:flex-start;flex-wrap:wrap;margin-bottom:48px}
.footer-brand{max-width:340px;display:flex;flex-direction:column;gap:16px}
.footer-brand .logo-mark{width:84px;height:84px}
.footer-brand .logo-action{font-size:16px}
.footer-brand .logo-main{font-size:26px}
.footer-brand .logo-url{font-size:17px;letter-spacing:.5px}
.footer-brand p{font-size:14px;color:var(--faint);line-height:1.7}
.footer-links{display:flex;gap:80px;flex-wrap:wrap}
.footer-col{display:flex;flex-direction:column;gap:14px;min-width:120px}
.footer-col h4{font-size:15px;font-weight:700;margin-bottom:4px}
.footer-col a{font-size:14px;color:#9aa0ce;transition:color .25s}
.footer-col a:hover{color:#fff}
.footer-divider{height:1px;background:rgba(255,255,255,.1);margin-bottom:24px}
.footer-bottom{display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;gap:6px}
.footer-bottom p{font-size:13px;color:var(--faint)}
.footer-bottom a{font-size:13px;color:#a6a9d6;font-weight:500}
.footer-bottom a:hover{color:#fff}

/* ---------- Reveal animation ---------- */
.reveal{opacity:0;transform:translateY(26px);transition:opacity .7s ease,transform .7s ease}
.reveal.in{opacity:1;transform:none}

/* ---------- Responsive ---------- */
@media (max-width:1100px){
  .hero h1{font-size:44px}
  .grid-4{grid-template-columns:repeat(2,1fr)}
  .grid-3{grid-template-columns:repeat(2,1fr)}
  .footer-links{gap:48px}
}
@media (max-width:900px){
  .main-nav{
    position:fixed;top:70px;right:0;width:min(320px,80vw);
    flex-direction:column;align-items:flex-start;gap:8px;
    background:#141849;border:1px solid var(--line);border-radius:16px;
    padding:20px;margin:0 16px;
    transform:translateX(120%);transition:transform .35s ease;
  }
  .main-nav.open{transform:translateX(0)}
  .main-nav a{width:100%;padding:10px 8px}
  .nav-toggle{display:block}
  .header-cta{display:none}
  .hero{padding:64px 0 72px}
  .hero-inner{grid-template-columns:1fr;gap:40px}
  .hero h1{font-size:38px}
  .section{padding:64px 0}
  .section-title{font-size:28px}
  .page-hero h1{font-size:32px}
  .stats-row{gap:32px}
  .stat .num{font-size:40px}
}
@media (max-width:640px){
  .grid-4,.grid-3,.grid-2{grid-template-columns:1fr}
  .hero-ctas{flex-direction:column;align-items:stretch}
  .news-item{flex-direction:column;gap:10px}
  .news-meta{width:auto;display:flex;gap:10px}
  .footer-top{flex-direction:column}
  .footer-bottom{flex-direction:column;align-items:center;text-align:center}
  .logo-mark{width:72px;height:72px}
  .logo-main{font-size:24px}
  .footer-brand .logo-mark{width:64px;height:64px}
}