/* =====================================================
   捷通科技 · U位资产管理专题页
   深色科技主题 / 自适应 / 纯原生 CSS
   ===================================================== */
:root{
  --bg:#05080f;
  --bg2:#0a0f1e;
  --bg3:#0d1526;
  --card:rgba(148,197,255,.06);
  --line:rgba(96,165,250,.18);
  --cyan:#22d3ee;
  --blue:#3b82f6;
  --violet:#818cf8;
  --txt:#e6f0ff;
  --txt2:#94a9c9;
  --grad:linear-gradient(100deg,#22d3ee,#3b82f6 55%,#818cf8);
  --radius:16px;
  --shadow:0 20px 60px rgba(2,8,23,.6);
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:"PingFang SC","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;
  background:var(--bg);color:var(--txt);
  line-height:1.75;overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
button{font-family:inherit}
.container{width:min(1180px,92%);margin:0 auto}
.container-narrow{width:min(860px,92%);margin:0 auto}
::selection{background:rgba(34,211,238,.35)}

/* ---------- 滚动进度条 ---------- */
.scroll-progress{position:fixed;top:0;left:0;height:3px;width:0;z-index:1001;
  background:var(--grad);box-shadow:0 0 12px rgba(34,211,238,.8)}

/* ---------- 导航 ---------- */
.nav{position:fixed;top:0;left:0;right:0;z-index:1000;transition:.35s;
  padding:14px 0;background:transparent}
.nav.scrolled{background:rgba(5,8,15,.85);backdrop-filter:blur(14px);
  border-bottom:1px solid var(--line);padding:8px 0}
.nav-inner{width:min(1280px,94%);margin:0 auto;display:flex;align-items:center;justify-content:space-between}
.logo{display:flex;align-items:center;gap:10px}
.logo-mark{display:grid;place-items:center;width:42px;height:42px;border-radius:10px;
  font-weight:800;font-size:17px;color:#03121c;background:var(--grad);
  box-shadow:0 0 18px rgba(34,211,238,.45)}
.logo-text{font-weight:700;font-size:18px;letter-spacing:1px;display:flex;flex-direction:column;line-height:1.15}
.logo-text small{font-size:10px;color:var(--txt2);letter-spacing:2px;font-weight:400}
.nav-links{display:flex;align-items:center;gap:26px}
.nav-links a{font-size:14px;color:var(--txt2);position:relative;padding:6px 0;transition:.25s}
.nav-links a:not(.nav-cta):hover{color:var(--txt)}
.nav-links a:not(.nav-cta)::after{content:"";position:absolute;left:0;bottom:0;height:2px;width:0;
  background:var(--grad);transition:.3s;border-radius:2px}
.nav-links a:not(.nav-cta):hover::after{width:100%}
.nav-cta{color:#03121c!important;background:var(--grad);padding:9px 20px;border-radius:99px;
  font-weight:600;box-shadow:0 4px 20px rgba(34,211,238,.35)}
.nav-cta:hover{transform:translateY(-2px);box-shadow:0 8px 26px rgba(34,211,238,.5)}
.nav-toggle{display:none;background:none;border:0;cursor:pointer;flex-direction:column;gap:5px;padding:6px}
.nav-toggle span{display:block;width:24px;height:2px;background:var(--txt);border-radius:2px;transition:.3s}
.nav-toggle.open span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.nav-toggle.open span:nth-child(2){opacity:0}
.nav-toggle.open span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}

/* ---------- Hero ---------- */
.hero{position:relative;min-height:100vh;display:flex;align-items:center;overflow:hidden;
  background:#03060c}
.hero::before{content:"";position:absolute;inset:0;
  background:url("../../img/hero-datacenter.jpg") center/cover no-repeat;
  opacity:.35;transform:scale(1.05);animation:heroZoom 18s ease-out forwards}
@keyframes heroZoom{to{transform:scale(1)}}
.hero::after{content:"";position:absolute;inset:0;
  background:radial-gradient(ellipse at 70% 20%,rgba(59,130,246,.22),transparent 55%),
             linear-gradient(180deg,rgba(3,6,12,.55) 0%,rgba(3,6,12,.82) 70%,var(--bg) 100%)}
#particles{position:absolute;inset:0;z-index:1}
.hero-grid{position:absolute;inset:0;z-index:0;opacity:.5;
  background-image:linear-gradient(rgba(59,130,246,.08) 1px,transparent 1px),
                   linear-gradient(90deg,rgba(59,130,246,.08) 1px,transparent 1px);
  background-size:56px 56px;
  mask-image:radial-gradient(ellipse at center,black 30%,transparent 75%);
  -webkit-mask-image:radial-gradient(ellipse at center,black 30%,transparent 75%);
  animation:gridMove 24s linear infinite}
@keyframes gridMove{to{background-position:56px 56px}}
.hero-glow{position:absolute;width:640px;height:640px;border-radius:50%;z-index:0;
  background:radial-gradient(circle,rgba(34,211,238,.16),transparent 65%);
  top:-180px;right:-120px;filter:blur(10px);animation:glowFloat 9s ease-in-out infinite alternate}
@keyframes glowFloat{to{transform:translate(-60px,60px) scale(1.12)}}
.hero-inner{position:relative;z-index:2;padding:150px 0 110px}
.hero-tag{display:inline-flex;align-items:center;gap:8px;font-size:13px;letter-spacing:3px;
  color:var(--cyan);border:1px solid rgba(34,211,238,.4);padding:7px 18px;border-radius:99px;
  background:rgba(34,211,238,.07);margin-bottom:26px}
.hero-title{font-size:clamp(32px,5.4vw,62px);font-weight:800;line-height:1.22;letter-spacing:1px}
.hero-title em{font-style:normal;background:var(--grad);-webkit-background-clip:text;
  background-clip:text;color:transparent;padding-right:6px}
.type-wrap{position:relative;display:inline-block}
.type-wrap::after{content:"";display:inline-block;width:3px;height:.95em;margin-left:6px;
  background:var(--cyan);vertical-align:-.12em;animation:caret 1s steps(2) infinite}
@keyframes caret{50%{opacity:0}}
.hero-sub{max-width:640px;margin:26px 0 34px;color:var(--txt2);font-size:16.5px}
.hero-actions{display:flex;gap:16px;flex-wrap:wrap}

/* 按钮 */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:14px 34px;border-radius:99px;font-size:15px;font-weight:600;cursor:pointer;
  border:0;transition:.3s;letter-spacing:.5px}
.btn-glow{color:#03121c;background:var(--grad);position:relative;overflow:hidden;
  box-shadow:0 6px 26px rgba(34,211,238,.4)}
.btn-glow::before{content:"";position:absolute;top:0;left:-80%;width:60%;height:100%;
  background:linear-gradient(100deg,transparent,rgba(255,255,255,.55),transparent);
  transform:skewX(-20deg);animation:sheen 3.2s ease-in-out infinite}
@keyframes sheen{0%,60%{left:-80%}100%{left:130%}}
.btn-glow:hover{transform:translateY(-3px) scale(1.02);box-shadow:0 12px 34px rgba(34,211,238,.55)}
.btn-ghost{color:var(--txt);border:1px solid rgba(148,197,255,.4);background:rgba(148,197,255,.06)}
.btn-ghost:hover{border-color:var(--cyan);color:var(--cyan);transform:translateY(-3px)}
.btn-block{width:100%}

/* hero 数据 */
.hero-stats{display:grid;grid-template-columns:repeat(4,1fr);gap:18px;margin-top:64px;
  max-width:860px}
.stat{border-left:2px solid var(--cyan);padding:4px 0 4px 18px;transition:.3s}
.stat:hover{transform:translateX(6px)}
.stat b{display:block;font-size:clamp(26px,3vw,40px);font-weight:800;
  background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.stat span{font-size:12.5px;color:var(--txt2)}
.hero-scroll{position:absolute;bottom:26px;left:50%;transform:translateX(-50%);z-index:2;
  width:26px;height:44px;border:2px solid rgba(148,197,255,.4);border-radius:14px}
.hero-scroll i{position:absolute;left:50%;top:8px;width:4px;height:9px;margin-left:-2px;
  border-radius:4px;background:var(--cyan);animation:scrollHint 1.8s ease-in-out infinite}
@keyframes scrollHint{0%{transform:translateY(0);opacity:1}70%{transform:translateY(16px);opacity:0}100%{opacity:0}}

/* ---------- 通用 Section ---------- */
.sec{padding:100px 0;position:relative}
.sec-alt{background:linear-gradient(180deg,var(--bg) 0%,var(--bg2) 18%,var(--bg2) 82%,var(--bg) 100%)}
.sec-head{text-align:center;max-width:760px;margin:0 auto 58px}
.sec-eyebrow{display:inline-block;font-size:12px;letter-spacing:5px;color:var(--cyan);
  border:1px solid rgba(34,211,238,.35);padding:5px 16px;border-radius:99px;margin-bottom:16px;
  background:rgba(34,211,238,.06)}
.sec-head h2{font-size:clamp(26px,3.4vw,40px);font-weight:800;line-height:1.3}
.grad{background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.sec-head p{color:var(--txt2);margin-top:14px;font-size:15.5px}
.grid-4{display:grid;grid-template-columns:repeat(4,1fr);gap:22px}

/* 卡片通用 */
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  padding:30px 26px;transition:.35s;position:relative;overflow:hidden;backdrop-filter:blur(6px)}
.card::before{content:"";position:absolute;inset:0;border-radius:var(--radius);padding:1px;
  background:linear-gradient(130deg,rgba(34,211,238,.5),transparent 40%,transparent 60%,rgba(129,140,248,.5));
  -webkit-mask:linear-gradient(#000 0 0) content-box,linear-gradient(#000 0 0);
  -webkit-mask-composite:xor;mask-composite:exclude;opacity:0;transition:.35s;pointer-events:none}
.card:hover::before{opacity:1}
.card:hover{transform:translateY(-8px);box-shadow:var(--shadow);background:rgba(148,197,255,.09)}
.card-icon{font-size:34px;margin-bottom:16px;display:inline-grid;place-items:center;
  width:64px;height:64px;border-radius:16px;background:rgba(34,211,238,.1);
  border:1px solid rgba(34,211,238,.25)}
.card h3{font-size:18px;margin-bottom:10px}
.card p{font-size:14px;color:var(--txt2)}

/* ---------- 双引擎 ---------- */
.engine-wrap{display:grid;grid-template-columns:1fr auto 1fr;gap:28px;align-items:stretch}
.engine-card{background:var(--card);border:1px solid var(--line);border-radius:20px;
  padding:38px 34px;position:relative;overflow:hidden;transition:.4s}
.engine-card::after{content:"";position:absolute;top:-70px;right:-70px;width:220px;height:220px;
  border-radius:50%;background:radial-gradient(circle,rgba(34,211,238,.18),transparent 70%)}
.engine-badge{display:inline-block;padding:6px 18px;border-radius:99px;font-size:13px;font-weight:700;
  letter-spacing:2px;color:#03121c;background:var(--grad);margin-bottom:18px}
.badge-2{background:linear-gradient(100deg,#a78bfa,#22d3ee)}
.engine-card h3{font-size:23px;margin-bottom:14px}
.engine-desc{font-size:14.5px;color:var(--txt2);margin-bottom:24px}
.spec-list{list-style:none;display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-bottom:22px}
.spec-list li{background:rgba(10,18,34,.7);border:1px solid var(--line);border-radius:12px;
  padding:14px 16px;transition:.3s}
.spec-list li:hover{border-color:var(--cyan);transform:translateY(-3px)}
.spec-list b{display:block;font-size:22px;font-weight:800;color:var(--cyan)}
.spec-list span{font-size:12px;color:var(--txt2)}
.engine-note{font-size:13px;color:var(--txt2);border-top:1px dashed var(--line);padding-top:16px}
.engine-divider{display:flex;align-items:center}
.engine-divider span{writing-mode:vertical-lr;letter-spacing:6px;font-size:13px;color:var(--cyan);
  border:1px dashed rgba(34,211,238,.5);padding:16px 8px;border-radius:99px;
  background:rgba(34,211,238,.05);animation:pulseBorder 2.6s ease-in-out infinite}
@keyframes pulseBorder{50%{box-shadow:0 0 18px rgba(34,211,238,.45)}}

/* ---------- 架构 SVG ---------- */
.arch-svg svg{width:100%;height:auto}
.arch-layer{fill:rgba(148,197,255,.05);stroke:var(--line)}
.arch-layer.l1{stroke:rgba(34,211,238,.35)}
.arch-layer.l2{stroke:rgba(129,140,248,.35)}
.arch-layer.l3{stroke:rgba(59,130,246,.35)}
.arch-t1{fill:#e6f0ff;font-size:19px;font-weight:700}
.arch-t2{fill:#7d93b5;font-size:12px}
.node rect{fill:rgba(10,18,34,.85);stroke:rgba(34,211,238,.35);stroke-width:1;transition:.3s}
.node:hover rect{stroke:var(--cyan);filter:drop-shadow(0 0 8px rgba(34,211,238,.6))}
.node text{text-anchor:middle}
.nt1{fill:#e6f0ff;font-size:15px;font-weight:600}
.nt2{fill:#7d93b5;font-size:11px}
.proto{fill:#22d3ee;font-size:12px;text-anchor:middle;letter-spacing:1px;opacity:.9}
.flow{stroke:url(#lg1);stroke-width:1.6;fill:none;stroke-dasharray:7 6;
  animation:flowDash 1.4s linear infinite;opacity:.85}
@keyframes flowDash{to{stroke-dashoffset:-13}}

/* ---------- 可视化演示 ---------- */
.demo-wrap{display:grid;grid-template-columns:380px 1fr;gap:36px;align-items:start}
.demo-cabinet{position:relative;background:linear-gradient(180deg,#0b1220,#070b14);
  border:1px solid var(--line);border-radius:18px;padding:20px;box-shadow:var(--shadow)}
.cabinet-frame{background:#04070d;border:1px solid rgba(96,165,250,.25);border-radius:12px;padding:14px 12px;position:relative}
.cabinet-top{font-size:12px;letter-spacing:2px;color:var(--cyan);text-align:center;
  padding-bottom:10px;border-bottom:1px dashed var(--line);margin-bottom:10px}
.cabinet-base{height:26px;margin-top:10px;border-radius:6px;
  background:linear-gradient(180deg,#101a2c,#060a12);border:1px solid var(--line)}
.u-list{display:flex;flex-direction:column-reverse;gap:3px}
.u-cell{height:19px;border-radius:4px;display:flex;align-items:center;justify-content:space-between;
  padding:0 9px;font-size:10px;letter-spacing:.5px;cursor:pointer;
  border:1px solid rgba(96,165,250,.16);background:rgba(96,165,250,.05);
  color:#5f7ba3;transition:.18s;position:relative}
.u-cell.used{background:linear-gradient(90deg,rgba(59,130,246,.34),rgba(34,211,238,.2));
  border-color:rgba(59,130,246,.5);color:#dceaff}
.u-cell.free{background:rgba(96,165,250,.03)}
.u-cell.alarm{background:linear-gradient(90deg,rgba(239,68,68,.4),rgba(239,68,68,.12));
  border-color:rgba(239,68,68,.6);color:#fecaca;animation:alarmBlink 1.6s ease-in-out infinite}
@keyframes alarmBlink{50%{box-shadow:0 0 12px rgba(239,68,68,.55)}}
.u-cell.res{background:repeating-linear-gradient(45deg,rgba(129,140,248,.14) 0 6px,transparent 6px 12px);
  border-color:rgba(129,140,248,.4);color:#aab4ff}
.u-cell:hover{transform:scale(1.06);z-index:3;box-shadow:0 0 14px rgba(34,211,238,.6);border-color:var(--cyan)}
.u-cell.scanning{background:rgba(34,211,238,.55)!important;border-color:var(--cyan)!important;
  color:#03121c!important;font-weight:700}
.scanline{position:absolute;left:20px;right:20px;top:20px;height:2px;border-radius:2px;
  background:linear-gradient(90deg,transparent,var(--cyan),transparent);
  box-shadow:0 0 16px rgba(34,211,238,.9);opacity:0;pointer-events:none}
.scanline.active{animation:scanMove 3.6s linear forwards;opacity:1}
@keyframes scanMove{0%{top:8%;opacity:1}90%{opacity:1}100%{top:92%;opacity:0}}

.demo-panel{background:var(--card);border:1px solid var(--line);border-radius:18px;padding:26px}
.panel-metrics{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-bottom:22px}
.pm{background:rgba(10,18,34,.75);border:1px solid var(--line);border-radius:12px;
  padding:14px 8px;text-align:center;transition:.3s}
.pm:hover{border-color:var(--cyan);transform:translateY(-3px)}
.pm b{display:block;font-size:24px;font-weight:800;color:var(--cyan)}
.pm span{font-size:11px;color:var(--txt2)}
.u-detail{background:rgba(10,18,34,.75);border:1px solid var(--line);border-radius:14px;
  padding:20px;min-height:212px;margin-bottom:18px}
.u-detail-empty{display:flex;flex-direction:column;align-items:center;justify-content:center;
  gap:12px;height:172px;color:var(--txt2);font-size:13.5px;text-align:center;line-height:1.9}
.pulse-dot{width:12px;height:12px;border-radius:50%;background:var(--cyan);
  box-shadow:0 0 0 0 rgba(34,211,238,.6);animation:pulseDot 1.8s infinite}
@keyframes pulseDot{70%{box-shadow:0 0 0 14px rgba(34,211,238,0)}100%{box-shadow:0 0 0 0 rgba(34,211,238,0)}}
.u-badge{display:inline-block;font-size:11px;font-weight:700;letter-spacing:1px;color:#03121c;
  background:var(--grad);padding:3px 12px;border-radius:99px;margin-bottom:10px}
.u-detail h4{font-size:17px;margin-bottom:12px}
.u-detail ul{list-style:none}
.u-detail li{display:flex;justify-content:space-between;font-size:13px;padding:7px 0;
  border-bottom:1px dashed rgba(96,165,250,.14)}
.u-detail li span{color:var(--txt2)}
.u-detail li b{font-weight:600}
.u-detail li b.ok{color:#34d399}
.u-detail li b.warn{color:#f87171}
.legend{display:flex;flex-wrap:wrap;gap:14px;font-size:12px;color:var(--txt2);margin-bottom:18px}
.lg{display:inline-block;width:11px;height:11px;border-radius:3px;margin-right:6px;vertical-align:-1px}
.lg-used{background:linear-gradient(90deg,#3b82f6,#22d3ee)}
.lg-free{background:rgba(96,165,250,.1);border:1px solid rgba(96,165,250,.35)}
.lg-alarm{background:rgba(239,68,68,.55)}
.lg-res{background:repeating-linear-gradient(45deg,rgba(129,140,248,.4) 0 4px,transparent 4px 8px)}
.scan-log{margin-top:14px;font-size:12px;color:#6ee7b7;min-height:20px;font-family:Consolas,monospace}

/* ---------- 产品矩阵 ---------- */
.prod-card{padding:0;display:flex;flex-direction:column}
.prod-img{overflow:hidden;border-radius:var(--radius) var(--radius) 0 0;aspect-ratio:4/3;position:relative}
.prod-img img{width:100%;height:100%;object-fit:cover;transition:.6s}
.prod-card:hover .prod-img img{transform:scale(1.08)}
.prod-tag{position:absolute;top:14px;left:14px;z-index:2;font-size:11px;letter-spacing:2px;
  color:#03121c;background:var(--grad);padding:4px 12px;border-radius:99px;font-weight:700}
.prod-card .prod-img{position:relative}
.prod-card h3{font-size:16.5px;padding:20px 22px 8px}
.prod-card p{padding:0 22px 24px;flex:1}

/* ---------- 参数表 ---------- */
.table-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:16px;
  background:var(--card);-webkit-overflow-scrolling:touch}
.spec-table{width:100%;border-collapse:collapse;min-width:640px;font-size:14px}
.spec-table th{background:rgba(34,211,238,.1);color:var(--cyan);font-weight:700;
  padding:15px 20px;text-align:left;letter-spacing:1px;white-space:nowrap}
.spec-table td{padding:13px 20px;border-top:1px solid rgba(96,165,250,.12);color:var(--txt2)}
.spec-table td:first-child{color:var(--txt);font-weight:600;white-space:nowrap}
.spec-table tr{transition:.25s}
.spec-table tbody tr:hover{background:rgba(34,211,238,.05)}

/* ---------- 场景 tabs ---------- */
.tabs{background:var(--card);border:1px solid var(--line);border-radius:20px;overflow:hidden}
.tab-btns{display:flex;border-bottom:1px solid var(--line);flex-wrap:wrap}
.tab-btn{flex:1;min-width:120px;padding:16px 10px;background:none;border:0;color:var(--txt2);
  font-size:14.5px;cursor:pointer;position:relative;transition:.3s;letter-spacing:1px}
.tab-btn::after{content:"";position:absolute;left:25%;right:25%;bottom:0;height:3px;
  border-radius:3px;background:var(--grad);transform:scaleX(0);transition:.3s}
.tab-btn.active{color:var(--txt);background:rgba(34,211,238,.05)}
.tab-btn.active::after{transform:scaleX(1)}
.tab-btn:hover{color:var(--cyan)}
.tab-panel{display:none;padding:36px;animation:fadeUp .5s ease}
.tab-panel.active{display:block}
@keyframes fadeUp{from{opacity:0;transform:translateY(16px)}to{opacity:1;transform:none}}
.scene-body{display:grid;grid-template-columns:1fr 1.15fr;gap:34px;align-items:center}
.scene-img img{border-radius:14px;border:1px solid var(--line);box-shadow:var(--shadow)}
.scene-text h3{font-size:21px;margin-bottom:14px}
.scene-text p{font-size:14.5px;color:var(--txt2);margin-bottom:18px}
.check-list{list-style:none}
.check-list li{font-size:14px;padding:7px 0 7px 30px;position:relative;color:var(--txt)}
.check-list li::before{content:"✓";position:absolute;left:0;top:6px;width:20px;height:20px;
  border-radius:50%;display:grid;place-items:center;font-size:11px;color:#03121c;
  background:var(--grad);font-weight:800}

/* ---------- 步骤 ---------- */
.steps{display:grid;grid-template-columns:repeat(5,1fr);gap:16px;counter-reset:step}
.step{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:26px 20px;
  position:relative;transition:.35s;overflow:hidden}
.step::before{content:"";position:absolute;left:0;top:0;bottom:0;width:3px;
  background:var(--grad);transform:scaleY(0);transform-origin:top;transition:.4s}
.step:hover{transform:translateY(-8px);box-shadow:var(--shadow)}
.step:hover::before{transform:scaleY(1)}
.step i{font-style:normal;font-size:30px;font-weight:800;
  background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent;
  display:block;margin-bottom:10px}
.step h4{font-size:15.5px;margin-bottom:8px}
.step p{font-size:12.5px;color:var(--txt2);margin-bottom:12px}
.step-t{display:inline-block;font-size:11px;color:var(--cyan);border:1px solid rgba(34,211,238,.4);
  padding:2px 10px;border-radius:99px}
.benefit-row{margin-top:34px;grid-template-columns:repeat(4,1fr)}
.benefit{background:rgba(34,211,238,.05);border:1px solid rgba(34,211,238,.25);border-radius:16px;
  padding:24px 18px;text-align:center;transition:.3s}
.benefit:hover{transform:translateY(-6px);box-shadow:0 0 30px rgba(34,211,238,.18)}
.benefit b{font-size:38px;font-weight:800;background:var(--grad);
  -webkit-background-clip:text;background-clip:text;color:transparent}
.benefit em{display:block;font-style:normal;font-size:13px;color:var(--txt);margin:2px 0 6px}
.benefit span{font-size:12px;color:var(--txt2)}

/* ---------- FAQ ---------- */
.faq-list{display:flex;flex-direction:column;gap:14px}
.faq-item{background:var(--card);border:1px solid var(--line);border-radius:14px;
  padding:0 24px;transition:.3s}
.faq-item[open]{border-color:rgba(34,211,238,.5);box-shadow:0 0 26px rgba(34,211,238,.12)}
.faq-item summary{padding:19px 0;font-size:15.5px;font-weight:600;cursor:pointer;
  list-style:none;display:flex;justify-content:space-between;align-items:center;gap:16px}
.faq-item summary::-webkit-details-marker{display:none}
.faq-item summary i{flex:none;width:22px;height:22px;border-radius:50%;position:relative;
  background:rgba(34,211,238,.15);border:1px solid rgba(34,211,238,.4);transition:.3s}
.faq-item summary i::before,.faq-item summary i::after{content:"";position:absolute;
  background:var(--cyan);top:50%;left:50%;transform:translate(-50%,-50%)}
.faq-item summary i::before{width:10px;height:2px}
.faq-item summary i::after{width:2px;height:10px;transition:.3s}
.faq-item[open] summary i::after{transform:translate(-50%,-50%) rotate(90deg);opacity:0}
.faq-item p{padding:0 0 20px;color:var(--txt2);font-size:14px}

/* ---------- CTA ---------- */
.sec-cta{background:
  radial-gradient(ellipse at 20% 30%,rgba(59,130,246,.15),transparent 55%),
  radial-gradient(ellipse at 85% 70%,rgba(34,211,238,.12),transparent 55%),var(--bg2)}
.cta-wrap{display:grid;grid-template-columns:1.1fr 1fr;gap:48px;align-items:center}
.cta-text h2{font-size:clamp(24px,3vw,34px);margin-bottom:16px}
.cta-text p{color:var(--txt2);font-size:15px;margin-bottom:26px}
.cta-info{display:grid;gap:12px}
.cta-info div{display:flex;gap:14px;align-items:baseline;font-size:14px}
.cta-info b{color:var(--cyan);font-size:12px;letter-spacing:2px;flex:none;width:44px}
.cta-form{background:var(--card);border:1px solid var(--line);border-radius:20px;padding:32px;
  backdrop-filter:blur(10px);box-shadow:var(--shadow)}
.f-row{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.f-field{margin-bottom:16px}
.f-field label{display:block;font-size:12.5px;color:var(--txt2);margin-bottom:7px;letter-spacing:1px}
.f-field input,.f-field textarea{width:100%;background:rgba(4,8,16,.7);border:1px solid var(--line);
  border-radius:10px;padding:13px 15px;color:var(--txt);font-size:14px;font-family:inherit;
  transition:.3s;resize:vertical}
.f-field input:focus,.f-field textarea:focus{outline:none;border-color:var(--cyan);
  box-shadow:0 0 0 3px rgba(34,211,238,.15)}
.f-tip{font-size:11.5px;color:var(--txt2);text-align:center;margin-top:12px;transition:.3s;line-height:1.7}
.f-tip.err{color:#f87171}
.f-tip.ok{color:#34d399}
.f-tip.warn{color:#fbbf24}
.f-field label i{font-style:normal;color:#f87171;margin-left:2px}
.cta-form input:focus,.cta-form textarea:focus{outline:none}
.btn:disabled{opacity:.6;cursor:not-allowed;transform:none!important}
input.err-field,textarea.err-field{border-color:#f87171!important;box-shadow:0 0 0 3px rgba(248,113,113,.15)!important}

/* ---------- 页脚 ---------- */
.footer{border-top:1px solid var(--line);background:#04070d;padding:64px 0 0}
.footer-inner{display:grid;grid-template-columns:1.6fr 1fr 1fr 1.1fr;gap:36px;padding-bottom:44px}
.f-col p{font-size:13px;color:var(--txt2);margin-top:14px}
.f-col h5{font-size:14px;margin-bottom:16px;letter-spacing:2px;color:var(--txt)}
.f-col a,.f-col span{display:block;font-size:13px;color:var(--txt2);padding:4px 0;transition:.25s}
.f-col a:hover{color:var(--cyan);transform:translateX(4px)}
.footer-bar{border-top:1px solid rgba(96,165,250,.1);text-align:center;padding:18px;
  font-size:12px;color:#5f7ba3}

/* ---------- 返回顶部 ---------- */
.backtop{position:fixed;right:26px;bottom:26px;width:46px;height:46px;border-radius:50%;
  border:1px solid rgba(34,211,238,.5);background:rgba(10,18,34,.85);color:var(--cyan);
  font-size:18px;cursor:pointer;opacity:0;pointer-events:none;transition:.35s;z-index:999;
  backdrop-filter:blur(6px)}
.backtop.show{opacity:1;pointer-events:auto}
.backtop:hover{background:var(--grad);color:#03121c;box-shadow:0 0 22px rgba(34,211,238,.5)}

/* ---------- 滚动显现 ---------- */
.reveal{opacity:0;transform:translateY(34px);transition:opacity .8s ease,transform .8s ease}
.reveal.in{opacity:1;transform:none}
.reveal:nth-child(2){transition-delay:.1s}
.card.reveal.in:nth-child(2){transition-delay:.1s}
.grid-4>.reveal.in:nth-child(1){transition-delay:0s}
.grid-4>.reveal.in:nth-child(2){transition-delay:.12s}
.grid-4>.reveal.in:nth-child(3){transition-delay:.24s}
.grid-4>.reveal.in:nth-child(4){transition-delay:.36s}

/* ---------- 3D 倾斜 ---------- */
.tilt{transform-style:preserve-3d;will-change:transform}
.tilt.tilting{transition:transform .08s linear}

/* =====================================================
   响应式
   ===================================================== */
@media (max-width:1024px){
  .grid-4{grid-template-columns:repeat(2,1fr)}
  .engine-wrap{grid-template-columns:1fr}
  .engine-divider{justify-content:center}
  .engine-divider span{writing-mode:horizontal-tb;padding:8px 20px}
  .demo-wrap{grid-template-columns:1fr}
  .demo-cabinet{max-width:420px;margin:0 auto;width:100%}
  .scene-body{grid-template-columns:1fr}
  .steps{grid-template-columns:repeat(3,1fr)}
  .benefit-row{grid-template-columns:repeat(2,1fr)}
  .cta-wrap{grid-template-columns:1fr;gap:34px}
  .footer-inner{grid-template-columns:repeat(2,1fr)}
}
@media (max-width:768px){
  .nav-links{position:fixed;top:0;right:-100%;width:min(320px,80vw);height:100vh;
    background:rgba(5,8,15,.97);backdrop-filter:blur(16px);flex-direction:column;
    justify-content:center;gap:8px;transition:right .4s ease;border-left:1px solid var(--line)}
  .nav-links.open{right:0}
  .nav-links a{font-size:16px;padding:12px 0;width:100%;text-align:center}
  .nav-toggle{display:flex;z-index:1002;position:relative}
  .sec{padding:70px 0}
  .hero-inner{padding:130px 0 90px}
  .hero-stats{grid-template-columns:repeat(2,1fr);gap:14px;margin-top:44px}
  .panel-metrics{grid-template-columns:repeat(2,1fr)}
  .steps{grid-template-columns:repeat(2,1fr)}
  .spec-list{grid-template-columns:1fr 1fr}
  .tab-panel{padding:24px 18px}
  .f-row{grid-template-columns:1fr}
  .arch-svg{overflow-x:auto}
  .arch-svg svg{min-width:720px}
}
@media (max-width:520px){
  .grid-4{grid-template-columns:1fr}
  .steps{grid-template-columns:1fr}
  .benefit-row{grid-template-columns:1fr}
  .footer-inner{grid-template-columns:1fr}
  .hero-title{font-size:30px}
  .spec-list{grid-template-columns:1fr}
  .hero-actions .btn{width:100%}
  .u-cell{height:22px}
}