/* stagetrusspro.com — site.css | DESIGN.md §1 token: P-03 炭底橙焰 / Archivo+Inter */
:root{
  --bg:#1C1917; --surface:#292524; --surface2:#33302c;
  --text:#F5F5F4; --muted:#A8A29E;
  --primary:#F97316; --accent:#FBBF24; --line:#44403C;
  --radius-card:10px; --radius-btn:8px;
  --container:1200px;
  --ease:cubic-bezier(.22,.61,.36,1);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
html.js .reveal{opacity:0;transform:translateY(18px);transition:opacity .5s var(--ease),transform .5s var(--ease)}
html.js .reveal.is-visible{opacity:1;transform:none}
body{
  margin:0;background:var(--bg);color:var(--text);
  font-family:Inter,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  font-size:16px;line-height:1.7;-webkit-font-smoothing:antialiased;
}
h1,h2,h3,h4{font-family:Archivo,Inter,sans-serif;line-height:1.25;margin:0 0 .6em;letter-spacing:.01em}
h1{font-size:clamp(2rem,4.5vw,3.2rem);font-weight:700}
h2{font-size:clamp(1.5rem,3vw,2.1rem);font-weight:700}
h3{font-size:1.2rem;font-weight:600}
p{margin:0 0 1em}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%;height:auto;display:block}
.num{font-variant-numeric:tabular-nums}
.wrap{max-width:var(--container);margin:0 auto;padding:0 24px}
section.block{padding:72px 0}
.eyebrow{color:var(--primary);font-weight:600;letter-spacing:.12em;text-transform:uppercase;font-size:.8rem;margin-bottom:.6em}

/* header */
.site-header{position:sticky;top:0;z-index:50;background:rgba(28,25,23,.96);border-bottom:1px solid var(--line)}
.header-inner{display:flex;align-items:center;gap:28px;height:68px}
.brand{font-family:Archivo,sans-serif;font-weight:700;font-size:1.25rem;color:var(--text);white-space:nowrap}
.brand b{color:var(--primary)}
.main-nav{display:flex;gap:4px;margin-left:auto}
.main-nav a{color:var(--text);padding:10px 12px;font-size:.95rem;border-radius:6px;white-space:nowrap}
.main-nav a:hover{background:var(--surface);text-decoration:none}
.nav-cta{margin-left:8px}
.nav-toggle{display:none;background:none;border:1px solid var(--line);border-radius:6px;color:var(--text);padding:8px 12px;font-size:1.1rem;cursor:pointer}

/* buttons */
.btn{display:inline-block;padding:13px 28px;border-radius:var(--radius-btn);font-weight:600;font-size:1rem;cursor:pointer;border:0;transition:transform .15s var(--ease),background .2s}
.btn-primary{background:var(--primary);color:#1C1917}
.btn-primary:active{transform:scale(.97)}
.btn-ghost{background:transparent;color:var(--text);border:1px solid var(--line)}
.btn-ghost:active{transform:scale(.97)}
@media (hover: hover){
  .btn-primary:hover{background:#fb8b3c;text-decoration:none}
  .btn-ghost:hover{border-color:var(--primary);text-decoration:none}
  .card:hover{border-color:var(--primary)}
  .case-card:hover{border-color:var(--primary)}
}

/* hero */
.hero{position:relative;overflow:hidden;background:#141210}
.hero-bg{position:absolute;inset:0}
.hero-bg img{width:100%;height:100%;object-fit:cover;opacity:.42}
.hero-inner{position:relative;padding:110px 0 90px;max-width:760px}
.hero p.lead{font-size:1.15rem;color:#e7e5e4;max-width:640px}
.hero-ctas{display:flex;gap:14px;margin-top:28px;flex-wrap:wrap}

/* grids & cards */
.grid{display:grid;gap:20px;min-width:0}
.grid>*{min-width:0}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-4{grid-template-columns:repeat(4,1fr)}
.grid-5{grid-template-columns:repeat(5,1fr)}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-card);padding:24px;transition:border-color .2s}
.card h3{margin-top:0}
.card img{border-radius:6px;margin-bottom:14px}

/* proof: case cards */
.case-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-card);overflow:hidden;transition:border-color .2s}
.case-card img{width:100%;height:220px;object-fit:cover}
.case-card .case-body{padding:22px}
.case-tag{display:inline-block;font-size:.78rem;font-weight:600;color:var(--accent);border:1px solid var(--line);border-radius:20px;padding:3px 12px;margin-bottom:10px}

/* two-col layout */
.cols{display:grid;grid-template-columns:minmax(0,2fr) minmax(0,1fr);gap:36px;align-items:start}
.cols>*{min-width:0}
.side-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-card);padding:26px;position:sticky;top:92px}
.side-card h3{margin-top:0;color:var(--accent)}

/* spec table */
.spec-table{width:100%;border-collapse:collapse;font-size:.95rem;margin:18px 0}
.spec-table th,.spec-table td{text-align:left;padding:10px 14px;border-bottom:1px solid var(--line);vertical-align:top}
.spec-table th{width:38%;color:var(--muted);font-weight:600;background:rgba(255,255,255,.02)}
.table-wrap{overflow-x:auto;max-width:100%}

/* model index */
.model-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:16px}
.model-grid>*{min-width:0}
.model-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-card);padding:18px;transition:border-color .2s}
.model-card h3{font-size:1.05rem;margin:0 0 6px}
.model-card .spec{font-size:.85rem;color:var(--muted);margin-bottom:10px}
.model-card img{border-radius:6px;margin-bottom:10px;aspect-ratio:4/3;object-fit:cover;width:100%}
@media (hover: hover){.model-card:hover{border-color:var(--primary)}}

/* cta band */
.cta-band{background:linear-gradient(120deg,#2a2118,#1C1917);border-top:1px solid var(--line);border-bottom:1px solid var(--line);text-align:center;padding:64px 0}
.cta-band h2{margin-bottom:.4em}

/* stats band (proof 数据证据带：数字全部来自事实清单) */
.stats-band{background:var(--surface);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;text-align:center;padding:44px 0}
.stats-grid>*{min-width:0}
.stat-num{font-family:Archivo,sans-serif;font-size:2.4rem;font-weight:700;color:var(--accent)}
.stat-label{color:var(--muted);font-size:.92rem}

/* process */
.process-steps{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;counter-reset:step}
.process-steps>*{min-width:0}
.step{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-card);padding:22px;position:relative}
.step::before{counter-increment:step;content:counter(step);display:flex;align-items:center;justify-content:center;width:36px;height:36px;border-radius:50%;background:var(--primary);color:#1C1917;font-weight:700;margin-bottom:12px}

/* breadcrumb */
.crumb{font-size:.88rem;color:var(--muted);margin:22px 0 0}
.crumb a{color:var(--muted)}

/* article */
.prose-layout{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:44px;align-items:start}
.prose-layout>*{min-width:0}
.prose{max-width:72ch}
.prose h2{margin-top:1.8em}
.prose ul,.prose ol{padding-left:1.4em}
.prose li{margin-bottom:.5em}
.toc{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-card);padding:20px;position:sticky;top:92px;font-size:.92rem}
.toc h3{font-size:1rem;margin-top:0}
.toc ul{list-style:none;padding:0;margin:0}
.toc li{margin-bottom:8px}

/* forms */
.lead-form label{display:block;margin-bottom:14px;font-weight:500}
.lead-form input,.lead-form select,.lead-form textarea{width:100%;margin-top:6px;padding:12px 14px;border-radius:var(--radius-btn);border:1px solid var(--line);background:#141210;color:var(--text);font-size:1rem;font-family:inherit}
.lead-form input:focus,.lead-form textarea:focus,.lead-form select:focus{outline:2px solid var(--primary);border-color:var(--primary)}
.lead-form [aria-invalid="true"]{border-color:#ef4444}
.honeypot{position:absolute;left:-9999px;top:auto;width:1px;height:1px;overflow:hidden}
.form-err{color:#fca5a5;font-size:.88rem;margin-top:4px;display:none}

/* footer */
.site-footer{border-top:1px solid var(--line);background:#141210;padding:56px 0 28px;margin-top:0}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:32px}
.footer-grid>*{min-width:0}
.footer-grid h4{font-size:1rem;margin:0 0 12px;color:var(--accent)}
.footer-grid ul{list-style:none;padding:0;margin:0}
.footer-grid li{margin-bottom:8px}
.footer-grid a{color:var(--muted);font-size:.93rem}
.footer-bottom{border-top:1px solid var(--line);margin-top:36px;padding-top:20px;color:var(--muted);font-size:.85rem;display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap}

/* responsive */
@media(max-width:1023px){
  .grid-5{grid-template-columns:repeat(3,1fr)}
  .grid-4{grid-template-columns:repeat(2,1fr)}
  .process-steps{grid-template-columns:repeat(2,1fr)}
  .footer-grid{grid-template-columns:1fr 1fr}
  .prose-layout{grid-template-columns:1fr}
  .toc{position:static}
}
@media(max-width:899px){
  .main-nav{display:none;position:absolute;top:68px;left:0;right:0;background:#1C1917;flex-direction:column;padding:12px 24px 20px;border-bottom:1px solid var(--line)}
  .main-nav.open{display:flex}
  .nav-toggle{display:block;margin-left:auto}
  .nav-cta .btn{display:none}
  .header-inner{gap:12px}
  .cols{grid-template-columns:1fr}
  .side-card{position:static}
  .grid-3{grid-template-columns:1fr}
  .grid-5{grid-template-columns:1fr 1fr}
  .stats-grid{grid-template-columns:repeat(2,1fr)}
  section.block{padding:48px 0}
  .hero-inner{padding:72px 0 60px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.01ms!important;transition-duration:.01ms!important}
  html.js .reveal{opacity:1;transform:none}
}