:root{
  --paper:#F4F2EC;
  --paper-2:#EAE7DD;
  --ink:#15140F;
  --ink-soft:#454339;
  --muted:#6E6A5C;
  --accent:#D24B2E;
  --line:#15140F;
  --maxw:1180px;
  --sans:"Helvetica Neue","Arial","PingFang SC","Microsoft YaHei","Segoe UI",sans-serif;
  --mono:"Courier New","Consolas",monospace;
}
*{box-sizing:border-box;margin:0;padding:0;}
html{scroll-behavior:smooth;}
body{font-family:var(--sans);color:var(--ink);background:var(--paper);line-height:1.8;-webkit-font-smoothing:antialiased;}
img{display:block;max-width:100%;height:auto;}
a{color:inherit;text-decoration:none;}
.container{width:100%;max-width:var(--maxw);margin:0 auto;padding:0 32px;}

/* Header */
.site-header{position:sticky;top:0;z-index:50;background:var(--paper);border-bottom:1.5px solid var(--ink);}
.nav{display:flex;align-items:center;justify-content:space-between;height:72px;}
.brand img{height:38px;width:auto;}
.nav-links{display:flex;gap:30px;font-size:14px;font-weight:600;letter-spacing:.01em;color:var(--ink-soft);}
.nav-links a{padding:4px 0;border-bottom:2px solid transparent;transition:border-color .15s,color .15s;}
.nav-links a:hover{color:var(--accent);border-color:var(--accent);}

/* Hero */
.hero{padding:72px 0 0;border-bottom:1.5px solid var(--ink);}
.hero-grid{display:grid;grid-template-columns:1fr 1fr;gap:56px;align-items:center;padding-bottom:64px;}
.eyebrow{display:block;font-size:13px;font-weight:700;letter-spacing:.18em;text-transform:uppercase;color:var(--accent);margin-bottom:26px;}
h1{font-size:clamp(34px,5vw,60px);line-height:1.04;font-weight:800;letter-spacing:-.03em;margin-bottom:26px;}
.lede{font-size:19px;color:var(--ink-soft);max-width:32em;margin-bottom:32px;}
.cta-row{display:flex;gap:0;flex-wrap:wrap;}
.btn{display:inline-block;font-size:15px;font-weight:700;letter-spacing:.01em;padding:14px 30px;border:1.5px solid var(--ink);transition:background .15s,color .15s;}
.btn-primary{background:var(--ink);color:var(--paper);}
.btn-primary:hover{background:var(--accent);border-color:var(--accent);}
.btn-line{background:transparent;color:var(--ink);border-left:none;}
.btn-line:hover{background:var(--ink);color:var(--paper);}
.btn-api{background:var(--accent);color:var(--paper);border-color:var(--accent);}
.btn-api:hover{background:var(--ink);border-color:var(--ink);}
.hero-art img{width:100%;border:1.5px solid var(--ink);}

/* Section + 网格行 */
.section{padding:74px 0;border-bottom:1.5px solid var(--ink);}
.section-alt{background:var(--paper-2);}
.section-dark{background:var(--ink);color:var(--paper);}
.row{display:grid;grid-template-columns:200px 1fr;gap:48px;align-items:start;}
.row-label{display:flex;flex-direction:column;gap:6px;font-size:13px;font-weight:700;letter-spacing:.16em;text-transform:uppercase;color:var(--muted);padding-top:8px;border-top:3px solid var(--ink);}
.section-dark .row-label{color:#9C9888;border-top-color:var(--accent);}
.num{font-family:var(--mono);font-size:34px;font-weight:700;color:var(--accent);letter-spacing:0;line-height:1;}
.row-body{max-width:760px;}

h2{font-size:clamp(26px,3.4vw,40px);font-weight:800;letter-spacing:-.02em;line-height:1.1;margin-bottom:22px;}
h3{font-size:clamp(18px,2vw,23px);font-weight:700;letter-spacing:-.01em;margin:28px 0 8px;}
h4{font-size:15px;font-weight:700;letter-spacing:.04em;text-transform:uppercase;color:var(--accent);margin:18px 0 6px;}
.section p{color:var(--ink-soft);font-size:17px;margin-bottom:14px;}
.section-dark p{color:#C9C5B8;}
.section-dark h3{color:var(--paper);}

/* 插图 */
.full-art{margin:26px 0;}
.full-art img{width:100%;max-width:520px;border:1.5px solid var(--ink);}
.section-dark .full-art img{border-color:#3A3730;}

/* 能力网格：硬线分隔 */
.grid-2{display:grid;grid-template-columns:1fr 1fr;border-top:1.5px solid var(--ink);border-left:1.5px solid var(--ink);margin-top:18px;}
.cell{padding:26px 28px;border-right:1.5px solid var(--ink);border-bottom:1.5px solid var(--ink);}
.cell h3{margin-top:0;}
.cell h3::before{content:"→ ";color:var(--accent);}
.cell p{margin:0;font-size:15.5px;}

/* Footer */
.site-footer{background:var(--ink);color:#A8A496;padding:56px 0 28px;}
.footer-grid{display:flex;justify-content:space-between;gap:40px;flex-wrap:wrap;padding-bottom:30px;border-bottom:1px solid #34322B;}
.footer-brand img{height:36px;margin-bottom:14px;filter:invert(1) brightness(1.7) grayscale(1);}
.footer-brand p{max-width:30em;font-size:15px;}
.footer-links{display:flex;flex-direction:column;gap:10px;font-size:14px;font-weight:600;}
.footer-links a:hover{color:var(--accent);}
.footer-bottom{padding-top:18px;font-size:13px;color:#73705F;letter-spacing:.02em;}

/* Responsive */
@media (max-width:860px){
  .nav-links{display:none;}
  .hero-grid{grid-template-columns:1fr;gap:32px;padding-bottom:48px;}
  .row{grid-template-columns:1fr;gap:18px;}
  .row-label{flex-direction:row;align-items:baseline;gap:12px;}
  .grid-2{grid-template-columns:1fr;}
  .section{padding:48px 0;}
  .hero{padding:48px 0 0;}
}