:root{
  --ink:#142f3d;
  --ink-2:#294858;
  --text:#263238;
  --muted:#64757f;
  --line:#dfe6e8;
  --paper:#ffffff;
  --soft:#f4f6f5;
  --soft-2:#eef2f1;
  --accent:#bb6f2a;
  --accent-2:#d18a46;
  --max:1180px;
  --radius:16px;
  --shadow:0 16px 40px rgba(20,47,61,.08);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",Arial,sans-serif;
  color:var(--text);
  background:var(--paper);
  line-height:1.65;
}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
button,input,select,textarea{font:inherit}
.container{width:min(var(--max),calc(100% - 40px));margin:0 auto}
.eyebrow{color:var(--accent);font-weight:700;letter-spacing:.08em;font-size:14px}
.section{padding:84px 0}
.section.soft{background:var(--soft)}
.section-title{font-size:42px;line-height:1.18;margin:0 0 16px;color:#12191d;letter-spacing:-.02em}
.section-lead{max-width:760px;color:var(--muted);font-size:18px;margin:0 0 38px}
.grid{display:grid;gap:24px}
.grid-2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid-4{grid-template-columns:repeat(4,minmax(0,1fr))}
.card{
  background:#fff;border:1px solid var(--line);border-radius:var(--radius);
  padding:28px;transition:.22s ease;min-height:100%;
}
.card:hover{transform:translateY(-4px);box-shadow:var(--shadow);border-color:#d8c1ad}
.card h3{margin:14px 0 8px;font-size:22px;color:#111a1f}
.card p{margin:0;color:var(--muted)}
.icon{
  width:52px;height:52px;border-radius:12px;background:var(--soft-2);
  display:flex;align-items:center;justify-content:center;color:var(--ink);font-size:24px;font-weight:700;
}
.icon.accent{background:#f6ece2;color:var(--accent)}
.link{display:inline-flex;align-items:center;gap:8px;margin-top:20px;color:var(--accent);font-weight:700}
.link:after{content:"→";transition:.2s}
.link:hover:after{transform:translateX(4px)}
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  min-height:48px;padding:0 24px;border-radius:8px;border:1px solid transparent;
  cursor:pointer;font-weight:700;transition:.2s;
}
.btn.primary{background:var(--accent);color:#fff}
.btn.primary:hover{background:#a85e1e}
.btn.ghost{border-color:rgba(255,255,255,.55);color:#fff;background:rgba(255,255,255,.05)}
.btn.outline{border-color:var(--ink);color:var(--ink);background:#fff}
.btn.small{min-height:40px;padding:0 18px}
.tag{display:inline-flex;padding:5px 10px;border-radius:999px;background:var(--soft-2);font-size:13px;color:var(--ink-2)}
.tags{display:flex;gap:8px;flex-wrap:wrap}

/* Header */
.site-header{
  position:sticky;top:0;z-index:50;background:rgba(255,255,255,.96);backdrop-filter:blur(10px);
  border-bottom:1px solid rgba(20,47,61,.08);
}
.header-inner{height:78px;display:flex;align-items:center;justify-content:space-between;gap:24px}
.brand{display:flex;align-items:baseline;gap:10px;white-space:nowrap}
.brand-cn{font-size:27px;font-weight:900;color:var(--ink);letter-spacing:-.04em}
.brand-en{font-size:15px;color:#6c7d86;letter-spacing:.05em}
.nav{display:flex;align-items:center;gap:28px}
.nav a{font-size:15px;color:#425763;position:relative;padding:28px 0}
.nav a:hover,.nav a.active{color:var(--ink)}
.nav a.active:after{content:"";height:2px;background:var(--accent);position:absolute;left:0;right:0;bottom:18px}
.header-cta{white-space:nowrap}
.menu-btn{display:none;border:0;background:transparent;font-size:28px;color:var(--ink);cursor:pointer}

/* Hero */
.hero{
  min-height:650px;display:flex;align-items:center;position:relative;overflow:hidden;color:#fff;
  background:
    radial-gradient(circle at 18% 28%,rgba(88,109,151,.50),transparent 26%),
    radial-gradient(circle at 78% 27%,rgba(112,133,81,.48),transparent 24%),
    radial-gradient(circle at 72% 72%,rgba(173,124,58,.18),transparent 20%),
    linear-gradient(112deg,#0d2b3b 0%,#193c4c 48%,#273f3c 100%);
}
.hero:before,.hero:after{
  content:"";position:absolute;border-radius:50%;filter:blur(12px);opacity:.45
}
.hero:before{width:520px;height:520px;right:-90px;top:-120px;background:repeating-radial-gradient(circle,#91a55e 0 8px,#57733f 9px 18px)}
.hero:after{width:430px;height:430px;left:-120px;bottom:-170px;background:repeating-radial-gradient(circle,#879bc8 0 7px,#405c89 8px 16px)}
.hero-content{position:relative;z-index:2;max-width:850px;text-align:center;margin:0 auto;padding:70px 0}
.hero h1{font-size:56px;line-height:1.12;margin:0 0 22px;letter-spacing:-.04em}
.hero p{font-size:21px;color:rgba(255,255,255,.84);margin:0 auto 34px;max-width:820px}
.hero-actions{display:flex;gap:16px;justify-content:center;flex-wrap:wrap}
.hero-note{margin-top:30px;color:rgba(255,255,255,.64);font-size:14px}

/* Page hero */
.page-hero{background:var(--soft);padding:82px 0 72px;border-bottom:1px solid var(--line)}
.page-hero h1{font-size:46px;margin:0 0 12px;color:#111a1f}
.page-hero p{font-size:18px;color:var(--muted);max-width:780px;margin:0}

/* Value strip */
.value-strip{margin-top:-54px;position:relative;z-index:3}
.value-box{
  background:#fff;border:1px solid var(--line);border-radius:18px;box-shadow:var(--shadow);
  padding:22px;display:grid;grid-template-columns:repeat(4,1fr);gap:18px
}
.value-item{padding:10px 14px;border-right:1px solid var(--line)}
.value-item:last-child{border-right:0}
.value-item strong{display:block;color:var(--ink);font-size:17px}
.value-item span{color:var(--muted);font-size:14px}

/* Process */
.process{display:grid;grid-template-columns:repeat(5,1fr);gap:18px;counter-reset:step}
.process-item{position:relative;padding:28px 20px;border-top:2px solid var(--line)}
.process-item:before{
  counter-increment:step;content:"0" counter(step);
  font-size:13px;font-weight:800;color:var(--accent);letter-spacing:.08em;
}
.process-item h3{font-size:18px;margin:8px 0 6px}
.process-item p{margin:0;color:var(--muted);font-size:14px}

/* Filters */
.filters{display:flex;flex-wrap:wrap;gap:10px;margin-bottom:28px}
.filter-btn{
  border:1px solid var(--line);background:#fff;color:var(--ink-2);border-radius:999px;
  padding:9px 16px;cursor:pointer
}
.filter-btn.active,.filter-btn:hover{background:var(--ink);color:#fff;border-color:var(--ink)}
.product-card .meta,.article-card .meta{font-size:13px;color:var(--muted);margin-bottom:8px}
.product-card ul,.detail-panel ul{padding-left:20px;color:var(--muted);margin:14px 0 0}
.product-card li,.detail-panel li{margin:4px 0}

/* Detail */
.detail-layout{display:grid;grid-template-columns:1.45fr .7fr;gap:36px;align-items:start}
.detail-panel{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:34px}
.detail-panel h2{margin-top:0;font-size:30px;color:#111a1f}
.side-panel{position:sticky;top:105px}
.side-panel .card{margin-bottom:18px}
.kv{display:grid;grid-template-columns:140px 1fr;gap:12px;border-top:1px solid var(--line);padding:13px 0}
.kv:first-child{border-top:0}

/* About */
.quote{
  font-size:30px;line-height:1.45;color:var(--ink);font-weight:750;
  border-left:4px solid var(--accent);padding-left:24px;margin:0
}
.split{display:grid;grid-template-columns:1fr 1fr;gap:48px;align-items:center}
.visual{
  min-height:360px;border-radius:24px;
  background:
    radial-gradient(circle at 30% 30%,rgba(187,111,42,.4),transparent 20%),
    radial-gradient(circle at 72% 62%,rgba(74,112,92,.55),transparent 22%),
    linear-gradient(145deg,#183443,#e6ecea);
  position:relative;overflow:hidden;
}
.visual:before{
  content:"CHB CHEM";position:absolute;inset:auto 28px 24px auto;
  font-weight:900;color:rgba(255,255,255,.75);font-size:28px;letter-spacing:.08em
}

/* Article */
.article-list{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.article-card{border:1px solid var(--line);border-radius:var(--radius);padding:24px;background:#fff}
.article-card h3{font-size:21px;line-height:1.4;margin:8px 0 10px}
.article-card p{color:var(--muted);margin:0}
.prose{max-width:850px;margin:0 auto}
.prose h2{margin-top:40px;color:#111a1f}
.prose p,.prose li{color:#40535d}
.prose .lead{font-size:20px;color:#52656f}
.notice{background:#fff6ec;border-left:3px solid var(--accent);padding:18px 20px;border-radius:8px;color:#6b4b2f}

/* Contact */
.contact-grid{display:grid;grid-template-columns:1.1fr .9fr;gap:36px}
.form-card{border:1px solid var(--line);border-radius:var(--radius);padding:32px;background:#fff}
.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}
.field label{display:block;font-weight:700;margin-bottom:8px}
.field input,.field select,.field textarea{
  width:100%;border:1px solid #d7dfe2;border-radius:8px;padding:12px 14px;background:#fff;outline:none
}
.field input:focus,.field select:focus,.field textarea:focus{border-color:var(--accent);box-shadow:0 0 0 3px rgba(187,111,42,.1)}
.field.full{grid-column:1/-1}
.field textarea{min-height:150px;resize:vertical}
.form-note{font-size:13px;color:var(--muted);margin-top:12px}
.contact-item{display:flex;gap:14px;margin-bottom:22px}
.contact-item .icon{flex:0 0 48px}
.contact-item strong{display:block}
.qr{
  width:160px;height:160px;border:1px dashed #adb9be;border-radius:10px;
  display:flex;align-items:center;justify-content:center;color:var(--muted);font-size:14px;text-align:center;background:var(--soft)
}

/* Footer */
.footer{background:#102b39;color:#d9e3e7;padding:54px 0 24px;margin-top:0}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:36px}
.footer h4{color:#fff;margin:0 0 14px}
.footer a{display:block;color:#b8c7ce;margin:7px 0;font-size:14px}
.footer p{color:#b8c7ce;margin:10px 0;font-size:14px}
.footer-bottom{border-top:1px solid rgba(255,255,255,.12);margin-top:36px;padding-top:20px;font-size:13px;color:#91a4ad;display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap}

/* Mobile */
@media(max-width:980px){
  .header-cta{display:none}
  .menu-btn{display:block}
  .nav{
    display:none;position:absolute;top:78px;left:0;right:0;background:#fff;border-bottom:1px solid var(--line);
    padding:12px 20px 20px;flex-direction:column;align-items:flex-start;gap:0
  }
  .nav.open{display:flex}
  .nav a{padding:12px 0;width:100%}
  .nav a.active:after{display:none}
  .hero{min-height:580px}
  .hero h1{font-size:46px}
  .grid-4{grid-template-columns:repeat(2,1fr)}
  .grid-3{grid-template-columns:repeat(2,1fr)}
  .process{grid-template-columns:repeat(2,1fr)}
  .value-box{grid-template-columns:repeat(2,1fr)}
  .value-item{border-right:0;border-bottom:1px solid var(--line)}
  .detail-layout,.contact-grid,.split{grid-template-columns:1fr}
  .side-panel{position:static}
  .article-list{grid-template-columns:repeat(2,1fr)}
  .footer-grid{grid-template-columns:repeat(2,1fr)}
}
@media(max-width:640px){
  .container{width:min(var(--max),calc(100% - 28px))}
  .section{padding:62px 0}
  .section-title{font-size:34px}
  .page-hero{padding:58px 0}
  .page-hero h1{font-size:38px}
  .hero{min-height:560px}
  .hero h1{font-size:40px}
  .hero p{font-size:18px}
  .grid-2,.grid-3,.grid-4,.article-list,.form-grid,.value-box,.process,.footer-grid{grid-template-columns:1fr}
  .value-strip{margin-top:-28px}
  .card{padding:22px}
  .form-card{padding:22px}
  .brand-cn{font-size:23px}
  .brand-en{font-size:13px}
}

.breadcrumb{padding-top:18px;padding-bottom:2px;font-size:14px;color:var(--muted)}
.breadcrumb a{color:var(--muted)}
.breadcrumb a:hover{color:var(--accent)}
.breadcrumb-sep{display:inline-block;margin:0 9px;color:#a8b2b7}
.direct-answer{margin:0 0 34px;padding:24px 26px;border-left:4px solid var(--accent);background:var(--soft);border-radius:0 10px 10px 0}
.direct-answer h2{margin-top:0}
.direct-answer p{margin-bottom:0;font-size:18px;line-height:1.8;color:var(--text)}
.source-note{font-size:14px;color:var(--muted)}
.related-links{margin-top:36px;padding-top:24px;border-top:1px solid var(--line)}
.answer-section{margin-top:38px}
.answer-section h2,.source-list h2{margin-top:0}
.article-table-wrap{margin:20px 0;overflow-x:auto;border:1px solid var(--line);border-radius:10px}
.article-table{width:100%;border-collapse:collapse;min-width:620px;background:#fff;font-size:15px}
.article-table th,.article-table td{padding:13px 15px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
.article-table th{background:var(--soft);color:var(--ink)}
.article-table tr:last-child td{border-bottom:0}
.source-list{margin-top:42px;padding-top:24px;border-top:1px solid var(--line);font-size:14px}
.source-list a{overflow-wrap:anywhere}


.brand-with-logo{align-items:center;gap:10px}
.brand-mark{width:58px;height:58px;object-fit:contain;flex:0 0 auto}
.brand-copy{display:flex;flex-direction:column;line-height:1.05;gap:4px}
.brand-copy .brand-cn{font-size:22px}
.brand-copy .brand-en{font-size:12px;letter-spacing:.08em}
@media(max-width:640px){
  .brand-mark{width:48px;height:48px}
  .brand-copy .brand-cn{font-size:19px}
  .brand-copy .brand-en{font-size:11px}
}