/* ============================================================
   Chaen Chia Fasteners — design system
   Technical-catalog aesthetic: hairline grid, mono microcopy,
   geometric display type. Brand: navy + gold on warm paper.
   ============================================================ */
:root{
  --paper:#f6f4ef;
  --card:#fffdf8;
  --ink:#152643;
  --ink-soft:rgba(21,38,67,.68);
  --navy:#1b3a6b;
  --navy-deep:#101f3c;
  --gold:#c4922f;
  --gold-soft:#efe3c8;
  --line:rgba(21,38,67,.16);
  --line-strong:rgba(21,38,67,.4);
  --disp:'Space Grotesk',sans-serif;
  --mono:'IBM Plex Mono',monospace;
  --body:'Inter',sans-serif;
  --ease:cubic-bezier(.22,.61,.36,1);
}
html[lang=zh]{
  --disp:'Space Grotesk','PingFang SC','Hiragino Sans GB','Microsoft YaHei',sans-serif;
  --mono:'IBM Plex Mono','PingFang SC','Microsoft YaHei',monospace;
  --body:'Inter','PingFang SC','Hiragino Sans GB','Microsoft YaHei',sans-serif;
}
html[lang=zh] .mono,html[lang=zh] .label,html[lang=zh] .main-nav a,
html[lang=zh] .chip,html[lang=zh] .btn,html[lang=zh] .crumb a,
html[lang=zh] .crumb span{letter-spacing:.08em}
html[lang=zh] .marquee span{letter-spacing:.1em}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  background:var(--paper);
  color:var(--ink);
  font-family:var(--body);
  font-size:16px;
  line-height:1.55;
  -webkit-font-smoothing:antialiased;
}
::selection{background:var(--gold);color:#fff}
img{display:block;max-width:100%}
a{color:inherit;text-decoration:none}
ul{list-style:none}

/* ---------- utilities ---------- */
.wrap{max-width:1440px;margin:0 auto;padding:0 clamp(20px,4vw,64px)}
.mono{
  font-family:var(--mono);
  font-size:11px;
  letter-spacing:.14em;
  text-transform:uppercase;
}
.label{
  font-family:var(--mono);
  font-size:11px;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--ink-soft);
  display:flex;align-items:center;gap:12px;
}
.label::before{content:"";width:28px;height:1px;background:var(--gold)}
.label .idx{color:var(--gold)}
.reveal{opacity:0;transform:translateY(22px);transition:opacity .7s var(--ease),transform .7s var(--ease)}
.reveal.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){
  .reveal{opacity:1;transform:none;transition:none}
  html{scroll-behavior:auto}
}

/* ---------- marquee ---------- */
.marquee{
  background:var(--navy-deep);
  color:#e9e2cf;
  overflow:hidden;
  border-bottom:1px solid var(--line);
  padding:9px 0;
  position:relative;z-index:60;
}
.marquee-track{display:flex;width:max-content;animation:mq 34s linear infinite}
.marquee span{
  font-family:var(--mono);font-size:11px;letter-spacing:.18em;text-transform:uppercase;
  white-space:nowrap;padding-right:48px;
}
.marquee b{color:var(--gold);font-weight:500}
@keyframes mq{to{transform:translateX(-50%)}}

/* ---------- header ---------- */
.site-head{
  position:sticky;top:0;z-index:50;
  background:rgba(246,244,239,.9);
  backdrop-filter:blur(12px);
  -webkit-backdrop-filter:blur(12px);
  border-bottom:1px solid var(--line);
}
.head-in{
  display:flex;align-items:stretch;justify-content:space-between;
  min-height:72px;
}
.brand{display:flex;align-items:center;gap:14px;padding:10px 0}
.brand img{width:44px;height:44px;border-radius:50%;border:1px solid var(--line)}
.brand-name{font-family:var(--disp);font-weight:700;font-size:19px;letter-spacing:-.01em;line-height:1.05}
.brand-name small{display:block;font-family:var(--mono);font-size:9.5px;letter-spacing:.22em;color:var(--ink-soft);font-weight:400;margin-top:3px}
.main-nav{display:flex;align-items:stretch}
.main-nav a{
  display:flex;align-items:center;
  padding:0 clamp(14px,2vw,28px);
  border-left:1px solid var(--line);
  font-family:var(--mono);font-size:11.5px;letter-spacing:.14em;text-transform:uppercase;
  transition:background .25s var(--ease),color .25s var(--ease);
  position:relative;
}
.main-nav a:hover{background:var(--navy);color:#f3edda}
.main-nav a.active{color:var(--gold)}
.main-nav a.active::after{
  content:"";position:absolute;left:0;right:0;bottom:-1px;height:2px;background:var(--gold);
}
.nav-toggle{
  display:none;background:none;border:none;border-left:1px solid var(--line);
  width:64px;cursor:pointer;
  font-family:var(--mono);font-size:11px;letter-spacing:.14em;text-transform:uppercase;color:var(--ink);
}
@media (max-width:900px){
  .main-nav{
    display:none;position:absolute;top:100%;left:0;right:0;
    background:var(--paper);border-bottom:1px solid var(--line);
    flex-direction:column;
  }
  .main-nav.open{display:flex}
  .main-nav a{border-left:none;border-top:1px solid var(--line);padding:18px 24px}
  .nav-toggle{display:block}
}

/* ---------- hero (home) ---------- */
.hero{
  display:grid;grid-template-columns:1.15fr .85fr;
  border-bottom:1px solid var(--line);
  min-height:min(82vh,760px);
}
.hero-copy{
  padding:clamp(40px,6vw,96px) clamp(24px,4vw,72px);
  display:flex;flex-direction:column;justify-content:center;gap:28px;
  border-right:1px solid var(--line);
}
.hero-title{
  font-family:var(--disp);font-weight:700;
  font-size:clamp(40px,5.4vw,84px);
  line-height:1.02;letter-spacing:-.025em;
}
.hero-title em{font-style:normal;color:var(--gold)}
.hero-sub{max-width:520px;color:var(--ink-soft);font-size:17px}
.hero-ctas{display:flex;gap:14px;flex-wrap:wrap}
.btn{
  display:inline-flex;align-items:center;gap:10px;
  font-family:var(--mono);font-size:11.5px;letter-spacing:.14em;text-transform:uppercase;
  padding:16px 26px;border:1px solid var(--ink);
  transition:all .25s var(--ease);cursor:pointer;background:transparent;color:var(--ink);
}
.btn:hover{background:var(--navy);border-color:var(--navy);color:#f3edda}
.btn.solid{background:var(--ink);color:#f3edda}
.btn.solid:hover{background:var(--navy);border-color:var(--navy)}
.btn .arr{transition:transform .25s var(--ease)}
.btn:hover .arr{transform:translateX(5px)}
.hero-media{position:relative;overflow:hidden;background:var(--navy-deep)}
.hero-media img{width:100%;height:100%;object-fit:cover;opacity:.92}
.hero-media .tag{
  position:absolute;left:20px;bottom:20px;
  background:rgba(16,31,60,.82);color:#e9e2cf;
  padding:10px 14px;backdrop-filter:blur(6px);
}
@media (max-width:900px){
  .hero{grid-template-columns:1fr;min-height:0}
  .hero-copy{border-right:none;border-bottom:1px solid var(--line)}
  .hero-media{min-height:320px}
}

/* ---------- stat strip ---------- */
.stats{display:grid;grid-template-columns:repeat(4,1fr);border-bottom:1px solid var(--line)}
.stat{padding:34px clamp(20px,3vw,48px);border-right:1px solid var(--line)}
.stat:last-child{border-right:none}
.stat .num{font-family:var(--disp);font-weight:700;font-size:clamp(28px,3vw,44px);letter-spacing:-.02em}
.stat .num i{font-style:normal;color:var(--gold)}
.stat .cap{margin-top:6px}
@media (max-width:900px){
  .stats{grid-template-columns:1fr 1fr}
  .stat:nth-child(2){border-right:none}
  .stat:nth-child(-n+2){border-bottom:1px solid var(--line)}
}

/* ---------- section scaffold ---------- */
.section{padding:clamp(56px,7vw,110px) 0;border-bottom:1px solid var(--line)}
.sec-head{display:flex;align-items:flex-end;justify-content:space-between;gap:24px;margin-bottom:clamp(32px,4vw,56px);flex-wrap:wrap}
.sec-title{font-family:var(--disp);font-weight:700;font-size:clamp(28px,3.6vw,52px);letter-spacing:-.02em;line-height:1.08}
.sec-title em{font-style:normal;color:var(--gold)}

/* ---------- product index table ---------- */
.pindex{border-top:1px solid var(--line-strong)}
.prow{
  display:grid;
  grid-template-columns:64px 96px 1fr minmax(120px,180px) 110px 130px 56px;
  align-items:center;gap:18px;
  padding:16px 0;
  border-bottom:1px solid var(--line);
  transition:background .25s var(--ease);
  position:relative;
}
.prow:hover{background:var(--card)}
.prow .no{font-family:var(--mono);font-size:12px;color:var(--ink-soft);padding-left:8px}
.prow .thumb{
  width:96px;height:72px;display:flex;align-items:center;justify-content:center;
  background:linear-gradient(160deg,#fffdf8,#efe9da);
  border:1px solid var(--line);overflow:hidden;
}
.prow .thumb img{max-height:64px;max-width:88%;object-fit:contain;
  filter:drop-shadow(0 6px 10px rgba(21,38,67,.18));
  transition:transform .35s var(--ease)}
.prow:hover .thumb img{transform:translateY(-3px) scale(1.04)}
.prow .name{font-family:var(--disp);font-weight:600;font-size:clamp(15px,1.5vw,20px);letter-spacing:-.01em;line-height:1.25}
.prow .cat,.prow .dia,.prow .len{font-family:var(--mono);font-size:11.5px;letter-spacing:.06em;color:var(--ink-soft);text-transform:uppercase}
.prow .arr{
  width:40px;height:40px;border:1px solid var(--line);border-radius:50%;
  display:flex;align-items:center;justify-content:center;margin-right:8px;
  transition:all .25s var(--ease);font-size:15px;
}
.prow:hover .arr{background:var(--gold);border-color:var(--gold);color:#fff;transform:rotate(-45deg)}
.pindex-head{
  display:grid;grid-template-columns:64px 96px 1fr minmax(120px,180px) 110px 130px 56px;
  gap:18px;padding:12px 0;border-bottom:1px solid var(--line-strong);
}
.pindex-head span{font-family:var(--mono);font-size:10px;letter-spacing:.16em;text-transform:uppercase;color:var(--ink-soft)}
.pindex-head .c-no{padding-left:8px}
@media (max-width:1000px){
  .pindex-head{display:none}
  .prow{grid-template-columns:72px 1fr 48px;grid-template-areas:"thumb name arr" "thumb meta arr";row-gap:4px}
  .prow .no,.pindex-head .c-no{display:none}
  .prow .thumb{grid-area:thumb;width:72px;height:88px}
  .prow .name{grid-area:name}
  .prow .cat{grid-area:meta}
  .prow .dia,.prow .len{display:none}
  .prow .arr{grid-area:arr}
}

/* ---------- filters ---------- */
.filters{display:flex;gap:10px;flex-wrap:wrap}
.chip{
  font-family:var(--mono);font-size:11px;letter-spacing:.12em;text-transform:uppercase;
  padding:10px 18px;border:1px solid var(--line);background:transparent;cursor:pointer;color:var(--ink-soft);
  transition:all .22s var(--ease);
}
.chip:hover{border-color:var(--ink);color:var(--ink)}
.chip.on{background:var(--navy);border-color:var(--navy);color:#f3edda}

/* ---------- capability grid (home) ---------- */
.cap-grid{display:grid;grid-template-columns:repeat(3,1fr);border-top:1px solid var(--line-strong);border-left:1px solid var(--line-strong)}
.cap-cell{border-right:1px solid var(--line-strong);border-bottom:1px solid var(--line-strong);background:var(--card)}
.cap-cell figure{aspect-ratio:4/3;overflow:hidden;border-bottom:1px solid var(--line)}
.cap-cell figure img{width:100%;height:100%;object-fit:cover;transition:transform .6s var(--ease)}
.cap-cell:hover figure img{transform:scale(1.05)}
.cap-body{padding:24px}
.cap-body h3{font-family:var(--disp);font-size:20px;font-weight:600;margin:10px 0 8px}
.cap-body p{color:var(--ink-soft);font-size:14.5px}
@media (max-width:900px){.cap-grid{grid-template-columns:1fr}}

/* ---------- about split ---------- */
.about{display:grid;grid-template-columns:1fr 1fr;border-top:1px solid var(--line-strong)}
.about-copy{padding:clamp(32px,4vw,64px);border-right:1px solid var(--line-strong)}
.about-copy p{color:var(--ink-soft);margin-top:18px;max-width:56ch}
.about-copy p b{color:var(--ink)}
.about-media{position:relative;min-height:380px}
.about-media img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover}
@media (max-width:900px){.about{grid-template-columns:1fr}.about-copy{border-right:none;border-bottom:1px solid var(--line-strong)}}

/* ---------- certs ---------- */
.certs{display:grid;grid-template-columns:repeat(4,1fr);border-top:1px solid var(--line-strong);border-left:1px solid var(--line-strong)}
.cert{border-right:1px solid var(--line-strong);border-bottom:1px solid var(--line-strong);padding:34px 24px;text-align:center;background:var(--card)}
.cert img{height:64px;width:auto;margin:0 auto 14px;object-fit:contain;mix-blend-mode:multiply}
.cert .mono{color:var(--ink-soft)}
@media (max-width:900px){.certs{grid-template-columns:1fr 1fr}}

/* ---------- footer / contact ---------- */
.site-foot{background:var(--navy-deep);color:#ddd6c2}
.foot-grid{display:grid;grid-template-columns:1.2fr 1fr 1fr;border-bottom:1px solid rgba(233,226,207,.14)}
.foot-cell{padding:clamp(32px,4vw,56px);border-right:1px solid rgba(233,226,207,.14)}
.foot-cell:last-child{border-right:none}
.foot-cell h4{font-family:var(--mono);font-size:11px;letter-spacing:.16em;text-transform:uppercase;color:var(--gold);margin-bottom:18px}
.foot-cell a,.foot-cell p{color:#ddd6c2;font-size:14.5px;line-height:1.9;display:block}
.foot-cell a:hover{color:var(--gold)}
.foot-brand{display:flex;align-items:center;gap:14px;margin-bottom:18px}
.foot-brand img{width:48px;height:48px;border-radius:50%}
.foot-brand .n{font-family:var(--disp);font-weight:700;font-size:20px;color:#f3edda}
.foot-bottom{display:flex;justify-content:space-between;gap:16px;padding:20px 0;flex-wrap:wrap}
.foot-bottom span{font-family:var(--mono);font-size:10.5px;letter-spacing:.14em;text-transform:uppercase;color:rgba(221,214,194,.55)}
@media (max-width:900px){.foot-grid{grid-template-columns:1fr}.foot-cell{border-right:none;border-bottom:1px solid rgba(233,226,207,.14)}}

/* ============================================================
   PRODUCT DETAIL
   ============================================================ */
.crumb{padding:18px 0;border-bottom:1px solid var(--line);display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.crumb a,.crumb span{font-family:var(--mono);font-size:10.5px;letter-spacing:.14em;text-transform:uppercase;color:var(--ink-soft)}
.crumb a:hover{color:var(--gold)}
.crumb .sep{color:var(--gold)}
.pd-hero{display:grid;grid-template-columns:1fr 1fr;border-bottom:1px solid var(--line)}
.pd-gallery{
  border-right:1px solid var(--line);
  background:
    linear-gradient(var(--line) 1px,transparent 1px) 0 0/100% 88px,
    linear-gradient(90deg,var(--line) 1px,transparent 1px) 0 0/88px 100%,
    linear-gradient(160deg,#fffdf8,#f0eadb);
  display:flex;align-items:center;justify-content:center;gap:4%;
  padding:clamp(28px,4vw,64px);min-height:520px;position:relative;
}
.pd-gallery .ph{
  max-height:min(56vh,560px);max-width:44%;object-fit:contain;
  filter:drop-shadow(0 18px 24px rgba(21,38,67,.22));
  transition:transform .4s var(--ease);
}
.pd-gallery .ph:hover{transform:translateY(-6px)}
.pd-gallery .count{position:absolute;top:16px;left:20px}
.pd-info{padding:clamp(32px,4vw,72px);display:flex;flex-direction:column;gap:26px;justify-content:center}
.pd-title{font-family:var(--disp);font-weight:700;font-size:clamp(28px,3.4vw,52px);line-height:1.06;letter-spacing:-.02em}
.pd-cat{display:inline-flex}
.pd-cat span{border:1px solid var(--gold);color:var(--gold);padding:8px 14px}
.spec-strip{display:grid;grid-template-columns:1fr 1fr;border-top:1px solid var(--line-strong);border-left:1px solid var(--line-strong)}
.spec{border-right:1px solid var(--line-strong);border-bottom:1px solid var(--line-strong);padding:14px 16px}
.spec .k{font-family:var(--mono);font-size:10px;letter-spacing:.16em;text-transform:uppercase;color:var(--ink-soft);margin-bottom:6px}
.spec .v{font-family:var(--disp);font-weight:600;font-size:16px}
@media (max-width:900px){
  .pd-hero{grid-template-columns:1fr}
  .pd-gallery{border-right:none;border-bottom:1px solid var(--line);min-height:400px}
}

/* features */
.feat-grid{display:grid;grid-template-columns:repeat(2,1fr);border-top:1px solid var(--line-strong);border-left:1px solid var(--line-strong)}
.feat{border-right:1px solid var(--line-strong);border-bottom:1px solid var(--line-strong);padding:clamp(22px,2.6vw,36px);background:var(--card);transition:background .25s var(--ease)}
.feat:hover{background:#fff}
.feat .f-no{font-family:var(--mono);font-size:11px;color:var(--gold);letter-spacing:.14em}
.feat h3{font-family:var(--disp);font-size:clamp(17px,1.6vw,21px);font-weight:600;margin:12px 0 8px;letter-spacing:-.01em}
.feat p{color:var(--ink-soft);font-size:14.5px}
@media (max-width:700px){.feat-grid{grid-template-columns:1fr}}

/* tri columns: wood / application / cert */
.tri{display:grid;grid-template-columns:repeat(3,1fr);border-top:1px solid var(--line-strong);border-left:1px solid var(--line-strong)}
.tri-col{border-right:1px solid var(--line-strong);border-bottom:1px solid var(--line-strong);padding:clamp(24px,3vw,40px)}
.tri-col h3{font-family:var(--mono);font-size:11px;letter-spacing:.16em;text-transform:uppercase;color:var(--gold);margin-bottom:20px;display:flex;align-items:center;gap:10px}
.tri-col li{padding:10px 0;border-bottom:1px dashed var(--line);font-size:14.5px;display:flex;gap:10px}
.tri-col li:last-child{border-bottom:none}
.tri-col li::before{content:"—";color:var(--gold);flex:none}
.tri-col.certcol li::before{content:"✓";color:var(--gold);font-weight:700}
@media (max-width:900px){.tri{grid-template-columns:1fr}}

/* drawing & sheet */
.drawing-box{border:1px solid var(--line-strong);background:var(--card);padding:clamp(24px,4vw,56px)}
.drawing-box img{width:100%;height:auto}
.sheet-box{border:1px solid var(--line-strong);background:var(--card);padding:clamp(12px,2vw,24px)}
.sheet-box img{width:100%;height:auto}

/* prev / next */
.pn{display:grid;grid-template-columns:1fr 1fr;border-top:1px solid var(--line-strong)}
.pn a{
  padding:clamp(28px,4vw,48px);display:flex;flex-direction:column;gap:8px;
  transition:background .25s var(--ease);
}
.pn a:hover{background:var(--card)}
.pn a.next{text-align:right;border-left:1px solid var(--line-strong)}
.pn .mono{color:var(--gold)}
.pn .t{font-family:var(--disp);font-weight:600;font-size:clamp(16px,1.8vw,22px);letter-spacing:-.01em}
@media (max-width:700px){.pn{grid-template-columns:1fr}.pn a.next{border-left:none;border-top:1px solid var(--line-strong);text-align:left}}