/* ==========================================================================
   YAOJING — shared stylesheet
   Used by all pages. Page-specific background images are passed in via the
   --banner-bg custom property on the .banner element.
   ========================================================================== */

:root{
  --ink:#0f1e2e;
  --ink-2:#1a2a3d;
  --steel:#2c3e50;
  --orange:#e8632b;
  --orange-dark:#c94e1d;
  --silver:#c8ccd0;
  --bg:#f2f4f6;
  --line:#d9dde1;
  --text:#1a2332;
  --muted:#5a6470;
  --white:#ffffff;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:'Source Sans 3',system-ui,-apple-system,Segoe UI,Roboto,sans-serif;color:var(--text);background:var(--white);line-height:1.6;font-size:16px;-webkit-font-smoothing:antialiased}
h1,h2,h3,h4{font-family:'Oswald',Impact,sans-serif;font-weight:600;line-height:1.15;letter-spacing:.01em;text-transform:uppercase}
img{max-width:100%;height:auto;display:block}
a{color:inherit;text-decoration:none}
:focus-visible{outline:2px solid var(--orange);outline-offset:2px}
.container{max-width:1240px;margin:0 auto;padding:0 32px}

/* ===== Accessibility ===== */
.skip-link{position:absolute;left:-9999px;top:0;background:var(--orange);color:#fff;padding:12px 18px;z-index:999}
.skip-link:focus{left:8px;top:8px}

/* ===== Top bar ===== */
.topbar{background:var(--ink);color:#cfd6dd;font-size:13px;padding:8px 0;border-bottom:1px solid rgba(255,255,255,.06)}
.topbar .container{display:flex;justify-content:space-between;align-items:center;gap:16px}
.topbar a{color:#fff}
.tb-note{opacity:.9;white-space:nowrap}
.topbar .right{display:flex;align-items:center;gap:6px}

/* --- top-right contact chips --- */
.tb-link{display:inline-flex;align-items:center;gap:8px;padding:5px 12px;border-radius:999px;line-height:1;white-space:nowrap;font-weight:500;transition:background .2s ease,color .2s ease}
.tb-ico{width:15px;height:15px;flex:0 0 auto;display:block}
.tb-mail{color:#dfe6ec}
.tb-mail .tb-ico{stroke:currentColor}
.tb-mail:hover{background:rgba(232,99,43,.18);color:var(--orange)}
.tb-wa{background:rgba(37,211,102,.13);color:#5fe08c}
.tb-wa .tb-ico{fill:currentColor}
.tb-wa:hover{background:rgba(37,211,102,.24);color:#8bf3ad}
.tb-sep{width:1px;height:15px;flex:0 0 auto;background:rgba(255,255,255,.15)}

/* ===== Nav ===== */
.nav{background:var(--ink);position:sticky;top:0;z-index:100;border-bottom:3px solid var(--orange)}
.nav .container{display:flex;align-items:center;justify-content:space-between;height:72px}
.logo{font-family:'Oswald',sans-serif;font-weight:700;font-size:26px;color:#fff;letter-spacing:.08em;display:flex;align-items:center;gap:10px}
.logo-mark{width:34px;height:34px;background:var(--orange);display:inline-flex;align-items:center;justify-content:center;color:#fff;font-size:16px;font-weight:700}
.nav-links{display:flex;gap:36px;list-style:none}
.nav-links a{color:#e6eaee;font-size:14px;font-weight:500;letter-spacing:.06em;text-transform:uppercase;padding:8px 0;border-bottom:2px solid transparent;transition:.2s}
.nav-links a:hover,.nav-links a[aria-current="page"]{color:var(--orange);border-bottom-color:var(--orange)}
.nav-cta{background:var(--orange);color:#fff;padding:11px 22px;font-weight:600;font-size:14px;letter-spacing:.05em;text-transform:uppercase;cursor:pointer;border:none;font-family:'Oswald',sans-serif;display:inline-block}
.nav-cta:hover{background:var(--orange-dark)}
.hamburger{display:none;background:none;border:none;color:#fff;font-size:26px;cursor:pointer}

/* ===== Hero ===== */
.hero{position:relative;min-height:640px;display:flex;align-items:center;color:#fff;overflow:hidden;background:var(--ink)}
.hero-bg{position:absolute;inset:0;background:url('site-seismic-truss.jpg') center/cover no-repeat;opacity:.6}
/* WebP 优先，浏览器不支持 image-set 时自动落回上面的 JPEG */
@supports (background-image: image-set(url("x.webp") type("image/webp"))) {
  .hero-bg{background-image:image-set(url('site-seismic-truss.webp') type('image/webp'),url('site-seismic-truss.jpg') type('image/jpeg'))}
}
.hero::after{content:'';position:absolute;inset:0;background:linear-gradient(90deg,rgba(15,30,46,.92) 0%,rgba(15,30,46,.7) 55%,rgba(15,30,46,.35) 100%)}
.hero .container{position:relative;z-index:2;padding:100px 32px}
.hero .eyebrow{color:var(--orange);font-family:'Oswald',sans-serif;font-size:14px;letter-spacing:.25em;margin-bottom:20px;font-weight:500}
.hero h1{font-size:clamp(38px,5.5vw,68px);max-width:820px;margin-bottom:24px}
.hero h1 span{color:var(--orange)}
.hero p.lead{font-size:18px;max-width:600px;color:#d6dde4;margin-bottom:36px;line-height:1.7}
.hero-actions{display:flex;gap:16px;flex-wrap:wrap}
.btn{display:inline-block;padding:14px 30px;font-family:'Oswald',sans-serif;font-weight:600;letter-spacing:.08em;text-transform:uppercase;font-size:14px;cursor:pointer;border:none;transition:.2s;text-align:center}
.btn-primary{background:var(--orange);color:#fff}
.btn-primary:hover{background:var(--orange-dark)}
.btn-ghost{background:transparent;color:#fff;border:1.5px solid rgba(255,255,255,.4)}
.btn-ghost:hover{border-color:#fff;color:#fff}

/* <picture> wrappers must not break the absolute/fill layouts of their images */
.split-card picture{position:absolute;inset:0}
.cat-img picture{display:block;width:100%;height:100%}
.about-img picture{display:block;width:100%;height:100%}

/* ===== Stats strip ===== */
.stats{background:var(--ink-2);color:#fff;border-top:1px solid rgba(255,255,255,.06)}
.stats .container{display:grid;grid-template-columns:repeat(4,1fr);gap:0;padding:0}
.stat{padding:36px 28px;border-left:1px solid rgba(255,255,255,.08)}
.stat:first-child{border-left:none}
.stat .num{font-family:'Oswald',sans-serif;font-size:42px;font-weight:600;color:var(--orange);line-height:1}
.stat .label{font-size:13px;color:#a8b3bd;margin-top:8px;letter-spacing:.05em}

/* ===== Section base ===== */
.section{padding:90px 0}
.section-head{max-width:760px;margin-bottom:56px}
.section-head .kicker{color:var(--orange);font-family:'Oswald',sans-serif;font-size:13px;letter-spacing:.25em;margin-bottom:14px;font-weight:500}
.section-head h2{font-size:clamp(28px,3.5vw,44px);margin-bottom:18px}
.section-head p{color:var(--muted);font-size:17px}

/* ===== Product split (two large cards) ===== */
.split{display:grid;grid-template-columns:1fr 1fr;gap:28px}
.split-card{position:relative;height:480px;overflow:hidden;color:#fff;display:block}
.split-card img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;transition:transform .6s}
.split-card:hover img{transform:scale(1.05)}
.split-card::after{content:'';position:absolute;inset:0;background:linear-gradient(180deg,rgba(15,30,46,.2) 0%,rgba(15,30,46,.85) 100%)}
.split-card .body{position:absolute;left:0;right:0;bottom:0;padding:36px;z-index:2}
.split-card .num{font-family:'Oswald',sans-serif;font-size:13px;letter-spacing:.2em;color:var(--orange);margin-bottom:10px;font-weight:600}
.split-card h3{font-size:30px;margin-bottom:10px}
.split-card p{font-size:15px;color:#d6dde4;margin-bottom:18px;max-width:440px}
.split-card .link{font-family:'Oswald',sans-serif;font-size:13px;letter-spacing:.15em;color:var(--orange);text-transform:uppercase;font-weight:600}

/* ===== Applications ===== */
.apps{background:var(--bg)}
.app-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;background:var(--line);border:1px solid var(--line)}
.app{background:#fff;padding:36px 30px}
.app .ico{width:44px;height:44px;color:var(--orange);margin-bottom:18px}
.app h4{font-size:18px;margin-bottom:10px}
.app p{font-size:14px;color:var(--muted)}

/* ===== Certifications ===== */
.certs{display:flex;flex-wrap:wrap;gap:14px}
.cert{border:1.5px solid var(--line);padding:14px 22px;font-family:'Oswald',sans-serif;font-size:14px;letter-spacing:.08em;font-weight:600;color:var(--steel);background:#fff}
.cert strong{color:var(--ink)}

/* ===== Footer ===== */
footer{background:var(--ink);color:#a8b3bd;padding:70px 0 0;margin-top:0}
.foot-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1.3fr;gap:48px;padding-bottom:50px;border-bottom:1px solid rgba(255,255,255,.08)}
.foot-grid h5{color:#fff;font-family:'Oswald',sans-serif;font-size:15px;letter-spacing:.1em;margin-bottom:18px;font-weight:600}
.foot-grid ul{list-style:none}
.foot-grid li{margin-bottom:10px;font-size:14px}
.foot-grid li a:hover{color:var(--orange)}
.foot-grid p{font-size:14px;line-height:1.7}
.foot-bottom{padding:22px 0;font-size:13px;display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px}
.foot-bottom a:hover{color:var(--orange)}
.wa-float{position:fixed;right:24px;bottom:24px;width:56px;height:56px;background:#25d366;border-radius:50%;display:flex;align-items:center;justify-content:center;box-shadow:0 6px 20px rgba(0,0,0,.25);z-index:99}
.wa-float svg{width:30px;height:30px;fill:#fff}

/* ===== Page banner ===== */
.banner{background:var(--ink);color:#fff;padding:80px 0;position:relative;overflow:hidden}
.banner::after{content:'';position:absolute;right:-5%;top:0;bottom:0;width:45%;background:var(--banner-bg,url('site-cable-tray.jpg')) center/cover no-repeat;opacity:.3;filter:grayscale(.3)}
.banner .container{position:relative;z-index:2}
.banner .kicker{color:var(--orange);font-family:'Oswald',sans-serif;letter-spacing:.25em;font-size:13px;margin-bottom:12px}
.banner h1{font-size:clamp(34px,4.5vw,56px);margin-bottom:14px}
.banner p{max-width:640px;color:#cfd6dd;font-size:17px}
.breadcrumbs{font-size:13px;color:#8c99a6;margin-bottom:18px}
.breadcrumbs a:hover{color:var(--orange)}
.breadcrumbs span{margin:0 8px;opacity:.6}

/* ===== Product category cards ===== */
.cat-list{display:grid;grid-template-columns:repeat(2,1fr);gap:28px}
.cat{border:1px solid var(--line);background:#fff;transition:.2s}
.cat:hover{border-color:var(--orange);box-shadow:0 8px 24px rgba(15,30,46,.06)}
.cat-img{height:220px;overflow:hidden;background:var(--bg)}
.cat-img img{width:100%;height:100%;object-fit:cover}
.cat-body{padding:26px}
.cat-body .tag{font-family:'Oswald',sans-serif;font-size:12px;color:var(--orange);letter-spacing:.15em;font-weight:600}
.cat-body h3{font-size:22px;margin:8px 0 10px}
.cat-body p{font-size:14px;color:var(--muted);margin-bottom:14px}
.cat-body ul{list-style:none;font-size:14px;color:var(--steel)}
.cat-body ul li{padding:5px 0 5px 18px;position:relative}
.cat-body ul li::before{content:'';position:absolute;left:0;top:13px;width:8px;height:2px;background:var(--orange)}

/* ===== About ===== */
.about-grid{display:grid;grid-template-columns:1.1fr 1fr;gap:60px;align-items:center}
.about-img{height:480px;overflow:hidden}
.about-img img{width:100%;height:100%;object-fit:cover}
.about-copy h2{font-size:38px;margin-bottom:20px}
.about-copy p{color:var(--muted);margin-bottom:16px}
.points{margin-top:24px}
.point{display:flex;gap:16px;padding:16px 0;border-top:1px solid var(--line)}
.point .n{font-family:'Oswald',sans-serif;color:var(--orange);font-weight:600;font-size:18px;min-width:32px}
.point h4{font-size:16px;margin-bottom:4px}
.point p{font-size:14px;margin:0}

/* ===== Projects ===== */
.proj-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.proj{border:1px solid var(--line);padding:28px;background:#fff}
.proj .flag{font-family:'Oswald',sans-serif;color:var(--orange);font-size:13px;letter-spacing:.15em;margin-bottom:10px}
.proj h4{font-size:18px;margin-bottom:8px}
.proj p{font-size:14px;color:var(--muted)}
.proj-note{margin-top:36px;color:var(--muted);font-size:14px;max-width:820px}

/* ===== Contact ===== */
.contact-grid{display:grid;grid-template-columns:1fr 1.1fr;gap:60px}
.info-block{margin-bottom:28px}
.info-block .lbl{font-family:'Oswald',sans-serif;font-size:12px;letter-spacing:.15em;color:var(--orange);margin-bottom:6px}
.info-block .val{font-size:16px;color:var(--text);font-weight:500}
.info-block .val a:hover{color:var(--orange)}
form .row{display:grid;grid-template-columns:1fr 1fr;gap:16px}
form label{display:block;font-size:13px;font-weight:600;margin-bottom:6px;color:var(--steel);letter-spacing:.02em}
form input,form select,form textarea{width:100%;padding:12px 14px;border:1px solid var(--line);background:#fff;font-family:inherit;font-size:15px;margin-bottom:16px}
form input:focus,form select:focus,form textarea:focus{outline:none;border-color:var(--orange)}
form textarea{resize:vertical;min-height:120px}
.form-note{font-size:13px;color:var(--muted);margin-top:10px}
.form-msg{display:none;margin-top:14px;padding:12px 14px;font-size:14px;border:1px solid var(--line)}
.form-msg.ok{display:block;background:#eff7ef;border-color:#9fce9f;color:#215c21}
.form-msg.err{display:block;background:#fdf1f1;border-color:#e0a8a8;color:#8c2020}
.hp{position:absolute;left:-9999px;width:1px;height:1px;overflow:hidden}

/* ===== CTA band ===== */
.cta-band{background:var(--orange);color:#fff;padding:60px 0;text-align:center}
.cta-band h2{font-size:clamp(26px,3.5vw,40px);margin-bottom:12px}
.cta-band p{font-size:17px;opacity:.95;margin-bottom:24px}
.cta-band .btn-primary{background:var(--ink);color:#fff}
.cta-band .btn-primary:hover{background:#000}

/* ===== Product spec table ===== */
.cat-spec{width:100%;border-collapse:collapse;margin:14px 0 16px;font-size:13px}
.cat-spec td{padding:7px 0;border-bottom:1px solid #eef0f2;vertical-align:top}
.cat-spec td:first-child{color:var(--muted);width:38%;font-weight:500;padding-right:10px}
.cat-spec td:last-child{color:var(--text);font-weight:500}
.cat-actions{display:flex;gap:10px;margin-top:6px}
.cat-actions a{flex:1;text-align:center;padding:9px 10px;font-size:12px;font-weight:600;letter-spacing:.05em;text-transform:uppercase;font-family:'Oswald',sans-serif;cursor:pointer;border:1.5px solid var(--line);color:var(--steel);background:#fff}
.cat-actions a:hover{border-color:var(--orange);color:var(--orange)}
.cat-actions a.primary{background:var(--ink);color:#fff;border-color:var(--ink)}
.cat-actions a.primary:hover{background:var(--orange);border-color:var(--orange);color:#fff}

/* ===== Catalog band ===== */
.catalog-band{background:var(--ink);color:#fff;padding:70px 0;margin-top:40px}
.catalog-band .container{display:grid;grid-template-columns:1.2fr 1fr;gap:60px;align-items:center}
.catalog-band h2{font-size:32px;margin-bottom:14px}
.catalog-band p{color:#cfd6dd;margin-bottom:20px}
.catalog-form{background:#fff;padding:28px;color:var(--text);position:relative}
.catalog-form label{font-size:13px;font-weight:600;display:block;margin-bottom:6px}
.catalog-form input{width:100%;padding:11px 12px;border:1px solid var(--line);margin-bottom:14px;font-size:14px}
.catalog-form .btn{width:100%}

/* ===== 404 ===== */
.err-wrap{padding:110px 0;text-align:center}
.err-wrap .code{font-family:'Oswald',sans-serif;font-size:96px;color:var(--orange);line-height:1}
.err-wrap h1{font-size:34px;margin:14px 0 16px}
.err-wrap p{color:var(--muted);margin-bottom:28px}

/* ===== Responsive ===== */
@media (max-width:900px){
  .nav-links{display:none;position:absolute;top:72px;left:0;right:0;background:var(--ink);flex-direction:column;padding:20px 32px;gap:16px;border-bottom:3px solid var(--orange)}
  .nav-links.open{display:flex}
  .hamburger{display:block}
  .stats .container{grid-template-columns:repeat(2,1fr)}
  .stat{border-left:none;border-top:1px solid rgba(255,255,255,.08)}
  .split{grid-template-columns:1fr}
  .split-card{height:360px}
  .app-grid{grid-template-columns:1fr}
  .cat-list{grid-template-columns:1fr}
  .about-grid,.contact-grid{grid-template-columns:1fr;gap:36px}
  .proj-grid{grid-template-columns:1fr}
  .foot-grid{grid-template-columns:1fr;gap:32px}
  form .row{grid-template-columns:1fr}
  .section{padding:60px 0}
  .hero .container{padding:70px 32px}
  .catalog-band .container{grid-template-columns:1fr;gap:30px}
}

/* ===== Top bar contacts — responsive ===== */
@media (max-width:900px){
  .topbar .container{justify-content:center}
  .tb-note{display:none}
  .tb-wa-num{display:none}
}
@media (max-width:400px){
  .topbar{font-size:12px;padding:6px 0}
  .tb-link{padding:4px 10px;gap:6px}
  .tb-mail-text,.tb-sep{display:none}
}