:root{
  --bg:#FAFAFA;
  --bg-soft:#F3F4F6;
  --surface:#FFFFFF;
  --text:#1A1A1A;
  --muted:#5C6670;
  --red:#D72828;
  --red-deep:#B91C1C;
  --red-soft:rgba(215,40,40,.08);
  --red-border:rgba(215,40,40,.22);
  --border:rgba(26,26,26,.08);
  --border-strong:rgba(26,26,26,.12);
  --footer:#2A2224;
  --footer-text:#C8C2C4;
  --card:#FFFFFF;
  --radius:14px;
  --shadow:0 12px 40px rgba(26,26,26,.08);
  --font:Inter,system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;
  /* legacy aliases mapped to red/light so older inline refs stay readable */
  --navy:var(--bg);
  --navy-2:var(--bg-soft);
  --navy-3:var(--surface);
  --cyan:var(--red);
  --electric:var(--red-deep);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:var(--font);background:var(--bg);color:var(--text);line-height:1.6;-webkit-font-smoothing:antialiased}
img{max-width:100%;height:auto;display:block}
a{color:var(--red);text-decoration:none}
a:hover{color:var(--red-deep)}
.container{width:min(1120px,92%);margin:0 auto}
.site-header{position:sticky;top:0;z-index:100;backdrop-filter:blur(14px);background:rgba(255,255,255,.92);border-bottom:1px solid var(--border)}
.header-inner{display:flex;align-items:center;justify-content:space-between;gap:1rem;padding:.85rem 0}
.brand{display:flex;align-items:center;gap:.85rem}
.brand-monolith{font-weight:800;letter-spacing:.04em;font-size:1.05rem;color:var(--text)}
.brand-monolith span{color:var(--red)}
.brand-dongsen img{height:36px;width:auto}
.brand-divider{width:1px;height:28px;background:var(--border-strong)}
.nav{display:flex;flex-wrap:wrap;gap:.85rem;align-items:center}
.nav a{color:var(--muted);font-size:.92rem;font-weight:500}
.nav a:hover,.nav a.is-active{color:var(--text)}
.lang-switch{display:flex;gap:.35rem}
.lang-switch button{background:transparent;border:1px solid var(--border-strong);color:var(--muted);border-radius:999px;padding:.25rem .55rem;cursor:pointer;font-size:.75rem}
.lang-switch button.active{border-color:var(--red);color:var(--red);background:var(--red-soft)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:.4rem;border-radius:999px;padding:.7rem 1.15rem;font-weight:700;border:0;cursor:pointer;transition:.2s}
.btn-primary{background:linear-gradient(135deg,var(--red),#E85A5A);color:#fff}
.btn-primary:hover{filter:brightness(1.06);color:#fff}
.btn-ghost{background:var(--surface);border:1px solid var(--border-strong);color:var(--text)}
.btn-ghost:hover{border-color:var(--red);color:var(--red)}

/* Hero */
.hero{position:relative;padding:3.5rem 0 2.5rem;overflow:hidden;background:linear-gradient(180deg,#FFFFFF 0%,#FAFAFA 100%)}
.hero::before{content:"";position:absolute;inset:-10% -5% auto;height:80%;background:
  radial-gradient(circle at 12% 20%,rgba(215,40,40,.10),transparent 42%),
  radial-gradient(circle at 88% 8%,rgba(215,40,40,.06),transparent 38%);
  pointer-events:none}
.hero-grid{display:grid;grid-template-columns:1.15fr .85fr;gap:2rem;align-items:center;position:relative}
.hero-eyebrow{display:inline-block;font-size:.78rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--red);margin:0 0 .75rem}
.hero h1{font-size:clamp(1.8rem,4vw,2.85rem);line-height:1.15;margin:0 0 1rem;letter-spacing:-.02em;color:var(--text)}
.hero h1 em{font-style:normal;color:var(--red)}
.hero p.lead{color:var(--muted);font-size:1.05rem;margin:0 0 1.5rem;max-width:40rem}
.hero-actions{display:flex;flex-wrap:wrap;gap:.75rem}
.hero-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:1.25rem;box-shadow:var(--shadow)}
.hero-card h3{margin:.2rem 0 .8rem;font-size:1rem;color:var(--text)}
.stat-row{display:grid;grid-template-columns:repeat(2,1fr);gap:.75rem}
.stat{background:var(--bg-soft);border-radius:10px;padding:.75rem;border:1px solid var(--border)}
.stat b{display:block;font-size:1.15rem;color:var(--text)}
.stat span{color:var(--muted);font-size:.8rem}

/* Hero media — concrete / polyaspartic scene */
.hero-media{
  position:relative;border-radius:var(--radius);overflow:hidden;
  border:1px solid var(--border);box-shadow:var(--shadow);
  aspect-ratio:16/10;background:var(--bg-soft);min-height:220px;
}
.hero-media video,.hero-media img.hero-poster{
  width:100%;height:100%;object-fit:cover;display:block;
}
.hero-media-fallback{
  position:absolute;inset:0;display:flex;align-items:flex-end;
  background:
    linear-gradient(135deg,rgba(42,34,36,.55),rgba(215,40,40,.25)),
    repeating-linear-gradient(90deg,rgba(255,255,255,.04) 0 2px,transparent 2px 6px),
    repeating-linear-gradient(0deg,rgba(0,0,0,.05) 0 1px,transparent 1px 5px),
    linear-gradient(160deg,#6B6568 0%,#9A9496 40%,#C4BDBF 100%);
  background-size:100% 100%, 12px 12px, 8px 8px, 100% 100%;
  animation:heroShift 14s ease-in-out infinite alternate;
}
.hero-media.has-media .hero-media-fallback{display:none}
.hero-media-caption{
  position:relative;z-index:2;padding:1.1rem 1.25rem;
  color:#fff;font-size:.92rem;font-weight:600;letter-spacing:.01em;
  text-shadow:0 1px 8px rgba(0,0,0,.35);max-width:22rem;
}
@keyframes heroShift{
  from{background-position:0 0,0 0,0 0,0 0}
  to{background-position:0 0,18px 8px,-10px 6px,0 0}
}

.section{padding:3.2rem 0}
.section-title{display:flex;justify-content:space-between;align-items:end;gap:1rem;margin-bottom:1.4rem}
.section-title h2{margin:0;font-size:clamp(1.35rem,2.5vw,1.85rem);color:var(--text)}
.section-title p{margin:0;color:var(--muted);max-width:34rem}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:1rem}
.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:1.1rem;transition:.2s;display:flex;flex-direction:column;gap:.55rem;min-height:160px;box-shadow:0 1px 2px rgba(26,26,26,.03)}
.card:hover{border-color:var(--red-border);transform:translateY(-2px);box-shadow:var(--shadow)}
.card .tag{font-size:.72rem;color:var(--red);text-transform:uppercase;letter-spacing:.08em;font-weight:700}
.card h3{margin:0;font-size:1.05rem;color:var(--text)}
.card p{margin:0;color:var(--muted);font-size:.92rem;flex:1}
.card .meta{font-size:.8rem;color:#7A8490}

/* Featured key grades — larger 2-col */
.featured-grades{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:1.15rem;margin-bottom:1.5rem}
@media (max-width:1100px){.featured-grades{grid-template-columns:1fr 1fr}}
@media (max-width:700px){.featured-grades{grid-template-columns:1fr}}
.card.card-featured{
  min-height:210px;padding:1.35rem 1.4rem;
  border-color:var(--red-border);background:linear-gradient(180deg,#FFFFFF, #FFF8F8);
  position:relative;
}
.card.card-featured::before{
  content:"";position:absolute;left:0;top:0;bottom:0;width:4px;
  background:var(--red);border-radius:var(--radius) 0 0 var(--radius);
}
.card.card-featured h3{font-size:1.35rem}
.card.card-featured .tag{background:var(--red-soft);display:inline-block;padding:.2rem .55rem;border-radius:999px}

table.spec{width:100%;border-collapse:collapse;background:var(--card);border-radius:var(--radius);overflow:hidden;border:1px solid var(--border)}
table.spec th,table.spec td{padding:.7rem .85rem;border-bottom:1px solid var(--border);text-align:left;font-size:.92rem}
table.spec th{background:var(--red-soft);color:var(--text);font-weight:600}
table.spec tr:hover td{background:rgba(215,40,40,.03)}
.breadcrumb{padding:1rem 0 0;color:var(--muted);font-size:.85rem}
.breadcrumb a{color:var(--muted)}
.page-hero{padding:1.5rem 0 1rem}
.page-hero h1{margin:0 0 .5rem;font-size:clamp(1.6rem,3vw,2.2rem);color:var(--text)}
.page-hero .sub{color:var(--muted);margin:0}
.note{border-left:3px solid #D4A017;background:rgba(212,160,23,.08);padding:.75rem 1rem;border-radius:0 10px 10px 0;color:#6B5A20;font-size:.9rem;margin:1rem 0}
.dual-banner{display:grid;grid-template-columns:1fr 1fr;gap:1rem}
.dual-banner .panel{border-radius:var(--radius);padding:1.25rem;border:1px solid var(--border);background:var(--surface);box-shadow:0 1px 2px rgba(26,26,26,.03)}
.dual-banner .panel.dongsen{border-color:var(--red-border);background:linear-gradient(180deg,#FFFFFF,#FFF7F7)}
.dual-banner .tag{color:var(--red)}

.footer{border-top:1px solid rgba(255,255,255,.06);padding:2.5rem 0 2rem;margin-top:2rem;background:var(--footer);color:var(--footer-text);font-size:.9rem}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr;gap:1.5rem}
.footer h4{color:#fff;margin:0 0 .7rem}
.footer a{color:var(--footer-text)}
.footer a:hover{color:#fff}
.compare-bar{display:flex;flex-wrap:wrap;gap:.5rem;margin:1rem 0}
.compare-bar label{background:var(--surface);border:1px solid var(--border);border-radius:999px;padding:.45rem .8rem;font-size:.85rem;cursor:pointer;color:var(--text)}
.compare-bar input{margin-right:.35rem}

#md-chat-launcher{position:fixed;right:1.1rem;bottom:1.1rem;z-index:200;width:58px;height:58px;border-radius:50%;border:0;background:linear-gradient(135deg,var(--red),#E85A5A);color:#fff;font-size:1.35rem;cursor:pointer;box-shadow:0 12px 30px rgba(215,40,40,.4)}
#md-chat{position:fixed;right:1.1rem;bottom:5.2rem;width:min(380px,92vw);height:min(520px,70vh);background:var(--surface);border:1px solid var(--border);border-radius:18px;display:none;flex-direction:column;z-index:200;box-shadow:var(--shadow);overflow:hidden;color:var(--text)}
#md-chat.open{display:flex}
.md-chat-head{padding:.85rem 1rem;background:linear-gradient(90deg,var(--red),#E85A5A);display:flex;justify-content:space-between;align-items:center}
.md-chat-head strong{color:#fff}
.md-chat-body{flex:1;overflow:auto;padding:1rem;display:flex;flex-direction:column;gap:.65rem;background:var(--bg)}
.md-msg{max-width:90%;padding:.65rem .8rem;border-radius:12px;font-size:.9rem}
.md-msg.bot{background:var(--surface);border:1px solid var(--border);align-self:flex-start;color:var(--text)}
.md-msg.user{background:var(--red-soft);border:1px solid var(--red-border);align-self:flex-end;color:var(--text)}
.md-chat-form{display:flex;gap:.4rem;padding:.75rem;border-top:1px solid var(--border);background:var(--surface)}
.md-chat-form input{flex:1;background:var(--bg);border:1px solid var(--border-strong);border-radius:10px;color:var(--text);padding:.65rem .75rem}
.md-chat-form button{background:var(--red);color:#fff;border:0;border-radius:10px;padding:0 .9rem;font-weight:700;cursor:pointer}
.lead-fields{display:grid;gap:.45rem;margin-top:.5rem}
.lead-fields input,.lead-fields textarea{width:100%;background:var(--surface);border:1px solid var(--border-strong);border-radius:8px;color:var(--text);padding:.5rem .65rem;font:inherit}

@media (max-width:860px){
  .hero-grid,.dual-banner,.footer-grid,.featured-grades{grid-template-columns:1fr}
  .nav{display:none}
  .nav.open{display:flex;position:absolute;top:100%;left:0;right:0;background:var(--surface);border-bottom:1px solid var(--border);padding:1rem;flex-direction:column;box-shadow:var(--shadow)}
  .menu-toggle{display:inline-flex}
}
.menu-toggle{display:none;background:transparent;border:1px solid var(--border-strong);color:var(--text);border-radius:8px;padding:.4rem .6rem}
.geo-banner{background:var(--red-soft);border-bottom:1px solid var(--red-border);padding:.55rem 0;font-size:.85rem;color:var(--red-deep)}