:root {
  --bg: #050f2c;
  --bg-raised: #081a45;
  --panel: rgba(11, 32, 84, .95);
  --panel-hover: rgba(15, 42, 104, .97);
  --line: #1d3a7a;
  --line-strong: #2f55a3;
  --ink: #f1f6ff;
  --muted: #b1c3e2;
  --cyan: #3fd6e6;
  --cyan-deep: #0d7f93;
  --amber: #f2b84b;
  --radius: 8px;
  --shell: 1180px;
  --header: 76px;
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", "Source Han Sans SC", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--ink); line-height: 1.75; overflow-x: hidden; }
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }
h1, h2, h3 { line-height: 1.25; margin: 0; font-weight: 700; }
p { margin: 0; }
:focus-visible { outline: 2px solid var(--cyan); outline-offset: 3px; }
.shell { width: min(var(--shell), calc(100% - 40px)); margin: 0 auto; }

/* Page-wide backdrop: stays fixed behind every section. lvh keeps it from resizing with a phone's address bar. */
.backdrop { position: fixed; top: 0; left: 0; z-index: -1; width: 100%; height: 100vh; height: 100lvh; pointer-events: none; }
.backdrop canvas { display: block; width: 100%; height: 100%; opacity: 0; transition: opacity 1s ease; }
.backdrop.live canvas { opacity: .5; }
/* Text outside a card sits on its own plate, so it stays readable when atoms drift behind it. */
.section-head, .principle, .notice, .about-grid > *, .drums, .trademark { background: rgba(5, 15, 44, .9); border-radius: var(--radius); }
.section-head { padding: 16px 20px; }
.principle { padding: 20px 20px 22px; border-radius: 0 0 var(--radius) var(--radius); }
.notice { padding: 8px 12px; }
.about-grid > *, .drums, .trademark { padding: 24px; }

/* Header */
.site-header { position: sticky; top: 0; z-index: 40; background: rgba(5, 15, 44, .9); backdrop-filter: blur(14px); border-bottom: 1px solid var(--line); }
.topbar { min-height: var(--header); display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.brand { display: flex; align-items: center; gap: 12px; font-weight: 700; font-size: 16px; line-height: 1.3; }
.brand img { width: 46px; height: 46px; object-fit: contain; flex: none; }
.brand small { display: block; color: var(--muted); font-size: 12px; font-weight: 400; margin-top: 2px; }
.nav { display: flex; align-items: center; gap: 26px; font-size: 15px; color: var(--muted); white-space: nowrap; }
.nav a { position: relative; padding: 8px 0; transition: color .18s ease; }
.nav a::after { content: ""; position: absolute; left: 0; right: 0; bottom: 2px; height: 2px; background: var(--cyan); transform: scaleX(0); transform-origin: left; transition: transform .2s ease; }
.nav a:hover, .nav a[aria-current="page"] { color: var(--ink); }
.nav a:hover::after, .nav a[aria-current="page"]::after { transform: scaleX(1); }
.menu-button { display: none; min-height: 40px; padding: 0 14px; color: var(--ink); background: var(--panel); border: 1px solid var(--line-strong); border-radius: var(--radius); font: inherit; font-size: 14px; cursor: pointer; }

/* Scene stage */
.stage { position: relative; overflow: hidden; background: var(--bg); border-bottom: 1px solid var(--line); isolation: isolate; }
.stage-home { min-height: min(760px, calc(100vh - var(--header))); display: flex; align-items: center; }
.stage-page { padding: 72px 0 64px; min-height: 440px; display: flex; align-items: center; }
.scene { position: absolute; inset: 0; z-index: -2; background-size: cover; background-position: right center; background-repeat: no-repeat; }
.scene canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; opacity: 0; transition: opacity .8s ease; }
.scene.live canvas { opacity: 1; }
.scene.live { background-image: none !important; }
.scene-foam { background-image: url("scenes/foam.svg?v=28fdd96e9c"); }
.scene-film { background-image: url("scenes/film.svg?v=28fdd96e9c"); }
.scene-cement { background-image: url("scenes/cement.svg?v=28fdd96e9c"); }
.scene-fiber { background-image: url("scenes/fiber.svg?v=28fdd96e9c"); }
.scene-web { background-image: url("scenes/web.svg?v=28fdd96e9c"); }
.scene-micelle { background-image: url("scenes/micelle.svg?v=28fdd96e9c"); }
.scene-chain { background-image: url("scenes/chain.svg?v=28fdd96e9c"); }
.stage::before { content: ""; position: absolute; inset: 0; z-index: -1; pointer-events: none; background: linear-gradient(90deg, rgba(5, 15, 44, .96) 0%, rgba(5, 15, 44, .9) 44%, rgba(5, 15, 44, 0) 62%); }
.stage-inner { position: relative; }
.scene-note { position: absolute; right: 20px; bottom: 14px; max-width: min(460px, calc(100% - 40px)); padding: 2px 10px; color: var(--muted); font-size: 12px; background: rgba(5, 15, 44, .78); border-radius: 4px; }
.eyebrow { color: var(--cyan); font-size: 14px; font-weight: 700; letter-spacing: .06em; }
.stage h1 { margin-top: 14px; }
.stage-home h1 { font-size: clamp(38px, 4.8vw, 64px); max-width: 680px; line-height: 1.16; }
.stage-page h1 { font-size: clamp(32px, 3.8vw, 50px); max-width: 780px; }
.lead { margin-top: 18px; max-width: 640px; color: var(--muted); font-size: 18px; }
.breadcrumbs { color: var(--muted); font-size: 13px; margin-bottom: 18px; }
.breadcrumbs a { color: var(--cyan); }
.breadcrumbs a:hover { text-decoration: underline; }

/* Buttons */
.cta-row { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.btn { position: relative; overflow: hidden; display: inline-flex; align-items: center; justify-content: center; min-height: 46px; padding: 0 22px; border-radius: var(--radius); border: 1px solid var(--line-strong); background: rgba(11, 32, 84, .72); color: var(--ink); font-weight: 700; font-size: 15px; cursor: pointer; transition: background .2s ease, border-color .2s ease, color .2s ease, box-shadow .2s ease, transform .2s ease; }
.btn::after { content: ""; position: absolute; top: 0; bottom: 0; left: -60%; width: 40%; background: linear-gradient(100deg, transparent, rgba(255, 255, 255, .38), transparent); transform: skewX(-18deg); pointer-events: none; }
.btn.primary { background: var(--cyan); border-color: var(--cyan); color: #04213a; }
.btn.small { min-height: 38px; padding: 0 14px; font-size: 13px; }
.btn:active { transform: scale(.97); box-shadow: none; }
.btn:focus-visible { border-color: var(--cyan); color: var(--cyan); }
.btn.primary:focus-visible { color: #04213a; box-shadow: 0 0 0 3px rgba(63, 214, 230, .35); }

/* Stats */
.stats { display: grid; grid-template-columns: repeat(4, 1fr); background: rgba(8, 26, 69, .94); border-bottom: 1px solid var(--line); }
.stat { padding: 26px 24px; border-left: 1px solid var(--line); }
.stat:first-child { border-left: 0; }
.stat strong { display: block; color: var(--cyan); font-size: 36px; line-height: 1.1; }
.stat span { display: block; margin-top: 8px; color: var(--muted); font-size: 14px; }

/* Sections */
.section { padding: 84px 0; }
.section + .section { border-top: 1px solid var(--line); }
.section-tight { padding: 60px 0; }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 32px; margin-bottom: 34px; }
.section-head h2 { font-size: clamp(26px, 3vw, 38px); }
.section-head p { max-width: 560px; color: var(--muted); }
.grid-2, .grid-3, .grid-6 { display: grid; gap: 16px; }
.grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-3, .grid-6 { grid-template-columns: repeat(3, minmax(0, 1fr)); }

/* Surfaces */
.panel { padding: 28px; background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); }
.panel h3 { font-size: 21px; margin-bottom: 12px; }
.panel p { color: var(--muted); }
.tag { display: block; color: var(--cyan); font-size: 12px; font-weight: 700; letter-spacing: .05em; margin-bottom: 8px; }
.category-card { display: flex; flex-direction: column; min-height: 320px; }
.category-card p { font-size: 14px; }
.category-card ul { margin: 16px 0 20px; padding: 0; list-style: none; display: flex; flex-wrap: wrap; gap: 6px; }
.category-card li { padding: 2px 10px; font-size: 12px; color: var(--muted); border: 1px solid var(--line-strong); border-radius: 999px; transition: border-color .2s ease, color .2s ease; }
.more { display: inline-flex; align-items: center; gap: 6px; margin-top: auto; color: var(--cyan); font-weight: 700; font-size: 14px; }
.more i { font-style: normal; transition: transform .2s ease; }
.principle { position: relative; padding-top: 20px; border-top: 2px solid var(--line-strong); }
.principle::before { content: ""; position: absolute; left: 0; right: 0; top: -2px; height: 2px; background: var(--cyan); transform: scaleX(.22); transform-origin: left; transition: transform .35s ease; }
.principle h3 { font-size: 21px; margin-bottom: 10px; }
.principle p { color: var(--muted); }
.feature-list { display: grid; gap: 10px; margin: 0; padding: 0; list-style: none; }
.feature-list li { position: relative; padding-left: 20px; color: var(--ink); }
.feature-list li::before { content: ""; position: absolute; left: 0; top: .72em; width: 8px; height: 8px; border-radius: 50%; background: var(--cyan); }

/* Products */
.layout { display: grid; grid-template-columns: 260px minmax(0, 1fr); gap: 32px; align-items: start; }
.side-nav { position: sticky; top: calc(var(--header) + 20px); padding: 10px; background: rgba(8, 26, 69, .95); border: 1px solid var(--line); border-radius: var(--radius); }
.side-nav a { display: block; padding: 10px 12px; border-radius: 6px; color: var(--muted); font-size: 14px; transition: background .2s ease, color .2s ease, padding-left .2s ease; }
.side-nav a.active { color: var(--ink); background: var(--panel-hover); font-weight: 700; box-shadow: inset 2px 0 0 var(--cyan); }
.product-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }
.product-link { display: flex; flex-direction: column; padding: 22px; background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); }
.product-link strong { display: block; font-size: 18px; line-height: 1.4; margin-bottom: 8px; transition: color .2s ease; }
.product-link .summary { color: var(--muted); font-size: 14px; margin-bottom: 14px; }
.spec-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius); }
.spec-table { width: 100%; border-collapse: collapse; background: var(--panel); }
.spec-table th, .spec-table td { padding: 14px 18px; text-align: left; border-bottom: 1px solid var(--line); vertical-align: top; transition: background .15s ease, color .15s ease; }
.spec-table th { width: 34%; color: var(--muted); font-weight: 400; }
.spec-table tr:last-child th, .spec-table tr:last-child td { border-bottom: 0; }
.notice { margin-top: 16px; color: var(--muted); font-size: 13px; }
.drums { display: grid; grid-template-columns: 300px minmax(0, 1fr); gap: 32px; align-items: center; }
.drums img, .photo { width: 100%; border-radius: var(--radius); border: 1px solid var(--line); }
.drums h2 { font-size: 26px; margin-bottom: 12px; }
.drums p { color: var(--muted); }

/* Process */
.process { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; counter-reset: step; }
.process .panel::before { counter-increment: step; content: "0" counter(step); display: block; color: var(--cyan); font-weight: 700; margin-bottom: 12px; }

/* Patents */
.patent-card { display: flex; flex-direction: column; }
.patent-card h3 { font-size: 19px; line-height: 1.45; margin-top: 12px; }
.status { display: inline-block; align-self: flex-start; padding: 2px 10px; border-radius: 999px; font-size: 12px; font-weight: 700; background: rgba(63, 214, 230, .14); color: var(--cyan); border: 1px solid rgba(63, 214, 230, .45); }
.status.history { background: rgba(242, 184, 75, .12); color: var(--amber); border-color: rgba(242, 184, 75, .45); }
.number { color: var(--muted); font-size: 14px; }
.patent-card .desc { margin: 12px 0 18px; }
.patent-card .cta-row { margin-top: auto; }
.trademark { display: grid; grid-template-columns: 180px minmax(0, 1fr); gap: 32px; align-items: center; }
.trademark img { width: 100%; border-radius: var(--radius); border: 1px solid var(--line); }
.trademark h2 { font-size: 26px; margin-bottom: 12px; }
.trademark p { color: var(--muted); }
.trademark p + p { margin-top: 10px; }

/* Brand band */
.band { position: relative; overflow: hidden; border-radius: var(--radius); border: 1px solid var(--line); min-height: 340px; display: flex; align-items: center; background: var(--bg-raised) center/cover no-repeat; }
.band::before { content: ""; position: absolute; inset: 0; background: linear-gradient(90deg, rgba(5, 15, 44, .94) 0%, rgba(5, 15, 44, .72) 52%, rgba(5, 15, 44, .1) 100%); }
.band-body { position: relative; padding: 44px; max-width: 660px; }
.band h2 { font-size: clamp(24px, 2.8vw, 34px); margin-bottom: 14px; }
.band p { font-size: 18px; color: var(--ink); }

/* About and contact */
.about-grid { display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, .9fr); gap: 40px; align-items: center; }
.about-grid h2 { font-size: clamp(26px, 3vw, 36px); margin-bottom: 18px; }
.about-grid p { color: var(--muted); font-size: 17px; }
.about-grid p + p { margin-top: 14px; }
.contact-grid { display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(0, .6fr); gap: 16px; }
.contact-grid h2 { font-size: 24px; margin-bottom: 22px; }
.contact-list { display: grid; grid-template-columns: 80px minmax(0, 1fr); gap: 12px 18px; margin: 0; }
.contact-list dt { color: var(--muted); }
.contact-list dd { margin: 0; font-weight: 700; overflow-wrap: anywhere; }
.contact-list a:hover { color: var(--cyan); }
.qr { display: grid; place-items: center; text-align: center; }
.qr img { width: 170px; height: 170px; object-fit: contain; padding: 8px; background: #fff; border-radius: var(--radius); }
.qr p { margin-top: 12px; }

/* Footer */
.site-footer { padding: 32px 0; color: var(--muted); font-size: 13px; background: rgba(8, 26, 69, .95); border-top: 1px solid var(--line); }
.footer-grid { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 18px; }
.footer-links { display: flex; flex-wrap: wrap; gap: 16px; }
.footer-links a:hover { color: var(--cyan); }

/* Interaction */
.site-header { transition: box-shadow .25s ease, background .25s ease; }
.site-header.scrolled { background: rgba(5, 15, 44, .97); box-shadow: 0 10px 30px rgba(0, 0, 0, .35); }
.site-header::after { content: ""; position: absolute; left: 0; right: 0; bottom: -1px; height: 2px; background: linear-gradient(90deg, var(--cyan-deep), var(--cyan)); box-shadow: 0 0 10px rgba(63, 214, 230, .7); transform: scaleX(var(--progress, 0)); transform-origin: left; pointer-events: none; }
.nav a { transition: color .2s ease; }
.menu-button { transition: border-color .2s ease, color .2s ease, background .2s ease; }
.panel { transition: border-color .25s ease, background .25s ease, box-shadow .25s ease, transform .25s ease; }
.category-card, .product-link { position: relative; isolation: isolate; overflow: hidden; transition: border-color .25s ease, background .25s ease, box-shadow .25s ease, transform .25s ease; }
.category-card::before, .product-link::before { content: ""; position: absolute; inset: 0; z-index: -1; opacity: 0; pointer-events: none; background: radial-gradient(300px circle at var(--mx, 50%) var(--my, 50%), rgba(63, 214, 230, .24), transparent 72%); transition: opacity .25s ease; }
.category-card:active, .product-link:active { transform: scale(.985); }
.category-card:focus-visible, .product-link:focus-visible { border-color: var(--cyan); box-shadow: 0 0 0 1px var(--cyan); }
.reveal { opacity: 0; transform: translateY(22px); }
.reveal.in { opacity: 1; transform: none; transition: opacity .6s ease var(--delay, 0s), transform .6s cubic-bezier(.2, .7, .2, 1) var(--delay, 0s); }

/* Touch screens keep a hover state after a tap, so hover styles only apply to real pointers. */
@media (hover: hover) {
  .nav a:hover { color: var(--cyan); }
  .menu-button:hover { border-color: var(--cyan); color: var(--cyan); }
  .btn:hover { border-color: var(--cyan); background: rgba(63, 214, 230, .14); color: var(--cyan); box-shadow: 0 0 0 1px var(--cyan), 0 10px 26px rgba(63, 214, 230, .26); transform: translateY(-2px); }
  .btn.primary:hover { background: #7deaf4; border-color: #7deaf4; color: #04213a; box-shadow: 0 0 0 3px rgba(63, 214, 230, .28), 0 12px 32px rgba(63, 214, 230, .5); }
  .btn:hover::after { left: 125%; transition: left .6s ease; }
  .btn:active:hover { transform: scale(.97); }
  .category-card:hover, .product-link:hover { border-color: var(--cyan); background: var(--panel-hover); box-shadow: 0 16px 40px rgba(0, 0, 0, .4), 0 0 0 1px rgba(63, 214, 230, .55), 0 0 34px rgba(63, 214, 230, .14); transform: translateY(-5px); }
  .category-card:hover::before, .product-link:hover::before { opacity: 1; }
  .category-card:hover li { border-color: rgba(63, 214, 230, .6); color: var(--ink); }
  .category-card:hover .more i, .product-link:hover .more i { transform: translateX(6px); }
  .product-link:hover strong { color: var(--cyan); }
  .panel:not(.category-card):hover { border-color: var(--line-strong); background: var(--panel-hover); }
  .principle:hover::before { transform: scaleX(1); }
  .side-nav a:not(.active):hover { color: var(--cyan); background: var(--panel); padding-left: 18px; }
  .spec-table tr:hover th, .spec-table tr:hover td { background: var(--panel-hover); color: var(--ink); }
  .stat { transition: background .25s ease; }
  .stat:hover { background: var(--panel); }
  .footer-links a, .contact-list a, .breadcrumbs a { transition: color .2s ease; }
  .contact-list a:hover { text-decoration: underline; }
}

@media (max-width: 1040px) {
  .menu-button { display: inline-flex; align-items: center; }
  .nav { display: none; position: absolute; left: 20px; right: 20px; top: calc(var(--header) - 6px); flex-direction: column; align-items: flex-start; gap: 4px; padding: 14px 18px; background: var(--bg-raised); border: 1px solid var(--line-strong); border-radius: var(--radius); }
  .nav.open { display: flex; }
  .grid-3, .grid-6, .process { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .layout { grid-template-columns: 1fr; }
  .side-nav { position: static; display: flex; flex-wrap: wrap; gap: 4px; }
  .about-grid { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  :root { --header: 68px; }
  .shell { width: calc(100% - 32px); }
  .brand { font-size: 14px; }
  .brand img { width: 40px; height: 40px; }
  .brand small { font-size: 11px; }
  .stage::before { background: rgba(5, 15, 44, .74); }
  .stage-home { min-height: 0; padding: 64px 0 76px; }
  .stage-page { padding: 48px 0 64px; min-height: 0; }
  .stage-home h1 { font-size: 36px; }
  .stage-page h1 { font-size: 30px; }
  .lead { font-size: 16px; }
  .scene-note { right: auto; left: 16px; max-width: calc(100% - 32px); }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .stat { padding: 20px 16px; }
  .stat:nth-child(odd) { border-left: 0; }
  .stat:nth-child(n+3) { border-top: 1px solid var(--line); }
  .stat strong { font-size: 30px; }
  .section { padding: 56px 0; }
  .section-tight { padding: 44px 0; }
  .section-head { display: block; margin-bottom: 26px; }
  .section-head p { margin-top: 10px; }
  .grid-2, .grid-3, .grid-6, .process, .product-list, .contact-grid, .drums, .trademark { grid-template-columns: 1fr; }
  .panel { padding: 22px; }
  .category-card { min-height: 0; }
  .band-body { padding: 26px; }
  .band::before { background: rgba(5, 15, 44, .78); }
  .band p { font-size: 16px; }
  .spec-table th { width: 42%; }
  .spec-table th, .spec-table td { padding: 12px; font-size: 14px; }
  .drums img { max-width: 280px; }
  .trademark img { max-width: 160px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .01ms !important; animation-duration: .01ms !important; }
}