:root {
  --bg: #ffffff;
  --bg-alt: #f3f7f5;
  --ink: #0f1f1c;
  --ink-soft: #41564f;
  --primary: #0f766e;
  --primary-dark: #0b5650;
  --accent: #16a34a;
  --line: #d9e4df;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(15, 31, 28, 0.08);
  --maxw: 1120px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

img, video { max-width: 100%; display: block; }

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }

.skip-link {
  position: absolute; left: -999px; top: 0; background: var(--primary); color: #fff;
  padding: 10px 16px; z-index: 100; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(160%) blur(8px);
  border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 68px; gap: 16px; }
.brand { display: flex; align-items: center; gap: 12px; color: var(--ink); font-weight: 700; }
.brand:hover { text-decoration: none; }
.brand-mark {
  display: inline-grid; place-items: center;
  background: var(--primary); color: #fff; font-size: 12px; letter-spacing: 1px;
  padding: 8px 10px; border-radius: 10px; font-weight: 800;
}
.brand-text { display: flex; flex-direction: column; line-height: 1.1; font-size: 16px; }
.brand-text small { font-weight: 500; font-size: 11px; color: var(--ink-soft); letter-spacing: .5px; }

.primary-nav { display: flex; align-items: center; gap: 22px; }
.primary-nav a { color: var(--ink-soft); font-size: 15px; font-weight: 600; }
.primary-nav a:hover { color: var(--primary); text-decoration: none; }
.nav-cta {
  background: var(--primary); color: #fff !important; padding: 9px 16px; border-radius: 999px;
}
.nav-cta:hover { background: var(--primary-dark); }

.nav-toggle {
  display: none; border: 1px solid var(--line); background: #fff; color: var(--ink);
  padding: 8px 14px; border-radius: 10px; font-weight: 600; cursor: pointer;
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  /* 原 hero 背景图 yz_002.jpg 在发布物中缺失（线上源页同样 404），改为品牌渐变兜底，
     保证不出现破图且白字可读。若要换真实工厂/设备大图，把下面这行的渐变改为以
     assets/img 下图片作背景的写法即可（保留同等深色调，以维持白字可读）。 */
  background: linear-gradient(135deg, #0c3b37 0%, #14564f 55%, #0a2b28 100%);
  background-color: #0c3b37;
  color: #fff;
  padding: clamp(80px, 12vw, 160px) 0 clamp(64px, 9vw, 120px);
}
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, rgba(5, 24, 21, 0.86) 0%, rgba(5, 24, 21, 0.62) 55%, rgba(5, 24, 21, 0.35) 100%);
}
.hero-inner { position: relative; z-index: 1; }
.hero .eyebrow { color: #9cfce0; }
.hero h1 { color: #fff; }
.hero .lede { color: rgba(255, 255, 255, 0.92); }
.hero .btn-ghost { background: rgba(255, 255, 255, 0.12); color: #fff; border-color: rgba(255, 255, 255, 0.45); }
.hero .btn-ghost:hover { background: rgba(255, 255, 255, 0.22); border-color: rgba(255, 255, 255, 0.7); }
.eyebrow, .section-eyebrow {
  text-transform: uppercase; letter-spacing: 1.5px; font-size: 12.5px; font-weight: 700;
  color: var(--primary); margin: 0 0 12px;
}
.hero h1 {
  font-size: clamp(30px, 5vw, 52px); line-height: 1.12; margin: 0 0 18px; max-width: 18ch;
  letter-spacing: -0.5px;
}
.lede { font-size: clamp(16px, 2vw, 20px); color: var(--ink-soft); max-width: 56ch; margin: 0 0 28px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 13px 22px; border-radius: 999px; font-weight: 700; font-size: 15px; cursor: pointer;
  border: 1px solid transparent; transition: transform .15s ease, background .15s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-ghost { background: #fff; color: var(--primary); border-color: var(--line); }
.btn-ghost:hover { border-color: var(--primary); }

/* ---------- Sections ---------- */
.section { padding: clamp(48px, 7vw, 92px) 0; }
.section-alt { background: var(--bg-alt); }
.section h2 { font-size: clamp(24px, 3.4vw, 36px); line-height: 1.25; margin: 0 0 18px; letter-spacing: -0.2px; max-width: 26ch; }
.section-note { color: var(--ink-soft); margin: 0 0 28px; max-width: 64ch; }
.sub { font-size: 18px; margin: 0 0 10px; }

.group {
  font-size: 20px;
  color: var(--primary-dark);
  margin: 34px 0 14px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--line);
}

.stat-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 34px;
  text-align: center;
}
.stat { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 18px 12px; }
.stat strong { display: block; font-size: 28px; color: var(--primary); margin-bottom: 4px; }
.stat span { font-size: 14px; color: var(--ink-soft); }

.craft-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 18px;
}
.craft-grid figure { margin: 0; }
.craft-grid img { width: 100%; height: 220px; object-fit: cover; border-radius: var(--radius); border: 1px solid var(--line); }

.gallery {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}
.gallery figure { margin: 0; }
.gallery img { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; border-radius: var(--radius); border: 1px solid var(--line); }
.gallery figure:first-child { grid-column: span 2; grid-row: span 2; }
.gallery figure:first-child img { aspect-ratio: initial; height: 100%; min-height: 300px; }

.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(24px, 4vw, 56px); align-items: start; }
.grid-2 p { color: var(--ink-soft); }
.grid-2 p + p { margin-top: 14px; }

.pillars { list-style: none; margin: 0; padding: 0; display: grid; gap: 14px; }
.pillars li { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; }
.pillars strong { display: block; margin-bottom: 4px; }
.pillars span { color: var(--ink-soft); font-size: 14.5px; }

/* ---------- Cards ---------- */
.cards { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin-top: 34px; }
.card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; box-shadow: var(--shadow); }
.card h3 { margin: 0 0 8px; font-size: 19px; }
.card p { margin: 0; color: var(--ink-soft); font-size: 15px; }

/* ---------- Products ---------- */
.product-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; margin-top: 26px; }
.product { display: flex; flex-direction: column; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); }
.product img { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; border-bottom: 1px solid var(--line); }
.product-body { padding: 16px 18px 18px; }
.product h3 { margin: 0 0 6px; font-size: 17px; }
.product p { margin: 0; color: var(--ink-soft); font-size: 14px; }

.about-media { margin-top: 28px; }
.about-media figure { margin: 0; }
.about-media img { width: 100%; max-height: 360px; object-fit: cover; border-radius: var(--radius); border: 1px solid var(--line); }

/* ---------- Engineering ---------- */
.checks { margin: 0; padding-left: 20px; color: var(--ink-soft); }
.checks li { margin-bottom: 8px; }
.export-note {
  margin-top: 26px; background: #fff; border: 1px dashed var(--line); border-radius: var(--radius);
  padding: 16px 18px; color: var(--ink-soft); font-size: 15px;
}

/* ---------- Process steps ---------- */
.steps { list-style: none; margin: 26px 0 0; padding: 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; counter-reset: s; }
.steps li { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; display: flex; flex-direction: column; gap: 6px; }
.step-no { color: var(--primary); font-weight: 800; font-size: 22px; }
.steps strong { font-size: 16px; }
.steps span:last-child { color: var(--ink-soft); font-size: 14px; }

/* ---------- Videos ---------- */
.video-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; margin-top: 26px; }
.video { margin: 0; }
.video video { width: 100%; border-radius: var(--radius); background: #0f1f1c; border: 1px solid var(--line); }
.video figcaption { margin-top: 10px; color: var(--ink-soft); font-size: 14px; font-weight: 600; }

/* ---------- Why ---------- */
.why-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; margin-top: 24px; }
.why { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; }
.why strong { display: block; margin: 6px 0 8px; font-size: 17px; }
.why p { margin: 0; color: var(--ink-soft); font-size: 14.5px; }

/* ---------- Contact ---------- */
.contact { background: linear-gradient(180deg, #ffffff, #eef5f2); }
.contact-list { list-style: none; margin: 18px 0 0; padding: 0; display: grid; gap: 14px; }
.contact-list span { display: block; text-transform: uppercase; letter-spacing: 1px; font-size: 11.5px; font-weight: 700; color: var(--primary); margin-bottom: 4px; }
.contact-list li { color: var(--ink-soft); }

.form { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; box-shadow: var(--shadow); }
.field { margin-bottom: 14px; display: flex; flex-direction: column; gap: 6px; }
.field label { font-size: 14px; font-weight: 600; }
.field input, .field textarea {
  font: inherit; color: var(--ink); padding: 11px 13px; border: 1px solid var(--line);
  border-radius: 10px; background: #fff; width: 100%; resize: vertical;
}
.field input:focus, .field textarea:focus { outline: 3px solid rgba(15, 118, 110, 0.25); border-color: var(--primary); }
.form-status { margin: 6px 0 0; font-weight: 600; min-height: 1.2em; }
.form-status.ok { color: var(--accent); }
.form-status.err { color: #c0392b; }
.form-hint { color: var(--ink-soft); font-size: 12.5px; margin: 10px 0 0; }

/* ---------- Footer ---------- */
.site-footer { background: #0f1f1c; color: #cfe0da; padding: 34px 0; }
.footer-inner p { margin: 6px 0; font-size: 14px; }
.site-footer .brand-text { color: #fff; font-size: 18px; font-weight: 700; display: flex; flex-direction: column; }
.site-footer .brand-text small { color: #9fc4b9; font-weight: 500; font-size: 12px; }
.copyright { color: #8fb0a6 !important; }

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .nav-toggle { display: inline-block; }
  .primary-nav {
    position: absolute; top: 68px; left: 0; right: 0; flex-direction: column; align-items: stretch;
    gap: 0; background: #fff; border-bottom: 1px solid var(--line); padding: 8px 22px 16px;
    display: none;
  }
  .primary-nav.open { display: flex; }
  .primary-nav a { padding: 12px 0; border-bottom: 1px solid var(--line); }
  .nav-cta { text-align: center; margin-top: 10px; }
  .hero h1 { max-width: 16ch; }
  .grid-2, .cards, .steps, .video-grid, .why-grid, .stat-row, .craft-grid, .gallery { grid-template-columns: 1fr; }
  .product-grid { grid-template-columns: repeat(2, 1fr); }
  .gallery figure:first-child { grid-column: span 1; grid-row: span 1; }
  .gallery figure:first-child img { aspect-ratio: 4/3; height: auto; min-height: 0; }
}
@media (max-width: 560px) {
  .product-grid, .steps { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .btn:hover { transform: none; }
}

:focus-visible { outline: 3px solid rgba(15, 118, 110, 0.45); outline-offset: 2px; }