:root {
  --brand: #1456c4;
  --brand-dark: #0d3a8a;
  --accent: #ff6a00;
  --bg: #f5f7fb;
  --text: #1f2733;
  --muted: #6b7686;
  --line: #e3e8f0;
  --radius: 12px;
  --max: 1140px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

.container { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  background: #fff;
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 50;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.logo { font-size: 20px; font-weight: 800; color: var(--brand-dark); letter-spacing: .5px; }
.logo span { color: var(--accent); }
.nav { display: flex; gap: 28px; }
.nav a { color: var(--text); font-weight: 500; padding: 6px 0; position: relative; }
.nav a:hover, .nav a.active { color: var(--brand); }
.nav a.active::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -2px;
  height: 3px; background: var(--brand); border-radius: 2px;
}
.menu-toggle { display: none; background: none; border: 0; font-size: 24px; cursor: pointer; }

/* Language switch */
.lang-switch {
  font-size: 13px; font-weight: 600; color: var(--brand);
  padding: 4px 12px; border: 1px solid var(--brand); border-radius: 999px;
  white-space: nowrap; transition: .2s;
}
.lang-switch:hover { background: var(--brand); color: #fff; }

/* Hero */
.hero {
  background: linear-gradient(120deg, var(--brand) 0%, var(--brand-dark) 100%);
  color: #fff;
  padding: 72px 0;
}
.hero h1 { font-size: 38px; margin-bottom: 16px; line-height: 1.3; }
.hero p { font-size: 17px; opacity: .92; max-width: 640px; }
.hero .cta { margin-top: 28px; display: flex; gap: 14px; flex-wrap: wrap; }
.btn {
  display: inline-block; padding: 12px 26px; border-radius: 999px;
  font-weight: 600; transition: .2s; cursor: pointer; border: 0;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: #e85f00; }
.btn-ghost { background: rgba(255,255,255,.15); color: #fff; border: 1px solid rgba(255,255,255,.4); }
.btn-ghost:hover { background: rgba(255,255,255,.28); }

/* Sections */
section { padding: 60px 0; }
.section-head { text-align: center; margin-bottom: 40px; }
.section-head h2 { font-size: 28px; color: var(--brand-dark); }
.section-head p { color: var(--muted); margin-top: 8px; }

/* Advantages */
.adv-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.adv-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px 22px; transition: .2s;
}
.adv-card:hover { transform: translateY(-4px); box-shadow: 0 10px 26px rgba(20,86,196,.1); }
.adv-card h3 { color: var(--brand); font-size: 18px; margin-bottom: 10px; }
.adv-card p { color: var(--muted); font-size: 14px; }

/* Product grid */
.filter-bar { display: flex; gap: 10px; flex-wrap: wrap; justify-content: center; margin-bottom: 34px; }
.filter-btn {
  padding: 8px 18px; border: 1px solid var(--line); background: #fff;
  border-radius: 999px; cursor: pointer; font-size: 14px; color: var(--muted);
}
.filter-btn.active, .filter-btn:hover { background: var(--brand); color: #fff; border-color: var(--brand); }

.product-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.product-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  overflow: hidden; transition: .2s; display: flex; flex-direction: column;
}
.product-card:hover { transform: translateY(-4px); box-shadow: 0 12px 30px rgba(20,86,196,.12); }
.product-media {
  aspect-ratio: 1/1; background: linear-gradient(135deg,#eef3fb,#dfe8f7);
  display: flex; align-items: center; justify-content: center; position: relative;
}
.product-media img { width: 100%; height: 100%; object-fit: cover; position: relative; z-index: 1; }
.product-media .ph { position: absolute; z-index: 0; color: var(--brand); font-weight: 700; font-size: 15px; opacity: .5; }
.product-body { padding: 18px 18px 22px; flex: 1; display: flex; flex-direction: column; }
.product-body h3 { font-size: 17px; margin-bottom: 8px; }
.product-body .summary { color: var(--muted); font-size: 13px; flex: 1; }
.product-tags { margin-top: 12px; display: flex; gap: 6px; flex-wrap: wrap; }
.tag { font-size: 12px; background: #eef3fb; color: var(--brand); padding: 3px 10px; border-radius: 999px; }
.product-body .more { margin-top: 14px; color: var(--brand); font-weight: 600; font-size: 14px; }

/* Product detail */
.detail { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: start; }
.detail-media-wrap { display: flex; flex-direction: column; gap: 16px; }
.detail-media {
  aspect-ratio: 1/1; background: linear-gradient(135deg,#eef3fb,#dfe8f7);
  border-radius: var(--radius); display: flex; align-items: center; justify-content: center;
  overflow: hidden;
}
.detail-media img { width: 100%; height: 100%; object-fit: cover; position: relative; z-index: 1; }
.detail-media .ph { position: absolute; z-index: 0; color: var(--brand); font-weight: 700; opacity: .5; }
.detail-info h1 { font-size: 26px; color: var(--brand-dark); margin-bottom: 10px; }
.detail-info .lead { color: var(--muted); margin-bottom: 18px; }
.detail-info .tags { margin-bottom: 20px; }
.detail-info h3 { font-size: 16px; margin: 22px 0 10px; color: var(--brand); }
.feature-list { list-style: none; }
.feature-list li { padding-left: 22px; position: relative; margin-bottom: 8px; }
.feature-list li::before { content: "✓"; color: var(--accent); position: absolute; left: 0; font-weight: 700; }
.spec-table { width: 100%; border-collapse: collapse; }
.spec-table td { padding: 10px 12px; border-bottom: 1px solid var(--line); font-size: 14px; }
.spec-table td:first-child { color: var(--muted); width: 38%; }

/* Gallery */
.gallery {
  display: flex; gap: 10px; flex-wrap: wrap; margin-top: 8px;
}
.gallery-thumb {
  width: 72px; height: 72px; object-fit: cover; border-radius: 8px;
  border: 2px solid var(--line); cursor: pointer; transition: .2s;
}
.gallery-thumb:hover { border-color: var(--brand); }
.gallery-thumb.active { border-color: var(--brand); box-shadow: 0 0 0 2px rgba(20,86,196,.2); }

/* Param notes */
.param-notes { margin-top: 16px; padding: 12px 16px; background: #f8f9fb; border-radius: 8px; }
.param-note { font-size: 13px; color: var(--muted); margin-bottom: 4px; }
.custom-note { font-size: 13px; color: var(--brand); font-weight: 500; }

/* Image note */
.img-note {
  margin-top: 12px; font-size: 13px; color: var(--muted);
  padding: 8px 12px; background: #f8f9fb; border-radius: 6px;
}

/* Scale warning */
.scale-warning {
  background: #fff8e1;
  border: 2px solid #ffc107;
  border-radius: 8px;
  padding: 14px 18px;
  margin: 20px 0;
  font-size: 14px;
  font-weight: 700;
  color: #b00020;
  line-height: 1.6;
}

/* Contact */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; }
.info-list { list-style: none; }
.info-list li { padding: 14px 0; border-bottom: 1px solid var(--line); display: flex; gap: 12px; }
.info-list .k { color: var(--brand); font-weight: 600; min-width: 64px; }

/* WeChat QR */
.wechat-box {
  margin-top: 24px; text-align: center;
}
.wechat-box img {
  width: 180px; height: 180px; border-radius: 12px;
  border: 1px solid var(--line); margin: 0 auto;
}
.wechat-box p {
  margin-top: 10px; font-size: 14px; color: var(--brand); font-weight: 600;
}

.form-box { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; }
.form-box label { display: block; font-size: 14px; margin: 14px 0 6px; color: var(--text); }
.form-box input, .form-box textarea {
  width: 100%; padding: 11px 12px; border: 1px solid var(--line); border-radius: 8px;
  font-size: 14px; font-family: inherit;
}
.form-box input:focus, .form-box textarea:focus { outline: none; border-color: var(--brand); }
.form-box textarea { resize: vertical; min-height: 90px; }
.form-note { font-size: 13px; color: var(--muted); margin-top: 12px; }

/* Downloads */
.downloads-empty {
  text-align: center; padding: 60px 20px;
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
}
.downloads-empty p { color: var(--muted); font-size: 15px; }

/* Footer */
.site-footer { background: var(--brand-dark); color: #cdd8ef; padding: 40px 0 24px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 30px; }
.site-footer h4 { color: #fff; margin-bottom: 14px; font-size: 15px; }
.site-footer a { color: #cdd8ef; font-size: 14px; display: block; margin-bottom: 8px; }
.site-footer a:hover { color: #fff; }
.footer-bottom { text-align: center; margin-top: 30px; padding-top: 18px; border-top: 1px solid rgba(255,255,255,.15); font-size: 13px; color: #9fb0d0; }
.footer-icp { margin-top: 8px; }
.footer-icp a { color: #9fb0d0; text-decoration: none; transition: color .2s; }
.footer-icp a:hover { color: #fff; }

/* Responsive */
@media (max-width: 900px) {
  .adv-grid { grid-template-columns: repeat(2, 1fr); }
  .product-grid { grid-template-columns: repeat(2, 1fr); }
  .detail, .contact-grid, .footer-grid { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .nav { display: none; position: absolute; top: 64px; left: 0; right: 0;
    background: #fff; flex-direction: column; padding: 10px 20px; gap: 4px;
    box-shadow: 0 8px 20px rgba(0,0,0,.08); }
  .nav.open { display: flex; }
  .menu-toggle { display: block; }
  .hero h1 { font-size: 28px; }
  .adv-grid, .product-grid { grid-template-columns: 1fr; }
  .lang-switch { font-size: 12px; padding: 3px 10px; }
  .gallery-thumb { width: 56px; height: 56px; }
  .header-inner { height: 56px; }
  .nav { top: 56px; }
}