/* Liantuo Bushing — industrial B2B static site */
:root {
  --ink: #1a2332;
  --ink-soft: #3d4a5c;
  --muted: #6b7789;
  --line: #e2e8f0;
  --line-soft: #eef2f7;
  --bg: #ffffff;
  --bg-soft: #f5f7fa;
  --accent: #2c5f8a;
  --accent-hover: #1e4a6e;
  --accent-soft: rgba(44, 95, 138, 0.08);
  --bronze: #8b7355;
  --radius: 10px;
  --max: 1120px;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); text-decoration: underline; }
ul { list-style: none; }
.container { max-width: var(--max); margin: 0 auto; padding: 0 24px; }
@media (max-width: 640px) { .container { padding: 0 16px; } }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}
.nav-bar {
  display: flex; align-items: center; justify-content: space-between;
  height: 64px; gap: 16px;
}
.logo {
  font-size: 1.05rem; font-weight: 700; color: var(--ink);
  letter-spacing: -0.02em; text-decoration: none; white-space: nowrap;
}
.logo:hover { text-decoration: none; color: var(--ink); }
.logo span { color: var(--accent); font-weight: 600; }
.nav-links { display: flex; align-items: center; gap: 28px; }
.nav-links a {
  font-size: 0.9rem; color: var(--ink-soft); font-weight: 500;
  text-decoration: none;
}
.nav-links a:hover { color: var(--accent); text-decoration: none; }
.nav-links .nav-cta {
  background: var(--accent); color: #fff; padding: 8px 16px;
  border-radius: 999px; font-size: 0.85rem; font-weight: 600;
}
.nav-links .nav-cta:hover { background: var(--accent-hover); color: #fff; text-decoration: none; }
.nav-toggle {
  display: none; background: none; border: 1px solid var(--line);
  border-radius: 8px; padding: 8px 10px; cursor: pointer;
}
.nav-toggle span { display: block; width: 20px; height: 2px; background: var(--ink); margin: 4px 0; }
@media (max-width: 768px) {
  .nav-toggle { display: block; }
  .nav-links {
    display: none; position: absolute; top: 64px; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: #fff; border-bottom: 1px solid var(--line);
    padding: 8px 16px 16px; box-shadow: 0 8px 24px rgba(0,0,0,0.06);
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 12px 4px; border-bottom: 1px solid var(--line-soft); }
  .nav-links .nav-cta { text-align: center; margin-top: 8px; border: none; }
}

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 12px 22px; border-radius: 8px; font-size: 0.95rem; font-weight: 600;
  text-decoration: none; border: 1px solid transparent; cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
  font-family: inherit;
}
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--accent); color: #fff; border-color: var(--accent); }
.btn-primary:hover { background: var(--accent-hover); color: #fff; }
.btn-secondary { background: #fff; color: var(--ink); border-color: var(--line); }
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); }
.btn-row { display: flex; flex-wrap: wrap; gap: 12px; }

/* Hero */
.hero {
  padding: 72px 0 56px;
  background: linear-gradient(180deg, var(--bg-soft) 0%, #fff 100%);
  border-bottom: 1px solid var(--line);
}
.hero-eyebrow {
  font-size: 0.75rem; font-weight: 700; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 14px;
}
.hero h1 {
  font-size: clamp(1.85rem, 4vw, 2.75rem); font-weight: 750;
  letter-spacing: -0.03em; line-height: 1.15; max-width: 18ch; margin-bottom: 16px;
}
.hero-sub {
  font-size: 1.1rem; color: var(--ink-soft); max-width: 42rem;
  margin-bottom: 28px; line-height: 1.55;
}
@media (max-width: 640px) { .hero { padding: 48px 0 40px; } }

/* Trust strip */
.trust-strip {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px;
  padding: 28px 0; border-bottom: 1px solid var(--line); background: #fff;
}
.trust-item {
  text-align: center; font-size: 0.9rem; color: var(--ink-soft);
  padding: 8px 12px;
}
.trust-item strong { display: block; color: var(--ink); font-size: 0.95rem; margin-bottom: 4px; }
@media (max-width: 640px) { .trust-strip { grid-template-columns: 1fr; gap: 8px; } }

/* Sections */
.section { padding: 64px 0; }
.section-alt { background: var(--bg-soft); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.section-head { max-width: 40rem; margin-bottom: 36px; }
.section-head.center { text-align: center; margin-left: auto; margin-right: auto; }
.section-head h2 {
  font-size: clamp(1.5rem, 3vw, 2rem); font-weight: 700;
  letter-spacing: -0.025em; margin-bottom: 10px; line-height: 1.2;
}
.section-head p { color: var(--ink-soft); font-size: 1.05rem; }
@media (max-width: 640px) { .section { padding: 48px 0; } }

/* Cards */
.card-grid { display: grid; gap: 18px; }
.card-grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.card-grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
.card-grid.cols-5 { grid-template-columns: repeat(5, 1fr); }
@media (max-width: 960px) {
  .card-grid.cols-5 { grid-template-columns: repeat(2, 1fr); }
  .card-grid.cols-3 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 640px) {
  .card-grid.cols-5, .card-grid.cols-3, .card-grid.cols-2 { grid-template-columns: 1fr; }
}
.card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 22px; display: flex; flex-direction: column; height: 100%;
  transition: box-shadow 0.2s, border-color 0.2s, transform 0.2s;
}
.card:hover { box-shadow: 0 8px 28px rgba(26,35,50,0.08); border-color: #c5d4e3; transform: translateY(-2px); }
a.card { color: inherit; text-decoration: none; }
a.card:hover { color: inherit; text-decoration: none; }
.card-tag {
  font-size: 0.7rem; font-weight: 700; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 8px;
}
.card h3 { font-size: 1.05rem; font-weight: 650; margin-bottom: 8px; letter-spacing: -0.015em; line-height: 1.3; }
.card p { font-size: 0.9rem; color: var(--ink-soft); flex: 1; margin-bottom: 14px; }
.card-link { font-size: 0.88rem; font-weight: 600; color: var(--accent); }
.card-link::after { content: " →"; }

/* Product series cards with image */
.series-card { padding: 0; overflow: hidden; }
.series-card img {
  width: 100%; aspect-ratio: 4/3; object-fit: cover; background: var(--bg-soft);
}
.series-card .series-body { padding: 18px 20px 22px; display: flex; flex-direction: column; flex: 1; }
.img-note { font-size: 0.75rem; color: var(--muted); margin-top: 6px; font-style: italic; }

/* Why list */
.why-list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.why-item {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 22px;
}
.why-item h3 { font-size: 1rem; margin-bottom: 6px; }
.why-item p { font-size: 0.9rem; color: var(--ink-soft); margin: 0; }
@media (max-width: 640px) { .why-list { grid-template-columns: 1fr; } }

/* CTA band */
.cta-band {
  padding: 56px 0; background: var(--ink); color: #fff; text-align: center;
}
.cta-band h2 { font-size: clamp(1.4rem, 3vw, 1.85rem); margin-bottom: 10px; letter-spacing: -0.02em; }
.cta-band p { color: #b8c4d4; margin-bottom: 24px; max-width: 36rem; margin-left: auto; margin-right: auto; }
.cta-band .btn-primary { background: #fff; color: var(--ink); border-color: #fff; }
.cta-band .btn-primary:hover { background: var(--bg-soft); color: var(--ink); }

/* Page header (inner) */
.page-hero {
  padding: 48px 0 36px; background: var(--bg-soft); border-bottom: 1px solid var(--line);
}
.page-hero h1 {
  font-size: clamp(1.6rem, 3.5vw, 2.35rem); font-weight: 750;
  letter-spacing: -0.03em; line-height: 1.15; margin-bottom: 12px;
}
.page-hero p { color: var(--ink-soft); font-size: 1.05rem; max-width: 42rem; }
.breadcrumb {
  font-size: 0.8rem; color: var(--muted); padding: 14px 0; border-bottom: 1px solid var(--line);
}
.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb span { color: var(--ink-soft); }

/* Product detail */
.product-layout {
  display: grid; grid-template-columns: 1fr 1.1fr; gap: 40px; align-items: start;
  padding: 48px 0;
}
.product-media {
  background: var(--bg-soft); border: 1px solid var(--line); border-radius: var(--radius);
  overflow: hidden;
}
.product-media img { width: 100%; aspect-ratio: 4/3; object-fit: cover; }
.product-media figcaption { padding: 10px 14px; font-size: 0.75rem; color: var(--muted); font-style: italic; }
.product-body h2 { font-size: 1.15rem; margin: 28px 0 10px; }
.product-body h2:first-child { margin-top: 0; }
.product-body p, .product-body li { color: var(--ink-soft); font-size: 0.95rem; }
.product-body ul { list-style: disc; padding-left: 1.25rem; margin: 8px 0 16px; }
.product-body li { margin-bottom: 4px; }
.note-box {
  background: var(--accent-soft); border-left: 3px solid var(--accent);
  padding: 12px 14px; margin: 16px 0; font-size: 0.88rem; color: var(--ink-soft);
}
.related { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 12px; }
.related a {
  font-size: 0.85rem; padding: 6px 12px; border: 1px solid var(--line);
  border-radius: 999px; color: var(--ink-soft); text-decoration: none;
}
.related a:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }
@media (max-width: 800px) {
  .product-layout { grid-template-columns: 1fr; gap: 24px; }
}

/* Contact form */
.contact-grid {
  display: grid; grid-template-columns: 0.9fr 1.3fr; gap: 40px; padding: 48px 0;
}
.contact-aside .method {
  background: var(--bg-soft); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 16px 18px; margin-bottom: 12px;
}
.contact-aside .method strong {
  display: block; font-size: 0.7rem; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--muted); margin-bottom: 4px;
}
.contact-aside .method p { font-size: 0.95rem; margin: 0; }
.form-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 28px;
}
.form-group { margin-bottom: 14px; }
.form-group label { display: block; font-size: 0.85rem; font-weight: 600; margin-bottom: 6px; }
.form-group .req { color: #b45309; font-weight: 500; font-size: 0.75rem; }
.form-group input, .form-group select, .form-group textarea {
  width: 100%; padding: 10px 12px; border: 1px solid var(--line); border-radius: 8px;
  font-size: 0.95rem; font-family: inherit; background: #fff; color: var(--ink);
}
.form-group input:focus, .form-group select:focus, .form-group textarea:focus {
  outline: 2px solid var(--accent); outline-offset: 1px; border-color: var(--accent);
}
.form-group textarea { min-height: 100px; resize: vertical; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.form-hint { font-size: 0.8rem; color: var(--muted); margin-top: 12px; }
@media (max-width: 800px) {
  .contact-grid { grid-template-columns: 1fr; gap: 28px; }
  .form-row { grid-template-columns: 1fr; }
}

/* Footer */
.site-footer {
  background: var(--bg-soft); border-top: 1px solid var(--line);
  padding: 48px 0 28px; font-size: 0.9rem;
}
.footer-grid {
  display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 32px; margin-bottom: 32px;
}
.footer-brand h3 { font-size: 1rem; margin-bottom: 10px; }
.footer-brand p { color: var(--ink-soft); font-size: 0.88rem; max-width: 28ch; }
.footer-col h4 {
  font-size: 0.72rem; letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--muted); margin-bottom: 12px;
}
.footer-col a {
  display: block; color: var(--ink-soft); margin-bottom: 8px; text-decoration: none; font-size: 0.88rem;
}
.footer-col a:hover { color: var(--accent); }
.footer-bottom {
  border-top: 1px solid var(--line); padding-top: 20px;
  font-size: 0.78rem; color: var(--muted); line-height: 1.55;
}
.footer-bottom p + p { margin-top: 8px; }
@media (max-width: 800px) {
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 24px; }
}
@media (max-width: 480px) {
  .footer-grid { grid-template-columns: 1fr; }
}

/* Misc */
.prose { max-width: 42rem; }
.prose p { color: var(--ink-soft); margin-bottom: 14px; }
.prose ul { list-style: disc; padding-left: 1.25rem; margin-bottom: 14px; }
.prose li { color: var(--ink-soft); margin-bottom: 4px; }
.muted { color: var(--muted); }
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); border: 0;
}

/* Spec / size tables */
.size-section {
  padding: 0 0 48px;
  margin-top: -8px;
}
.size-section h2 {
  font-size: 1.25rem;
  margin: 0 0 10px;
}
.size-section .size-intro {
  color: var(--ink-soft);
  font-size: 0.9rem;
  margin-bottom: 16px;
  max-width: 62rem;
}
.size-section h3 {
  font-size: 1.05rem;
  margin: 28px 0 8px;
}
.size-section .tol-note {
  font-size: 0.85rem;
  color: var(--ink-soft);
  margin: 0 0 12px;
}
.size-table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  margin-bottom: 8px;
  background: #fff;
}
.size-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
  min-width: 360px;
}
.size-table th,
.size-table td {
  padding: 8px 12px;
  text-align: left;
  border-bottom: 1px solid var(--line-soft);
  white-space: nowrap;
}
.size-table th {
  background: var(--bg-soft);
  font-weight: 600;
  color: var(--ink);
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.size-table td { color: var(--ink-soft); }
.size-table tbody tr:last-child td { border-bottom: none; }
.size-table tbody tr:hover td { background: var(--accent-soft); }
.size-table .num { font-variant-numeric: tabular-nums; text-align: right; }
.size-disclaimer {
  font-size: 0.8rem;
  color: var(--muted);
  margin-top: 12px;
  max-width: 62rem;
}