/* ============================================================
   A283GrC 碳素结构钢板技术资料站 · 静态站点样式
   主色 #3b75bc 60% / 辅助 #ec5029 30% / 点缀 #f7d260 10%
   ============================================================ */

:root {
  --primary: #3b75bc;
  --primary-dark: #2f5f99;
  --primary-soft: #e8f1fa;
  --accent: #ec5029;
  --accent-soft: #fdeee9;
  --gold: #f7d260;
  --gold-soft: #fdf6e0;
  --ink: #1f2a37;
  --muted: #5b6672;
  --bg: #f5f8fc;
  --card: #ffffff;
  --line: #dbe4ee;
  --radius: 10px;
  --shadow: 0 6px 20px rgba(31, 42, 55, 0.08);
  --container: 1180px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: "Microsoft YaHei", "PingFang SC", "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
}

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

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

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

/* ---------- 顶部导航 ---------- */
.site-header {
  background: var(--primary);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 10px rgba(31, 42, 55, 0.18);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 64px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #fff;
  font-weight: 700;
  font-size: 17px;
  letter-spacing: 0.5px;
}
.brand:hover { text-decoration: none; }

.brand-mark {
  width: 34px;
  height: 34px;
  border: 2px solid var(--gold);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--gold);
  flex: 0 0 auto;
}

.brand small {
  display: block;
  font-size: 11px;
  font-weight: 400;
  opacity: 0.85;
  letter-spacing: 0.3px;
}

.nav-toggle {
  display: none;
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.4);
  border-radius: 8px;
  color: #fff;
  width: 42px;
  height: 42px;
  cursor: pointer;
  align-items: center;
  justify-content: center;
}

.main-nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  list-style: none;
}

.main-nav a {
  display: block;
  color: rgba(255, 255, 255, 0.92);
  padding: 10px 13px;
  border-radius: 8px;
  font-size: 15px;
}

.main-nav a:hover { background: rgba(255, 255, 255, 0.14); text-decoration: none; }
.main-nav a.active { background: var(--accent); color: #fff; }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  color: #fff;
  background: var(--primary-dark);
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  opacity: 0.35;
}

.hero-scrim {
  position: absolute;
  inset: 0;
  background: linear-gradient(120deg, rgba(47, 95, 153, 0.92) 0%, rgba(59, 117, 188, 0.78) 55%, rgba(59, 117, 188, 0.55) 100%);
}

.hero-inner {
  position: relative;
  padding: 64px 0 56px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--gold);
  color: var(--ink);
  font-size: 13px;
  font-weight: 700;
  padding: 5px 12px;
  border-radius: 999px;
  margin-bottom: 18px;
}

.hero h1 {
  font-size: clamp(28px, 4.2vw, 42px);
  line-height: 1.25;
  font-weight: 800;
  margin-bottom: 14px;
}

.hero .subtitle {
  font-size: clamp(15px, 2vw, 18px);
  max-width: 720px;
  opacity: 0.94;
  margin-bottom: 24px;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.hero-meta .chip {
  background: rgba(255, 255, 255, 0.14);
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 8px;
  padding: 8px 14px;
  font-size: 14px;
}

.hero-meta .chip strong { color: var(--gold); }

/* ---------- 通用区块 ---------- */
.section { padding: 48px 0; }
.section.alt { background: var(--card); }

.section-head { margin-bottom: 28px; }
.section-head h2 {
  font-size: clamp(22px, 2.6vw, 28px);
  color: var(--primary-dark);
  margin-bottom: 8px;
}
.section-head p { color: var(--muted); max-width: 760px; }

.grid {
  display: grid;
  gap: 20px;
}
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid.cols-2 { grid-template-columns: repeat(2, 1fr); }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
}

.card h3 {
  font-size: 17px;
  margin-bottom: 10px;
  color: var(--ink);
}

.card p { color: var(--muted); font-size: 15px; }

.icon-wrap {
  width: 46px;
  height: 46px;
  border-radius: 10px;
  background: var(--primary-soft);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 14px;
}
.icon-wrap.accent { background: var(--accent-soft); color: var(--accent); }
.icon-wrap.gold { background: var(--gold-soft); color: #9a7b12; }

/* ---------- 参数表 ---------- */
.table-wrap { overflow-x: auto; border-radius: var(--radius); border: 1px solid var(--line); }

table {
  width: 100%;
  border-collapse: collapse;
  background: var(--card);
  font-size: 15px;
}

caption {
  caption-side: top;
  text-align: left;
  font-weight: 700;
  padding: 12px 14px;
  color: var(--primary-dark);
  background: var(--primary-soft);
}

th, td {
  padding: 11px 14px;
  border-bottom: 1px solid var(--line);
  text-align: left;
}

th {
  background: var(--primary);
  color: #fff;
  font-weight: 600;
  white-space: nowrap;
}

td.num, th.num { text-align: right; }
td.center, th.center { text-align: center; }

tbody tr:nth-child(even) { background: #f7fafd; }
tbody tr:last-child td { border-bottom: none; }

.note {
  font-size: 13.5px;
  color: var(--muted);
  margin-top: 12px;
  padding-left: 12px;
  border-left: 3px solid var(--gold);
}

/* ---------- 指标速览 ---------- */
.metrics {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.metric {
  background: var(--card);
  border: 1px solid var(--line);
  border-top: 3px solid var(--primary);
  border-radius: var(--radius);
  padding: 20px;
}
.metric.accent { border-top-color: var(--accent); }
.metric.gold { border-top-color: var(--gold); }

.metric .value {
  font-size: 26px;
  font-weight: 800;
  color: var(--primary-dark);
}
.metric.accent .value { color: var(--accent); }
.metric .label { font-size: 13.5px; color: var(--muted); margin-top: 4px; }

/* ---------- 标签 / 关键词 ---------- */
.keywords {
  margin-top: 30px;
  padding: 20px 22px;
  background: var(--primary-soft);
  border-radius: var(--radius);
}

.keywords h3 {
  font-size: 15px;
  color: var(--primary-dark);
  margin-bottom: 12px;
}

.keyword-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  list-style: none;
}

.keyword-list a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--card);
  border: 1px solid var(--line);
  color: var(--primary);
  padding: 7px 13px;
  border-radius: 999px;
  font-size: 14px;
}

.keyword-list a:hover {
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
}

/* ---------- 步骤 / 清单 ---------- */
.check-list { list-style: none; display: grid; gap: 12px; }
.check-list li {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 18px;
}
.check-list .icon-wrap { margin-bottom: 0; width: 38px; height: 38px; flex: 0 0 auto; }
.check-list strong { display: block; margin-bottom: 2px; }
.check-list span.desc { color: var(--muted); font-size: 14.5px; }

/* ---------- 双语对照 ---------- */
.bi { display: grid; gap: 6px; }
.bi .zh { font-weight: 600; }
.bi .en { color: var(--muted); font-size: 13.5px; }

/* ---------- 页脚 ---------- */
.site-footer {
  background: var(--primary-dark);
  color: rgba(255, 255, 255, 0.9);
  margin-top: 40px;
}

.footer-contact {
  background: var(--accent);
  color: #fff;
  padding: 20px 0;
}
.footer-contact .container {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}
.footer-contact .tel {
  font-size: 18px;
  font-weight: 800;
  letter-spacing: 0.5px;
}
.footer-contact .tel a { color: #fff; }
.footer-contact .mail {
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.3px;
}
.footer-contact .mail a { color: #fff; }

.footer-main { padding: 36px 0 20px; }
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 24px;
}
.footer-grid h4 { font-size: 15px; margin-bottom: 12px; color: var(--gold); }
.footer-grid ul { list-style: none; display: grid; gap: 8px; }
.footer-grid a { color: rgba(255, 255, 255, 0.85); font-size: 14px; }
.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.18);
  padding: 16px 0;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.7);
}

.disclaimer {
  font-size: 13px;
  color: var(--muted);
  background: var(--gold-soft);
  border: 1px dashed var(--gold);
  border-radius: var(--radius);
  padding: 14px 16px;
  margin-top: 20px;
}

/* ---------- 正文图片 ---------- */
.figure {
  margin: 0 0 24px;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--card);
}
.figure-media { height: 204px; overflow: hidden; }
.figure-media img { width: 100%; height: 100%; object-fit: cover; object-position: center; }
.figure figcaption {
  padding: 10px 14px;
  font-size: 13px;
  color: var(--muted);
}

/* ---------- 面包屑 ---------- */
.breadcrumb {
  font-size: 13.5px;
  color: var(--muted);
  padding: 18px 0 0;
}
.breadcrumb a { color: var(--primary); }
.breadcrumb span { margin: 0 6px; }

/* ---------- 响应式 ---------- */
@media (max-width: 960px) {
  .grid.cols-3 { grid-template-columns: repeat(2, 1fr); }
  .metrics { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 720px) {
  .nav-toggle { display: flex; }
  .main-nav {
    display: none;
    position: absolute;
    left: 0;
    right: 0;
    top: 64px;
    background: var(--primary-dark);
    border-top: 1px solid rgba(255, 255, 255, 0.18);
  }
  .main-nav.open { display: block; }
  .main-nav ul { flex-direction: column; padding: 10px 16px 16px; }
  .main-nav a { padding: 12px 10px; }

  .grid.cols-3, .grid.cols-2 { grid-template-columns: 1fr; }
  .metrics { grid-template-columns: repeat(2, 1fr); gap: 12px; }
  .footer-grid { grid-template-columns: 1fr; }
  .hero-inner { padding: 44px 0 38px; }
  .section { padding: 34px 0; }
  .metric .value { font-size: 22px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; animation: none !important; }
}