/* ============================================================
   电焊工安全知识分享 - 全站样式
   纯静态 · 无后台 · 无外部依赖
   ============================================================ */

:root {
  --navy: #16283c;
  --navy-2: #1f3a55;
  --orange: #f57c00;
  --orange-dark: #d96600;
  --yellow: #ffc107;
  --bg: #f5f7fa;
  --card: #ffffff;
  --text: #2b3440;
  --muted: #6b7684;
  --line: #e3e8ee;
  --radius: 12px;
  --shadow: 0 2px 12px rgba(22, 40, 60, .08);
  --shadow-lg: 0 10px 30px rgba(22, 40, 60, .14);
  --max: 1120px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Segoe UI", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.75;
  font-size: 16px;
}

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

img, svg { max-width: 100%; vertical-align: middle; }

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

/* ---------- 顶部导航 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

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

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 18px;
  color: var(--navy);
  white-space: nowrap;
}

.brand .mark {
  width: 34px;
  height: 34px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--orange), var(--yellow));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  flex: none;
}

.brand:hover { text-decoration: none; }

.nav-links {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
}

.nav-links a {
  padding: 7px 13px;
  border-radius: 8px;
  color: var(--muted);
  font-size: 15px;
  transition: all .18s ease;
  white-space: nowrap;
}

.nav-links a:hover {
  color: var(--orange-dark);
  background: #fff4e5;
  text-decoration: none;
}

.nav-links a.active {
  color: #fff;
  background: var(--orange);
  font-weight: 600;
}

/* ---------- Hero ---------- */
.hero {
  background:
    radial-gradient(1200px 400px at 85% -10%, rgba(255, 193, 7, .18), transparent 60%),
    linear-gradient(135deg, var(--navy) 0%, var(--navy-2) 60%, #2a4a6b 100%);
  color: #fff;
  padding: 76px 0 64px;
  position: relative;
  overflow: hidden;
}

.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(rgba(255,255,255,.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.04) 1px, transparent 1px);
  background-size: 44px 44px;
  pointer-events: none;
}

.hero .container { position: relative; z-index: 1; }

.hero .tag {
  display: inline-block;
  padding: 5px 14px;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, .35);
  font-size: 13px;
  letter-spacing: 2px;
  color: var(--yellow);
  margin-bottom: 18px;
}

.hero h1 {
  font-size: 40px;
  line-height: 1.3;
  letter-spacing: 1px;
  margin-bottom: 14px;
}

.hero h1 .hl { color: var(--yellow); }

.hero p {
  max-width: 720px;
  color: #c7d3e0;
  font-size: 17px;
}

.hero-actions { margin-top: 28px; display: flex; gap: 14px; flex-wrap: wrap; }

/* ---------- 页面级 hero（内页） ---------- */
.page-hero {
  background: linear-gradient(135deg, var(--navy) 0%, var(--navy-2) 100%);
  color: #fff;
  padding: 48px 0;
}

.page-hero h1 { font-size: 30px; margin-bottom: 8px; }
.page-hero p { color: #b9c7d6; font-size: 15.5px; max-width: 760px; }

.page-hero .crumb {
  font-size: 13px;
  color: #8fa4ba;
  margin-bottom: 12px;
}
.page-hero .crumb a { color: #cfdcea; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 26px;
  border-radius: 10px;
  font-size: 15.5px;
  font-weight: 600;
  transition: all .2s ease;
  border: none;
  cursor: pointer;
}

.btn:hover { text-decoration: none; transform: translateY(-2px); box-shadow: var(--shadow-lg); }

.btn-primary { background: var(--orange); color: #fff; }
.btn-primary:hover { background: var(--orange-dark); }

.btn-ghost {
  background: rgba(255, 255, 255, .08);
  color: #fff;
  border: 1px solid rgba(255, 255, 255, .35);
}

/* ---------- 通用 section ---------- */
section.section { padding: 64px 0; }
section.section.alt { background: #eef2f6; }

.section-head { text-align: center; margin-bottom: 42px; }

.section-head .kicker {
  color: var(--orange-dark);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 3px;
  text-transform: uppercase;
}

.section-head h2 {
  font-size: 30px;
  color: var(--navy);
  margin: 8px 0 10px;
}

.section-head p { color: var(--muted); max-width: 640px; margin: 0 auto; }

/* ---------- 卡片网格 ---------- */
.grid { display: grid; gap: 22px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 28px;
  border: 1px solid var(--line);
  transition: all .22s ease;
}

.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: #f3d5ad; }

.card .icon {
  width: 50px;
  height: 50px;
  border-radius: 12px;
  background: #fff2df;
  color: var(--orange-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  margin-bottom: 16px;
}

.card h3 { font-size: 18.5px; color: var(--navy); margin-bottom: 10px; }
.card p { color: var(--muted); font-size: 15px; }

.card .more {
  display: inline-block;
  margin-top: 14px;
  font-weight: 600;
  font-size: 14.5px;
}

/* ---------- 文章内容块 ---------- */
.article { max-width: 860px; margin: 0 auto; }

.block {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 32px 34px;
  margin-bottom: 26px;
}

.block h2 {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 22px;
  color: var(--navy);
  margin-bottom: 18px;
}

.block h2 .num {
  width: 34px;
  height: 34px;
  flex: none;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--orange), var(--yellow));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  font-weight: 700;
}

.block h3 { font-size: 17px; color: var(--navy-2); margin: 20px 0 8px; }
.block p { margin-bottom: 12px; color: #3a4652; }
.block ul, .block ol { padding-left: 22px; margin-bottom: 14px; }
.block li { margin-bottom: 8px; color: #3a4652; }
.block li::marker { color: var(--orange); font-weight: 700; }
.block strong { color: var(--navy); }

/* 提示框 */
.tip, .warn, .danger {
  border-radius: 10px;
  padding: 16px 18px 16px 16px;
  margin: 16px 0;
  font-size: 15px;
  display: flex;
  gap: 12px;
  align-items: flex-start;
}

.tip { background: #eef7ee; border: 1px solid #cde5cd; }
.warn { background: #fff7e6; border: 1px solid #f2ddb0; }
.danger { background: #fdeeec; border: 1px solid #f2c5c0; }

.tip .ico, .warn .ico, .danger .ico {
  flex: none;
  font-size: 18px;
  line-height: 1.5;
}

.tip strong { color: #2e7d32; }
.warn strong { color: #b26a00; }
.danger strong { color: #c0392b; }

/* ---------- 表格 ---------- */
.table-wrap { overflow-x: auto; margin: 16px 0; }

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14.5px;
  background: #fff;
}

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

th { background: var(--navy); color: #fff; font-weight: 600; white-space: nowrap; }
tr:nth-child(even) td { background: #f7f9fb; }

/* ---------- 数字统计条 ---------- */
.stats {
  background: #fff;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.stats .container {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  padding: 34px 20px;
}

.stat { text-align: center; }
.stat .num { font-size: 30px; font-weight: 800; color: var(--orange); }
.stat .num span { font-size: 16px; color: var(--muted); font-weight: 600; }
.stat .label { color: var(--muted); font-size: 14px; }

/* ---------- 步骤条 ---------- */
.steps { counter-reset: step; }

.step {
  position: relative;
  padding-left: 54px;
  margin-bottom: 22px;
}

.step::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: var(--navy);
  color: #fff;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

.step::after {
  content: "";
  position: absolute;
  left: 19px;
  top: 44px;
  bottom: -18px;
  width: 2px;
  background: var(--line);
}

.step:last-child::after { display: none; }
.step h4 { color: var(--navy); font-size: 16.5px; margin-bottom: 4px; }
.step p { color: var(--muted); font-size: 15px; }

/* ---------- 十不焊割 ---------- */
.rules { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }

.rule {
  background: #fff;
  border: 1px solid var(--line);
  border-left: 4px solid var(--orange);
  border-radius: 8px;
  padding: 13px 16px;
  font-size: 15px;
  display: flex;
  gap: 10px;
  align-items: flex-start;
}

.rule .no { font-weight: 800; color: var(--orange-dark); flex: none; }

/* ---------- 页脚 ---------- */
.site-footer {
  background: var(--navy);
  color: #9fb1c4;
  padding: 46px 0 0;
  margin-top: 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 34px;
}

.footer-grid h4 { color: #fff; font-size: 16px; margin-bottom: 14px; }
.footer-grid p { font-size: 14px; margin-bottom: 10px; }

.footer-grid a { color: #c3d1e0; font-size: 14px; display: block; margin-bottom: 9px; }
.footer-grid a:hover { color: var(--yellow); text-decoration: none; }

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, .12);
  padding: 18px 0;
  text-align: center;
  font-size: 13.5px;
  color: #7d90a5;
}

.footer-bottom a { color: #a9bccf; }
.footer-bottom a:hover { color: var(--yellow); }

.footer-bottom .divider { margin: 0 10px; opacity: .5; }

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .hero h1 { font-size: 32px; }
}

@media (max-width: 620px) {
  .grid-2, .grid-3, .grid-4, .rules { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .stats .container { grid-template-columns: repeat(2, 1fr); }
  .nav { flex-direction: column; height: auto; padding: 12px 0; }
  .nav-links { justify-content: center; }
  .hero { padding: 52px 0 44px; }
  .hero h1 { font-size: 27px; }
  .block { padding: 24px 20px; }
}