/* =========================================================
   致远钢结构 · 文章详情页
   同源设计系统：浅蓝 #2C4A7C + 金 #E8943A
   ========================================================= */
:root {
  --blue: #2C4A7C;
  --blue-deep: #1E3A66;
  --blue-footer: #142A4A;
  --blue-overlay: #23426F;
  --border: #5C7BA8;
  --gold: #E8943A;
  --cream: #F4EFE4;
  --ink: #18242F;
  --muted: #5C6B7E;
  --white: #ffffff;
  --radius-card: 12px;
  --radius-btn: 8px;
  --shadow-soft: 0 10px 30px rgba(20, 42, 74, 0.10);
  --pad-x: 80px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { font-family: system-ui, -apple-system, 'Segoe UI', 'Microsoft YaHei', system-ui, sans-serif; color: var(--ink); background: var(--white); line-height: 1.8; -webkit-font-smoothing: antialiased; }
a { text-decoration: none; color: inherit; }
.container { max-width: 1440px; margin: 0 auto; padding: 0 var(--pad-x); }

/* ===================== 顶部导航 ===================== */
.site-header { position: sticky; top: 0; z-index: 50; background: rgba(44,74,124,0.96); backdrop-filter: saturate(140%) blur(6px); border-bottom: 1px solid rgba(255,255,255,0.12); }
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 72px; }
.brand { display: flex; align-items: center; gap: 12px; color: var(--white); font-weight: 700; }
.brand-mark { width: 34px; height: 34px; border-radius: 8px; background: var(--gold); color: var(--blue-footer); display: grid; place-items: center; font-family: system-ui, -apple-system, 'Segoe UI', 'Microsoft YaHei', sans-serif; font-size: 22px; font-weight: 700; }
.brand-text { font-size: 19px; letter-spacing: .5px; }
.nav-links { display: flex; align-items: center; gap: 30px; }
.nav-links a { color: rgba(255,255,255,0.88); font-size: 15px; transition: color .2s; }
.nav-links a:hover { color: var(--gold); }
.nav-links a.active { color: var(--gold); font-weight: 500; }
.nav-cta { background: var(--gold); color: var(--blue-footer) !important; padding: 9px 18px; border-radius: var(--radius-btn); font-weight: 500; }
.nav-cta:hover { background: #F4C888; }
.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: 0; cursor: pointer; padding: 6px; }
.nav-toggle span { width: 24px; height: 2px; background: var(--white); border-radius: 2px; }

/* ===================== 标题区 ===================== */
.article-hero { background: linear-gradient(180deg, rgba(20,42,74,0.04), rgba(44,74,124,0.06)), radial-gradient(120% 100% at 80% 0%, rgba(232,148,58,0.12), transparent 55%); padding: 48px 0 40px; border-bottom: 1px solid rgba(92,123,168,0.18); }
.breadcrumb { display: flex; align-items: center; gap: 10px; font-size: 13px; color: var(--muted); margin-bottom: 20px; }
.breadcrumb a:hover { color: var(--gold); }
.breadcrumb .current { color: var(--blue); font-weight: 500; }
.kicker { font-family: system-ui, -apple-system, 'Segoe UI', 'Microsoft YaHei', sans-serif; letter-spacing: 3px; color: var(--gold); font-size: 17px; }
.kicker.light { color: var(--gold); }
.article-title { font-weight: 900; font-size: 42px; color: var(--blue-footer); margin: 6px 0 18px; line-height: 1.3; letter-spacing: .5px; max-width: 900px; }
.article-meta { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; color: var(--muted); font-size: 14px; }
.meta-author { display: flex; align-items: center; gap: 8px; color: var(--blue-deep); font-weight: 500; }
.avatar { width: 28px; height: 28px; border-radius: 50%; background: var(--gold); color: var(--blue-footer); display: grid; place-items: center; font-size: 13px; font-weight: 700; }
.avatar.lg { width: 48px; height: 48px; font-size: 18px; }
.dot { color: var(--border); }
.meta-tag { color: var(--gold); border: 1px solid rgba(232,148,58,0.5); background: rgba(232,148,58,0.10); padding: 3px 12px; border-radius: 999px; }

/* ===================== 主体网格 ===================== */
.article-body { padding: 48px 0 80px; }
.article-grid { display: grid; grid-template-columns: minmax(0,1fr) 300px; gap: 56px; align-items: start; }

/* 正文 */
.article-main { min-width: 0; }
.article-cover {
  height: 380px; border-radius: var(--radius-card); margin-bottom: 32px;
  background: linear-gradient(135deg, #23426F, #10203A);
  position: relative; overflow: hidden;
}
.article-cover::after { content: ""; position: absolute; inset: 0; background: radial-gradient(120% 120% at 80% 20%, rgba(232,148,58,0.25), transparent 55%); }
.lead { font-size: 18px; color: var(--ink); margin-bottom: 28px; }
.article-main h2 { font-size: 26px; color: var(--blue-footer); margin: 38px 0 16px; padding-left: 14px; border-left: 4px solid var(--gold); }
.article-main p { color: var(--muted); margin-bottom: 16px; }
.article-main strong { color: var(--blue-deep); }
.article-main ul, .article-main ol { margin: 0 0 18px 22px; color: var(--muted); }
.article-main li { margin-bottom: 8px; }
.article-main li strong { color: var(--blue-deep); }

/* 提示框 */
.callout { border-radius: var(--radius-card); padding: 18px 22px; margin: 22px 0; background: rgba(232,148,58,0.10); border: 1px solid rgba(232,148,58,0.4); }
.callout.tip .callout-label { display: inline-block; font-size: 12px; font-weight: 700; color: var(--blue-footer); background: var(--gold); padding: 2px 10px; border-radius: 999px; margin-bottom: 8px; }
.callout p { margin: 0; color: var(--blue-deep); }

/* 表格 */
.table-wrap { overflow-x: auto; margin: 20px 0 24px; border-radius: var(--radius-card); border: 1px solid rgba(92,123,168,0.25); }
.compare-table { width: 100%; border-collapse: collapse; font-size: 14px; min-width: 520px; }
.compare-table th { background: var(--blue); color: var(--white); text-align: left; padding: 12px 16px; font-weight: 500; }
.compare-table td { padding: 12px 16px; border-top: 1px solid rgba(92,123,168,0.18); color: var(--muted); }
.compare-table tbody tr:nth-child(even) { background: rgba(44,74,124,0.04); }
.compare-table td:first-child { color: var(--blue-deep); font-weight: 500; }

/* 引用 */
.pull-quote { margin: 26px 0; padding: 20px 26px; border-left: 4px solid var(--gold); background: rgba(44,74,124,0.05); font-size: 18px; color: var(--blue-footer); font-style: italic; border-radius: 0 var(--radius-card) var(--radius-card) 0; }

/* 作者卡 */
.author-card { display: flex; gap: 18px; align-items: center; margin: 36px 0 24px; padding: 22px; border: 1px solid rgba(92,123,168,0.25); border-radius: var(--radius-card); background: var(--cream); }
.author-card h4 { color: var(--blue-footer); font-size: 17px; margin-bottom: 4px; }
.author-card p { color: var(--muted); font-size: 14px; margin: 0; }

/* 标签 */
.article-tags { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 8px; }
.article-tags span { font-size: 13px; color: var(--blue-deep); background: rgba(44,74,124,0.08); padding: 5px 14px; border-radius: 999px; }

/* 右侧咨询卡 */
.article-aside { position: sticky; top: 96px; display: flex; flex-direction: column; gap: 20px; }
.aside-cta { border-radius: var(--radius-card); padding: 22px; background: var(--blue-overlay); color: var(--white); }
.aside-cta-title { font-size: 17px; font-weight: 700; margin-bottom: 6px; }
.aside-cta-sub { font-size: 13px; color: rgba(255,255,255,0.82); margin-bottom: 16px; }
.btn-primary { background: var(--gold); color: var(--blue-footer); padding: 14px 28px; border-radius: var(--radius-btn); font-weight: 500; transition: background .2s, transform .2s; display: inline-block; }
.btn-primary:hover { background: #F4C888; transform: translateY(-2px); }
.btn-primary.block { display: block; text-align: center; }

/* 相关文章 */
.related-title { font-size: 24px; color: var(--blue-footer); margin: 60px 0 22px; }
.related-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.related-card { border: 1px solid rgba(92,123,168,0.25); border-radius: var(--radius-card); overflow: hidden; background: var(--white); transition: box-shadow .2s, transform .2s; }
.related-card:hover { box-shadow: var(--shadow-soft); transform: translateY(-3px); }
.related-cover { height: 160px; background: linear-gradient(135deg, #23426F, #10203A); position: relative; }
.related-cover::after { content: ""; position: absolute; inset: 0; background: radial-gradient(120% 120% at 80% 20%, rgba(232,148,58,0.22), transparent 55%); }
.related-info { padding: 18px 20px 22px; }
.related-tag { font-size: 12px; color: var(--gold); border: 1px solid rgba(232,148,58,0.5); background: rgba(232,148,58,0.10); padding: 3px 10px; border-radius: 999px; }
.related-info h4 { font-size: 17px; color: var(--blue-footer); margin: 12px 0 8px; line-height: 1.4; }
.related-info p { font-size: 14px; color: var(--muted); margin: 0; }

/* ===================== CTA ===================== */
.article-body + .cta { background: var(--blue-overlay); color: var(--white); padding: 60px 0; }
.article-body + .cta .cta-inner { display: flex; align-items: center; justify-content: space-between; gap: 40px; flex-wrap: wrap; }
.article-body + .cta .cta-text h2 { font-size: 30px; font-weight: 700; margin: 6px 0 10px; }
.article-body + .cta .cta-text p { color: rgba(255,255,255,0.82); max-width: 540px; }
.article-body + .cta .cta-actions { display: flex; gap: 14px; flex-wrap: wrap; }
.btn-ghost { border: 1px solid rgba(255,255,255,0.5); color: var(--white); padding: 14px 28px; border-radius: var(--radius-btn); transition: background .2s; }
.btn-ghost:hover { background: rgba(255,255,255,0.12); }

/* ===================== 页脚 ===================== */
.site-footer { background: var(--blue-footer); color: rgba(255,255,255,0.85); padding: 56px 0 26px; }
.footer-inner { display: flex; justify-content: space-between; gap: 50px; flex-wrap: wrap; }
.footer-brand { max-width: 360px; }
.footer-brand p { margin-top: 16px; font-size: 14px; color: rgba(255,255,255,0.7); line-height: 1.8; }
.footer-cols { display: flex; gap: 70px; flex-wrap: wrap; }
.footer-col h4 { color: var(--white); font-size: 15px; margin-bottom: 16px; }
.footer-col a { display: block; font-size: 14px; color: rgba(255,255,255,0.72); margin-bottom: 10px; transition: color .2s; }
.footer-col a:hover { color: var(--gold); }
.footer-bottom { margin-top: 40px; padding-top: 22px; border-top: 1px solid rgba(255,255,255,0.12); display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; font-size: 13px; color: rgba(255,255,255,0.6); }

/* ===================== 返回顶部 ===================== */
.back-top { position: fixed; right: 26px; bottom: 26px; z-index: 40; width: 46px; height: 46px; border-radius: 50%; border: 0; cursor: pointer; background: var(--blue); color: var(--white); font-size: 20px; box-shadow: var(--shadow-soft); opacity: 0; pointer-events: none; transition: opacity .3s, background .2s; }
.back-top.show { opacity: 1; pointer-events: auto; }
.back-top:hover { background: var(--blue-deep); }

/* ===================== 响应式 ===================== */
@media (max-width: 1024px) {
  :root { --pad-x: 40px; }
  .article-grid { grid-template-columns: 1fr; gap: 36px; }
  .article-aside { position: static; flex-direction: row; flex-wrap: wrap; }
  .aside-cta { flex: 1 1 260px; }
  .article-title { font-size: 34px; }
}
@media (max-width: 768px) {
  :root { --pad-x: 20px; }
  .nav-links { position: absolute; top: 72px; left: 0; right: 0; flex-direction: column; align-items: flex-start; gap: 0; background: var(--blue-deep); padding: 8px 20px 18px; max-height: 0; overflow: hidden; transition: max-height .3s; }
  .nav-links.open { max-height: 340px; }
  .nav-links a { padding: 12px 0; width: 100%; }
  .nav-toggle { display: flex; }
  .article-title { font-size: 26px; }
  .article-cover { height: 220px; }
  .related-grid { grid-template-columns: 1fr; }
  .aside-cta { flex-basis: 100%; }
  .footer-bottom { flex-direction: column; gap: 8px; }
}