/* =============================================================================
   SEO 专题页共享样式 — 与主站 Route Navy 视觉一致，零 JS、系统字体、移动优先。
   ========================================================================== */

:root {
  --navy: #0d2b45;
  --navy-deep: #0a2033;
  --cream: #fffdf8;
  --sand: #f0e6c6;
  --sand-deep: #e2d7b7;
  --yellow: #f5b700;
  --yellow-bright: #f9d450;
  --gold: #c58600;
  --red: #c33a2d;
  --ink: #173a52;
  --ink-soft: #4b6677;
  --ink-faint: #6c7d84;
  --line: rgba(13, 43, 69, 0.15);
  --serif: "Noto Serif SC", "Songti SC", "STSong", Georgia, "Times New Roman", serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

* {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.9;
  color: var(--ink);
  background: var(--cream);
}

a {
  color: var(--navy);
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}

a:hover {
  color: var(--gold);
}

/* ---------- 顶栏 ---------- */

.site-header {
  background: var(--navy);
  color: #fff;
}

.site-header-inner {
  max-width: 980px;
  margin: 0 auto;
  padding: 14px 20px 10px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #fff;
  text-decoration: none;
}

.brand img {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  display: block;
}

.brand-name {
  font-family: var(--serif);
  font-size: 18px;
  font-weight: 900;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

.brand-sub {
  font-family: var(--mono);
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--yellow-bright);
  margin-left: auto;
  white-space: nowrap;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 16px;
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px solid rgba(255, 255, 255, 0.14);
  font-size: 13px;
  font-weight: 700;
}

.site-nav a {
  color: #bbcad0;
  text-decoration: none;
  padding: 2px 0;
}

.site-nav a:hover,
.site-nav a[aria-current="page"] {
  color: var(--yellow-bright);
}

/* ---------- 页首 ---------- */

.page-hero {
  background: linear-gradient(180deg, var(--sand) 0%, var(--cream) 100%);
  border-bottom: 1px solid var(--line);
}

.page-hero-inner {
  max-width: 780px;
  margin: 0 auto;
  padding: 28px 20px 30px;
}

.eyebrow {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--gold);
  margin: 0 0 10px;
}

.crumbs {
  font-size: 13px;
  color: var(--ink-faint);
  margin: 0 0 14px;
}

.crumbs a {
  color: var(--ink-soft);
}

h1 {
  font-family: var(--serif);
  font-size: 34px;
  font-weight: 900;
  line-height: 1.35;
  letter-spacing: -0.02em;
  margin: 0 0 14px;
}

.lede {
  font-size: 17px;
  color: var(--ink-soft);
  margin: 0 0 10px;
}

.meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  font-size: 13px;
  color: var(--ink-faint);
  margin-top: 14px;
}

/* ---------- 正文 ---------- */

.article {
  max-width: 780px;
  margin: 0 auto;
  padding: 30px 20px 10px;
}

.article h2 {
  font-family: var(--serif);
  font-size: 25px;
  font-weight: 900;
  line-height: 1.4;
  letter-spacing: -0.01em;
  margin: 44px 0 14px;
  padding-top: 10px;
}

.article h2 .sec-no {
  font-family: var(--mono);
  font-size: 13px;
  font-weight: 700;
  color: var(--gold);
  display: block;
  margin-bottom: 4px;
}

.article h3 {
  font-family: var(--serif);
  font-size: 19px;
  font-weight: 900;
  margin: 28px 0 10px;
}

.article p {
  margin: 0 0 16px;
}

.article ul,
.article ol {
  margin: 0 0 18px;
  padding-left: 1.4em;
}

.article li {
  margin-bottom: 8px;
}

.article li::marker {
  color: var(--gold);
  font-weight: 700;
}

.article strong {
  color: var(--navy);
}

.article table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
  margin: 0 0 20px;
}

.article th {
  text-align: left;
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #fff;
  background: var(--navy);
  padding: 10px 12px;
}

.article td {
  border-bottom: 1px solid var(--line);
  padding: 10px 12px;
  vertical-align: top;
}

.article tr:nth-child(even) td {
  background: rgba(240, 230, 198, 0.35);
}

.english-term {
  font-family: var(--mono);
  font-size: 0.92em;
  font-weight: 700;
  color: var(--navy);
  background: rgba(13, 43, 69, 0.06);
  border: 1px solid var(--line);
  border-radius: 5px;
  padding: 1px 7px;
  white-space: nowrap;
}

/* ---------- 提示块 ---------- */

.note,
.warn {
  border-radius: 12px;
  padding: 14px 18px;
  margin: 0 0 20px;
  font-size: 15px;
}

.note {
  background: rgba(13, 43, 69, 0.05);
  border: 1px solid var(--line);
}

.warn {
  background: #fff7ed;
  border: 1px solid rgba(195, 58, 45, 0.2);
}

.note .note-title,
.warn .note-title {
  display: block;
  font-weight: 900;
  margin-bottom: 4px;
  color: var(--navy);
}

.warn .note-title {
  color: var(--red);
}

/* ---------- 目录 ---------- */

.toc {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 18px 22px;
  margin: 0 0 8px;
}

.toc-title {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--gold);
  margin: 0 0 10px;
}

.toc ol {
  margin: 0;
  padding-left: 1.3em;
  font-size: 15px;
  font-weight: 700;
}

.toc li {
  margin-bottom: 6px;
}

.toc a {
  text-decoration: none;
}

/* ---------- FAQ ---------- */

.faq details {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fff;
  margin-bottom: 10px;
  overflow: hidden;
}

.faq summary {
  list-style: none;
  cursor: pointer;
  padding: 15px 18px;
  font-weight: 900;
  font-size: 16px;
  color: var(--navy);
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.faq summary::-webkit-details-marker {
  display: none;
}

.faq summary::before {
  content: "Q";
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 700;
  color: var(--gold);
  flex-shrink: 0;
}

.faq details[open] summary {
  border-bottom: 1px solid var(--line);
}

.faq .faq-answer {
  padding: 13px 18px 15px 18px;
  font-size: 15px;
  color: var(--ink-soft);
}

.faq .faq-answer p {
  margin: 0;
}

/* ---------- 相关阅读 ---------- */

.related {
  max-width: 780px;
  margin: 0 auto;
  padding: 10px 20px 0;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 12px;
  margin-top: 14px;
}

.related-card {
  display: block;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px 16px;
  text-decoration: none;
  transition: border-color 0.15s;
}

.related-card:hover {
  border-color: var(--navy);
  color: inherit;
}

.related-card .rc-tag {
  font-family: var(--mono);
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--gold);
}

.related-card .rc-title {
  display: block;
  font-weight: 900;
  font-size: 15px;
  margin-top: 4px;
  color: var(--navy);
}

.related-card .rc-desc {
  display: block;
  font-size: 13px;
  color: var(--ink-soft);
  margin-top: 4px;
  line-height: 1.7;
}

/* ---------- 行动卡 ---------- */

.cta {
  max-width: 780px;
  margin: 34px auto 0;
  padding: 0 20px;
}

.cta-box {
  background: var(--navy);
  color: #fff;
  border-radius: 16px;
  padding: 26px 26px 24px;
}

.cta-box .cta-eyebrow {
  font-family: var(--mono);
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--yellow-bright);
  margin: 0 0 8px;
}

.cta-box .cta-title {
  font-family: var(--serif);
  font-size: 22px;
  font-weight: 900;
  margin: 0 0 8px;
}

.cta-box p {
  font-size: 14px;
  color: #bbcad0;
  margin: 0 0 16px;
}

.cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.cta-actions a {
  border-radius: 999px;
  padding: 10px 20px;
  font-size: 14px;
  font-weight: 900;
  text-decoration: none;
}

.cta-primary {
  background: var(--yellow);
  color: var(--navy);
}

.cta-primary:hover {
  background: var(--yellow-bright);
  color: var(--navy);
}

.cta-secondary {
  background: transparent;
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.35);
}

.cta-secondary:hover {
  border-color: var(--yellow-bright);
  color: var(--yellow-bright);
}

/* ---------- 官方来源 / 页脚 ---------- */

.official {
  max-width: 780px;
  margin: 0 auto;
  padding: 30px 20px 0;
}

.official-box {
  border-top: 1px solid var(--line);
  padding-top: 18px;
  font-size: 14px;
  color: var(--ink-soft);
}

.official-box .pill {
  display: inline-block;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
  padding: 6px 14px;
  margin: 8px 8px 0 0;
  font-weight: 700;
  font-size: 13px;
  text-decoration: none;
}

.site-footer {
  margin-top: 40px;
  background: var(--navy);
  color: #bbcad0;
}

.site-footer-inner {
  max-width: 980px;
  margin: 0 auto;
  padding: 26px 20px 30px;
  font-size: 13px;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
  margin-bottom: 12px;
  font-weight: 700;
}

.footer-links a {
  color: #bbcad0;
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--yellow-bright);
}

.site-footer p {
  margin: 0;
  line-height: 1.8;
}

/* ---------- 响应式 ---------- */

@media (max-width: 640px) {
  body {
    font-size: 16px;
  }

  h1 {
    font-size: 27px;
  }

  .article h2 {
    font-size: 21px;
  }

  .brand-sub {
    display: none;
  }

  .site-nav {
    font-size: 12px;
    gap: 4px 12px;
  }

  .article table {
    display: block;
    overflow-x: auto;
  }

  .cta-box {
    padding: 20px;
  }
}