/* ============================================================
   伟德指南 / 共享样式 site.css
   目录型内容地图 · 墨蓝 + 纸张米白 + 暖金索引色
   ============================================================ */

/* ---------- 1. reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body { margin: 0; }

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd { margin: 0; }

ul, ol { margin: 0; padding: 0; list-style: none; }

img, svg, video { display: block; max-width: 100%; height: auto; }

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
}

a { color: inherit; }

table { border-collapse: collapse; width: 100%; }

/* ---------- 2. 变量 ---------- */
:root {
  --ink-900: #0E1A2B;
  --ink-700: #1B2E4A;
  --ink-500: #2F4A6E;
  --paper-100: #F7F3EA;
  --paper-200: #EDE6D6;
  --gold-500: #C8963E;
  --gold-300: #E3C48A;
  --signal: #E2571F;
  --signal-dark: #C2461A;
  --verify: #2E7D5B;
  --slate: #64748B;
  --white: #FFFFFF;

  --font-heading: "Noto Sans SC Condensed", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", Georgia, serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --wrap: 1200px;
  --pad: clamp(16px, 4vw, 40px);
  --measure: 40em;
  --radius: 8px;
  --header-offset: 112px;
  --line: 1px solid rgba(47, 74, 110, 0.22);
  --shadow: 0 1px 0 rgba(14, 26, 43, 0.05), 0 14px 34px -26px rgba(14, 26, 43, 0.55);
}

/* ---------- 3. 基础排版 ---------- */
body {
  background-color: var(--paper-100);
  background-image: repeating-linear-gradient(0deg, rgba(14, 26, 43, 0.016) 0 1px, transparent 1px 4px);
  color: var(--ink-900);
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 1.85;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.15;
  color: var(--ink-900);
}

h1 { font-size: clamp(2.4rem, 6vw, 5rem); line-height: 1.04; }
h2 { font-size: clamp(1.55rem, 3.4vw, 2.4rem); }
h3 { font-size: clamp(1.15rem, 1.8vw, 1.35rem); font-weight: 800; }
h4 { font-size: 1.05rem; font-weight: 800; }

p { max-width: 68em; }

a { text-decoration: none; }

:focus-visible {
  outline: 2px solid var(--gold-500);
  outline-offset: 3px;
  border-radius: 2px;
}

::selection { background: var(--gold-300); color: var(--ink-900); }

#main-content {
  display: block;
  scroll-margin-top: 130px;
}

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--pad);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  left: var(--pad);
  top: -120px;
  z-index: 200;
  padding: 10px 18px;
  background: var(--gold-500);
  color: var(--ink-900);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 14px;
  border-radius: 0 0 6px 6px;
  transition: top 0.18s ease;
}

.skip-link:focus { top: 0; }

/* ---------- 4. 页头 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: var(--ink-900);
  color: var(--paper-100);
  border-bottom: 1px solid rgba(200, 150, 62, 0.38);
}

.masthead {
  height: 34px;
  overflow: hidden;
  background: var(--ink-700);
  border-bottom: 1px solid rgba(200, 150, 62, 0.22);
  transition: height 0.22s ease, opacity 0.22s ease;
}

.masthead__inner {
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--pad);
  height: 34px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.masthead__left,
.masthead__right {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0;
  max-width: none;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: rgba(247, 243, 234, 0.6);
  white-space: nowrap;
}

.masthead__code {
  color: var(--gold-300);
  border: 1px solid rgba(200, 150, 62, 0.42);
  border-radius: 3px;
  padding: 1px 7px;
}

.masthead__sep { color: rgba(200, 150, 62, 0.65); }

.site-header.is-condensed .masthead {
  height: 0;
  opacity: 0;
  border-bottom-color: transparent;
}

.header-main__inner {
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 14px var(--pad);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: clamp(12px, 2vw, 32px);
  transition: padding 0.22s ease;
}

.site-header.is-condensed .header-main__inner { padding-block: 7px; }

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
}

.brand__mark {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border: 1px solid rgba(200, 150, 62, 0.55);
  border-radius: 6px;
  background: var(--ink-700);
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: 0.04em;
  color: var(--gold-300);
  transition: background-color 0.16s ease, border-color 0.16s ease;
}

.brand:hover .brand__mark,
.brand:focus-visible .brand__mark {
  background: var(--ink-500);
  border-color: var(--gold-500);
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.25;
}

.brand__name {
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: 1.15rem;
  letter-spacing: 0.02em;
  color: var(--paper-100);
}

.brand__tagline {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 11.5px;
  color: var(--gold-300);
  opacity: 0.85;
  transition: opacity 0.2s ease;
}

.site-header.is-condensed .brand__tagline { opacity: 0; }

.nav-zone {
  display: flex;
  align-items: center;
  gap: clamp(8px, 1.4vw, 18px);
}

.site-nav { position: relative; }

.site-nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
}

.site-nav__link {
  display: inline-block;
  padding: 8px 12px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 14.5px;
  letter-spacing: 0.01em;
  color: rgba(247, 243, 234, 0.82);
  border-bottom: 2px solid transparent;
  transition: color 0.16s ease, border-color 0.16s ease;
}

.site-nav__link:hover {
  color: var(--white);
  border-bottom-color: var(--gold-300);
}

.site-nav__link[aria-current="page"] {
  color: var(--gold-300);
  border-bottom-color: var(--gold-500);
}

.version-badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 5px 10px;
  border: 1px dashed rgba(200, 150, 62, 0.5);
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: var(--gold-300);
  white-space: nowrap;
}

.version-badge__dot {
  width: 7px;
  height: 7px;
  border-radius: 2px;
  background: var(--signal);
}

.header-cta {
  display: inline-flex;
  align-items: center;
  padding: 9px 15px;
  border-radius: 4px;
  background: var(--gold-500);
  color: var(--ink-900);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 13.5px;
  letter-spacing: 0.02em;
  white-space: nowrap;
  transition: background-color 0.16s ease, color 0.16s ease;
}

.header-cta:hover { background: var(--gold-300); }

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(200, 150, 62, 0.45);
  border-radius: 6px;
  color: var(--paper-100);
  transition: border-color 0.16s ease, background-color 0.16s ease;
}

.nav-toggle:hover { border-color: var(--gold-500); }

.nav-toggle__bars {
  display: flex;
  flex-direction: column;
  gap: 5px;
  width: 20px;
}

.nav-toggle__bar {
  display: block;
  height: 2px;
  background: currentColor;
  transition: transform 0.22s ease;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:first-child { transform: translateY(3.5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:last-child { transform: translateY(-3.5px) rotate(-45deg); }

.site-progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 100%;
  height: 2px;
  background: var(--signal);
  transform: scaleX(0);
  transform-origin: 0 50%;
  will-change: transform;
}

/* ---------- 5. 页脚 ---------- */
.site-footer {
  background: var(--ink-900);
  color: rgba(247, 243, 234, 0.76);
  font-family: var(--font-serif);
  font-size: 14.5px;
  line-height: 1.8;
}

.footer-ruler {
  height: 14px;
  background-image: repeating-linear-gradient(90deg, rgba(200, 150, 62, 0.55) 0 1px, transparent 1px 26px);
  background-size: 26px 7px;
  background-position: 0 bottom;
  background-repeat: repeat-x;
  border-bottom: 1px solid rgba(200, 150, 62, 0.3);
}

.footer-main__inner {
  display: grid;
  grid-template-columns: minmax(0, 4fr) minmax(0, 8fr);
  gap: clamp(24px, 4vw, 56px);
  padding-block: clamp(34px, 5vw, 58px);
}

.footer-brand__name {
  max-width: none;
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: 1.6rem;
  letter-spacing: -0.01em;
  color: var(--paper-100);
}

.footer-brand__closing {
  max-width: 24em;
  margin-top: 10px;
  font-style: italic;
  font-size: 15px;
  color: var(--gold-300);
}

.footer-brand__meta {
  max-width: none;
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: rgba(247, 243, 234, 0.5);
}

.footer-nav {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(16px, 2vw, 32px);
}

.footer-col__title {
  max-width: none;
  padding-bottom: 10px;
  margin-bottom: 12px;
  border-bottom: 1px solid rgba(200, 150, 62, 0.22);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--gold-300);
}

.footer-col__item { margin-bottom: 8px; }

.footer-link {
  color: rgba(247, 243, 234, 0.76);
  border-bottom: 1px solid transparent;
  transition: color 0.16s ease, border-color 0.16s ease;
}

.footer-link:hover {
  color: var(--gold-300);
  border-bottom-color: var(--gold-500);
}

.footer-contact { border-top: 1px solid rgba(200, 150, 62, 0.22); }

.footer-contact__inner {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(16px, 3vw, 36px);
  padding-block: clamp(22px, 3.4vw, 34px);
}

.footer-contact__label {
  max-width: none;
  margin-bottom: 4px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--gold-300);
}

.footer-contact__value {
  max-width: none;
  font-family: var(--font-mono);
  font-size: 14.5px;
  letter-spacing: 0.02em;
  color: var(--paper-100);
  word-break: break-word;
}

.footer-contact__note {
  grid-column: 1 / -1;
  max-width: var(--measure);
  padding-top: 16px;
  border-top: 1px dashed rgba(247, 243, 234, 0.14);
  font-size: 13.5px;
  color: rgba(247, 243, 234, 0.6);
}

.footer-legal {
  background: rgba(0, 0, 0, 0.28);
  border-top: 1px solid rgba(200, 150, 62, 0.18);
}

.footer-legal__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 24px;
  padding-block: 16px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: rgba(247, 243, 234, 0.55);
}

.footer-legal__icp,
.footer-legal__copy { max-width: none; }

/* ---------- 6. 章节骨架 ---------- */
.section { padding-block: clamp(40px, 6vw, 84px); }
.section--tight { padding-block: clamp(26px, 4vw, 52px); }

.section__head {
  display: flex;
  flex-direction: column;
  gap: 10px;
  max-width: var(--measure);
  margin-bottom: clamp(20px, 3vw, 36px);
}

.section__eyebrow {
  display: flex;
  align-items: center;
  gap: 8px;
  max-width: none;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--gold-500);
}

.section__eyebrow::before {
  content: "";
  width: 22px;
  height: 2px;
  background: var(--gold-500);
}

.section__title { color: var(--ink-900); }

.section__lead {
  max-width: var(--measure);
  font-size: 16px;
  color: var(--ink-500);
}

/* ---------- 7. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 20px;
  border: 1px solid transparent;
  border-radius: 4px;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 14.5px;
  letter-spacing: 0.02em;
  cursor: pointer;
  transition: background-color 0.16s ease, border-color 0.16s ease, color 0.16s ease;
}

.btn--primary {
  background: var(--signal);
  border-color: var(--signal);
  color: var(--white);
}

.btn--primary:hover {
  background: var(--signal-dark);
  border-color: var(--signal-dark);
}

.btn--gold {
  background: var(--gold-500);
  border-color: var(--gold-500);
  color: var(--ink-900);
}

.btn--gold:hover {
  background: var(--gold-300);
  border-color: var(--gold-300);
}

.btn--ghost {
  background: transparent;
  border-color: rgba(47, 74, 110, 0.4);
  color: var(--ink-900);
}

.btn--ghost:hover {
  border-color: var(--gold-500);
  color: var(--ink-700);
}

.btn--quiet {
  padding-inline: 0;
  background: transparent;
  color: var(--ink-500);
  text-decoration: underline;
  text-decoration-color: var(--gold-300);
  text-underline-offset: 4px;
}

.btn--quiet:hover {
  color: var(--ink-900);
  text-decoration-color: var(--gold-500);
}

/* ---------- 8. 面包屑 ---------- */
.breadcrumb { padding-block: 14px; }

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: var(--slate);
}

.breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.breadcrumb__link {
  color: var(--ink-500);
  border-bottom: 1px solid transparent;
  transition: color 0.16s ease, border-color 0.16s ease;
}

.breadcrumb__link:hover {
  color: var(--ink-900);
  border-bottom-color: var(--gold-500);
}

.breadcrumb__sep { color: var(--gold-500); }

/* ---------- 9. 长文 ---------- */
.prose {
  max-width: var(--measure);
  font-size: 17px;
  line-height: 1.9;
  color: var(--ink-900);
}

.prose h2 { margin-top: 1.9em; margin-bottom: 0.6em; }
.prose h3 { margin-top: 1.6em; margin-bottom: 0.5em; }
.prose p { max-width: none; margin-bottom: 1.1em; }

.prose ul,
.prose ol {
  margin-bottom: 1.1em;
  padding-left: 1.3em;
}

.prose ul { list-style: square; }
.prose ol { list-style: decimal; }

.prose li { margin-bottom: 0.4em; }

.prose a {
  text-decoration: underline;
  text-decoration-color: var(--gold-300);
  text-underline-offset: 4px;
  transition: text-decoration-color 0.16s ease, color 0.16s ease;
}

.prose a:hover {
  text-decoration-color: var(--gold-500);
  color: var(--ink-700);
}

.prose strong { font-weight: 700; }

.prose__card {
  padding: clamp(16px, 2.4vw, 26px);
  background: var(--paper-200);
  border: 1px solid rgba(47, 74, 110, 0.18);
  border-radius: var(--radius);
  margin-bottom: 1.4em;
}

/* ---------- 10. 网格 ---------- */
.grid { display: grid; gap: clamp(16px, 2.4vw, 32px); }

.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--5-7 { grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); }
.grid--3-8 { grid-template-columns: minmax(0, 3fr) minmax(0, 8fr); }

/* ---------- 11. 卡片与编号 ---------- */
.card {
  position: relative;
  display: block;
  padding: clamp(18px, 2.4vw, 28px);
  background: var(--white);
  border: 1px solid rgba(47, 74, 110, 0.22);
  border-radius: var(--radius);
  color: inherit;
  transition: border-color 0.16s ease, box-shadow 0.16s ease, background-color 0.16s ease;
}

.card:hover {
  border-color: var(--gold-500);
  box-shadow: var(--shadow);
}

.card__num {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--gold-500);
}

.card__title {
  margin-bottom: 8px;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.15rem;
  line-height: 1.35;
  letter-spacing: -0.01em;
}

.card__body {
  max-width: none;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-500);
}

.card__foot {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px dashed rgba(47, 74, 110, 0.24);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: var(--slate);
}

.num {
  font-family: var(--font-mono);
  font-size: 0.92em;
  letter-spacing: 0.04em;
  color: var(--gold-500);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  border: 1px solid rgba(47, 74, 110, 0.3);
  border-radius: 999px;
  background: var(--paper-200);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--ink-500);
}

.tag--verify {
  color: var(--verify);
  border-color: rgba(46, 125, 91, 0.45);
  background: rgba(46, 125, 91, 0.08);
}

.tag--signal {
  color: var(--signal);
  border-color: rgba(226, 87, 31, 0.45);
  background: rgba(226, 87, 31, 0.08);
}

/* ---------- 12. 索引栏 ---------- */
.index-rail {
  position: sticky;
  top: var(--header-offset);
  padding: 18px;
  background: var(--ink-700);
  border-radius: var(--radius);
  color: rgba(247, 243, 234, 0.8);
  font-size: 14px;
}

.index-rail__head {
  max-width: none;
  margin-bottom: 10px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(200, 150, 62, 0.3);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--gold-300);
}

.index-rail__list {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.index-rail__link {
  display: flex;
  gap: 10px;
  padding: 7px 10px;
  border-left: 3px solid transparent;
  color: inherit;
  line-height: 1.6;
  transition: border-color 0.16s ease, background-color 0.16s ease, color 0.16s ease;
}

.index-rail__link:hover {
  background: rgba(200, 150, 62, 0.08);
  color: var(--paper-100);
}

.index-rail__link.is-active,
.index-rail__link[aria-current="true"] {
  border-left-color: var(--gold-500);
  background: rgba(200, 150, 62, 0.1);
  color: var(--gold-300);
}

.index-rail__num {
  flex: 0 0 auto;
  padding-top: 2px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: var(--gold-500);
}

/* ---------- 13. 版本 Tab ---------- */
.tabs__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 20px;
}

.tabs__tab {
  padding: 9px 18px;
  border: 1px solid rgba(47, 74, 110, 0.3);
  border-radius: 4px;
  background: var(--white);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 14px;
  color: var(--ink-500);
  transition: background-color 0.16s ease, border-color 0.16s ease, color 0.16s ease;
}

.tabs__tab:hover {
  border-color: var(--gold-500);
  color: var(--ink-900);
}

.tabs__tab[aria-selected="true"] {
  background: var(--ink-700);
  border-color: var(--ink-700);
  color: var(--paper-100);
}

.tabs__tab[aria-selected="true"]:hover { color: var(--paper-100); }

.tabs__panel[hidden] { display: none; }

/* ---------- 14. 复制编号 ---------- */
.copy-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px;
  border: 1px dashed rgba(200, 150, 62, 0.6);
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--gold-500);
  transition: background-color 0.16s ease, border-color 0.16s ease, color 0.16s ease;
}

.copy-btn:hover {
  background: rgba(200, 150, 62, 0.12);
  border-color: var(--gold-500);
}

.copy-btn.is-copied {
  background: var(--verify);
  border-color: var(--verify);
  border-style: solid;
  color: var(--white);
}

/* ---------- 15. 筛选标签 ---------- */
.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chip {
  padding: 6px 14px;
  border: 1px solid rgba(47, 74, 110, 0.28);
  border-radius: 999px;
  background: var(--paper-100);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: var(--ink-500);
  transition: background-color 0.16s ease, border-color 0.16s ease, color 0.16s ease;
}

.chip:hover {
  border-color: var(--gold-500);
  color: var(--ink-900);
}

.chip[aria-pressed="true"] {
  background: var(--ink-700);
  border-color: var(--ink-700);
  color: var(--paper-100);
}

/* ---------- 16. 两版对照 ---------- */
.compare {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(12px, 2vw, 24px);
}

.compare__col {
  overflow: hidden;
  background: var(--white);
  border: 1px solid rgba(47, 74, 110, 0.22);
  border-radius: var(--radius);
}

.compare__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 14px 18px;
  background: var(--ink-700);
  color: var(--paper-100);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.04em;
}

.compare__row {
  display: grid;
  grid-template-columns: 82px minmax(0, 1fr);
  gap: 12px;
  padding: 12px 18px;
  border-top: 1px solid rgba(47, 74, 110, 0.14);
  font-size: 14.5px;
  transition: background-color 0.16s ease, box-shadow 0.16s ease;
}

.compare__row:first-of-type { border-top: 0; }

.compare__row:hover { background: var(--paper-200); }

.compare__row.is-diff {
  background: rgba(226, 87, 31, 0.06);
  box-shadow: inset 3px 0 0 var(--signal);
}

.compare__key {
  max-width: none;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: var(--slate);
}

.compare__val {
  max-width: none;
  color: var(--ink-900);
}

.compare__row.is-diff .compare__val { font-weight: 600; }

/* ---------- 17. 图像容器 ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  background: var(--paper-200);
  border: 1px solid rgba(47, 74, 110, 0.24);
  border-radius: var(--radius);
}

.media-frame__inner {
  position: relative;
  aspect-ratio: 16 / 10;
  display: grid;
  place-items: center;
  background-color: var(--paper-200);
  background-image: repeating-linear-gradient(135deg, rgba(47, 74, 110, 0.08) 0 1px, transparent 1px 14px);
}

.media-frame__inner::after {
  content: "";
  position: absolute;
  inset: 12px;
  border: 1px dashed rgba(47, 74, 110, 0.28);
  border-radius: 4px;
  pointer-events: none;
}

.media-frame__inner img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame--wide .media-frame__inner { aspect-ratio: 21 / 9; }
.media-frame--tall .media-frame__inner { aspect-ratio: 4 / 5; }
.media-frame--square .media-frame__inner { aspect-ratio: 1 / 1; }

.media-frame__cap {
  display: flex;
  align-items: baseline;
  gap: 10px;
  max-width: none;
  padding: 12px 16px 0;
  font-style: italic;
  font-size: 13.5px;
  color: var(--slate);
}

.media-frame__cap::before {
  content: attr(data-cap-num);
  font-family: var(--font-mono);
  font-style: normal;
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--gold-500);
}

/* ---------- 18. 折叠块 ---------- */
.fold {
  overflow: hidden;
  background: var(--white);
  border: 1px solid rgba(47, 74, 110, 0.22);
  border-radius: var(--radius);
  transition: border-color 0.16s ease, box-shadow 0.16s ease;
}

.fold + .fold { margin-top: 10px; }

.fold[open] {
  border-left: 3px solid var(--gold-500);
  box-shadow: var(--shadow);
}

.fold__summary {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 20px;
  cursor: pointer;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 15.5px;
  color: var(--ink-900);
  transition: background-color 0.16s ease;
}

.fold__summary::-webkit-details-marker { display: none; }
.fold__summary::marker { content: ""; }
.fold__summary:hover { background: var(--paper-200); }
.fold[open] .fold__summary {
  background: var(--paper-100);
  border-bottom: 1px solid rgba(47, 74, 110, 0.16);
}

.fold__body {
  padding: 16px 20px 20px;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--ink-900);
}

.fold__body p { max-width: none; margin-bottom: 0.9em; }
.fold__body p:last-child { margin-bottom: 0; }

/* ---------- 19. 时间轴 ---------- */
.timeline {
  padding-left: 24px;
  border-left: 2px solid rgba(200, 150, 62, 0.4);
}

.timeline__item {
  position: relative;
  padding-bottom: 28px;
}

.timeline__item:last-child { padding-bottom: 0; }

.timeline__mark {
  position: absolute;
  left: -31px;
  top: 6px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--paper-100);
  border: 2px solid var(--gold-500);
}

.timeline__item--current .timeline__mark {
  background: var(--signal);
  border-color: var(--signal);
}

.timeline__body {
  max-width: var(--measure);
  font-size: 15.5px;
}

/* ---------- 20. 响应式 ---------- */
@media (max-width: 1100px) {
  :root { --header-offset: 96px; }
}

@media (max-width: 980px) {
  :root { --header-offset: 80px; }

  .masthead { display: none; }

  .nav-toggle { display: inline-flex; }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    max-height: 0;
    overflow: hidden;
    background: var(--ink-900);
    border-top: 1px solid rgba(200, 150, 62, 0.25);
    border-bottom: 1px solid rgba(200, 150, 62, 0.38);
    transition: max-height 0.22s ease;
  }

  .site-nav[data-open="true"] {
    max-height: 80vh;
    overflow-y: auto;
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    max-width: var(--wrap);
    margin-inline: auto;
    padding: 6px var(--pad) 18px;
  }

  .site-nav__item { border-bottom: 1px solid rgba(247, 243, 234, 0.1); }
  .site-nav__item:last-child { border-bottom: 0; }

  .site-nav__link {
    display: block;
    padding: 14px 12px;
    font-size: 16px;
    border-bottom: 0;
    border-left: 3px solid transparent;
  }

  .site-nav__link:hover {
    border-bottom-color: transparent;
    background: rgba(200, 150, 62, 0.06);
  }

  .site-nav__link[aria-current="page"] {
    border-left-color: var(--gold-500);
    border-bottom-color: transparent;
    background: rgba(200, 150, 62, 0.09);
  }

  .footer-main__inner { grid-template-columns: minmax(0, 1fr); }
  .footer-nav { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-contact__inner { grid-template-columns: repeat(2, minmax(0, 1fr)); }

  .grid--2,
  .grid--3,
  .grid--5-7,
  .grid--3-8 { grid-template-columns: minmax(0, 1fr); }

  .compare { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 720px) {
  .version-badge { display: none; }
  .brand__tagline { display: none; }
  .header-cta { padding: 8px 12px; font-size: 12.5px; }
  .footer-legal__inner { justify-content: flex-start; }
}

@media (max-width: 560px) {
  .footer-nav { grid-template-columns: minmax(0, 1fr); }
  .footer-contact__inner { grid-template-columns: minmax(0, 1fr); }
  .compare__row { grid-template-columns: minmax(0, 1fr); gap: 4px; }
}

/* ---------- 21. 动效克制 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    transition-duration: 0.001ms !important;
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
  }

  .site-progress { transition: none !important; }
}