:root {
  --color-surface: #fefefe;
  --color-surface-alt: #f5f5f5;
  --color-surface-deep: #e8e9e9;
  --color-ink: #484c51;
  --color-ink-soft: #6d7279;
  --color-ink-muted: #7a7f85;
  --color-line: #dddedf;
  --color-primary: #3c78bd;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #e3ebf5;
  --color-accent: #da2547;
  --color-accent-ink: #ffffff;
  --color-highlight: #f8d7dd;
  --color-focus: #e2183d;
  --color-contrast-surface: #0f1318;
  --color-contrast-ink: #e4e5e7;
  --color-contrast-line: #3e4146;
  --color-contrast-accent: #df4460;
  --overlay-scrim: linear-gradient(180deg, rgba(15, 19, 24, 0.35) 0%, rgba(15, 19, 24, 0.72) 55%, rgba(15, 19, 24, 0.92) 100%);
  --font-heading: "Songti SC", "Source Han Serif SC", "Noto Serif SC", SimSun, serif;
  --font-body: "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, Menlo, Consolas, monospace;
  --text-xs: 11.4px;
  --text-sm: 14.3px;
  --text-base: 16px;
  --text-lg: 20.0px;
  --text-xl: 25.0px;
  --text-2xl: 31.2px;
  --text-3xl: 39.1px;
  --text-4xl: 48.8px;
  --text-display: clamp(34px, 4.2vw, 54px);
  --text-figure: clamp(28px, 3.0vw, 39px);
  --weight-heading: 646;
  --weight-body: 400;
  --leading-body: 1.86;
  --leading-heading: 1.18;
  --tracking-heading: 0.001em;
  --radius-sm: 2px;
  --radius-md: 2px;
  --radius-lg: 2px;
  --radius-pill: 2px;
  --border-thin: 1px;
  --border-thick: 3px;
  --shadow-1: none;
  --shadow-2: none;
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1100px;
  --measure: 65ch;
  --gutter: 24px;
  --section-y: 87px;
  --section-y-lg: 122px;
}

/* ============================================================
   01 · RESET
   ============================================================ */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-padding-top: 112px;
}

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

body {
  margin: 0;
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

p { margin: 0 0 var(--space-2); }
p:last-child { margin-bottom: 0; }

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

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

a {
  color: var(--color-primary);
  text-decoration: none;
  text-underline-offset: 3px;
}

a:hover { text-decoration: underline; }

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

table {
  border-collapse: collapse;
  border-spacing: 0;
}

hr {
  border: 0;
  border-top: var(--border-thin) solid var(--color-line);
  margin: var(--space-4) 0;
}

dl, dd, dt { margin: 0; }

::selection {
  background-color: var(--color-highlight);
  color: var(--color-ink);
}

:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

.section--deep :focus-visible,
.footer-tier--legal :focus-visible,
.figure__overlay :focus-visible {
  outline-color: var(--color-contrast-accent);
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ============================================================
   02 · 排版基元
   ============================================================ */
.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding-left: var(--gutter);
  padding-right: var(--gutter);
}

.prose {
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
}

.prose p + p { margin-top: var(--space-2); }

.lead {
  font-size: var(--text-lg);
  line-height: 1.7;
  color: var(--color-ink);
}

.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-primary);
  border-bottom: var(--border-thin) solid var(--color-line);
  padding-bottom: 4px;
  margin-bottom: var(--space-2);
}

.display-title {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: -0.01em;
  color: var(--color-ink);
}

.figure-value {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 600;
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--color-primary);
}

.figure-value--accent { color: var(--color-accent); }

.tnum { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }

.text-soft { color: var(--color-ink-soft); }
.text-muted { color: var(--color-ink-muted); font-size: var(--text-sm); }

.rule {
  display: block;
  width: 100%;
  height: 0;
  border-top: var(--border-thin) solid var(--color-line);
}

.rule--accent { border-top: var(--border-thick) solid var(--color-accent); }

/* ============================================================
   03 · 内联强调
   ============================================================ */
.mark {
  background: none;
  color: inherit;
  border-bottom: 2px solid var(--color-accent);
  padding-bottom: 1px;
}

.mark--sub,
.mark--foreign {
  background-color: var(--color-highlight);
  border-bottom: 2px solid var(--color-accent);
  color: color-mix(in srgb, var(--color-accent) 72%, var(--color-contrast-surface));
  padding: 1px 4px;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  line-height: 1.5;
  padding: 1px 7px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  color: var(--color-ink-soft);
  background-color: var(--color-surface);
  white-space: nowrap;
}

.tag--sub,
.tag--foreign {
  background-color: var(--color-highlight);
  border-color: var(--color-accent);
  color: color-mix(in srgb, var(--color-accent) 72%, var(--color-contrast-surface));
}

.tag--round {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background-color: var(--color-primary-soft);
}

/* ============================================================
   04 · 按钮
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: 10px 18px;
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1.4;
  letter-spacing: 0.04em;
  border-radius: var(--radius-sm);
  border: var(--border-thin) solid var(--color-primary);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.16s ease-out, color 0.16s ease-out, border-color 0.16s ease-out;
}

.btn:hover {
  background-color: color-mix(in srgb, var(--color-primary) 84%, var(--color-contrast-surface));
  border-color: color-mix(in srgb, var(--color-primary) 84%, var(--color-contrast-surface));
  color: var(--color-primary-ink);
  text-decoration: none;
}

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

.btn--ghost {
  background-color: transparent;
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn--ghost:hover {
  background-color: var(--color-primary-soft);
  color: var(--color-primary);
}

.btn--accent {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}

.btn--accent:hover {
  background-color: color-mix(in srgb, var(--color-accent) 84%, var(--color-contrast-surface));
  border-color: color-mix(in srgb, var(--color-accent) 84%, var(--color-contrast-surface));
}

.btn--sm { padding: 6px 12px; font-size: var(--text-xs); }

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  align-items: center;
}

/* ============================================================
   05 · SKIP LINK
   ============================================================ */
.skip-link {
  position: absolute;
  left: var(--space-2);
  top: -80px;
  z-index: 200;
  display: inline-block;
  padding: 10px 18px;
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  font-weight: 600;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: top 0.16s ease-out;
}

.skip-link:focus {
  top: var(--space-2);
  text-decoration: none;
}

/* ============================================================
   06 · 头部
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background-color: var(--color-surface);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.header-status {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-bottom: var(--border-thin) solid var(--color-contrast-line);
}

.header-status__inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 7px var(--gutter);
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-xs);
  line-height: 1.5;
  letter-spacing: 0.05em;
  transition: padding 0.16s ease-out;
}

.header-status__label {
  font-family: var(--font-mono);
  letter-spacing: 0.1em;
  color: var(--color-contrast-accent);
  border: var(--border-thin) solid var(--color-contrast-line);
  border-radius: var(--radius-sm);
  padding: 1px 6px;
  white-space: nowrap;
}

.header-status__text {
  flex: 1 1 auto;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  color: var(--color-contrast-ink);
}

.header-status__icp {
  font-family: var(--font-mono);
  color: color-mix(in srgb, var(--color-contrast-ink) 62%, var(--color-contrast-surface));
  white-space: nowrap;
}

.site-header[data-scrolled="true"] .header-status__inner { padding-top: 3px; padding-bottom: 3px; }
.site-header[data-scrolled="true"] .header-status__text { color: color-mix(in srgb, var(--color-contrast-ink) 76%, var(--color-contrast-surface)); }

.header-bar { background-color: var(--color-surface); }

.header-bar__inner {
  position: relative;
  max-width: var(--container);
  margin: 0 auto;
  padding: 10px var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--color-ink);
  flex: 0 0 auto;
}

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

.brand__mark {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.1em;
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  padding: 7px 8px;
  border-radius: var(--radius-sm);
  line-height: 1;
}

.brand__text {
  display: flex;
  flex-direction: column;
  gap: 1px;
  line-height: 1.25;
}

.brand__name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
  letter-spacing: 0.02em;
}

.brand__line {
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  letter-spacing: 0.06em;
}

.site-nav { flex: 0 1 auto; }

.site-nav__list {
  display: flex;
  align-items: stretch;
  flex-wrap: nowrap;
}

.site-nav__item { display: flex; }

.site-nav__item + .site-nav__item { border-left: var(--border-thin) solid var(--color-line); }

.site-nav__list a {
  display: flex;
  align-items: center;
  padding: 9px 13px;
  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--color-ink-soft);
  text-decoration: none;
  border-left: var(--border-thick) solid transparent;
  transition: color 0.16s ease-out, background-color 0.16s ease-out, border-left-color 0.16s ease-out;
}

.site-nav__list a:hover {
  color: var(--color-ink);
  background-color: var(--color-surface-alt);
  border-left-color: color-mix(in srgb, var(--color-primary) 45%, var(--color-surface));
  text-decoration: none;
}

.site-nav__list a[aria-current="page"] {
  color: var(--color-primary);
  background-color: var(--color-primary-soft);
  border-left-color: var(--color-primary);
  font-weight: 600;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.04em;
}

.nav-toggle:hover { background-color: var(--color-surface-alt); }

.nav-toggle__bars {
  display: block;
  width: 16px;
  height: 10px;
  background-image: linear-gradient(
    var(--color-primary) 0,
    var(--color-primary) 2px,
    transparent 2px,
    transparent 4px,
    var(--color-primary) 4px,
    var(--color-primary) 6px,
    transparent 6px,
    transparent 8px,
    var(--color-primary) 8px,
    var(--color-primary) 10px
  );
}

.nav-toggle[aria-expanded="true"] { border-color: var(--color-primary); color: var(--color-primary); }

/* ============================================================
   07 · 手册式章节与栅格
   ============================================================ */
.manual {
  display: grid;
  grid-template-columns: 88px minmax(0, 1fr);
  gap: 0 var(--space-4);
  align-items: start;
}

.manual__rail {
  position: sticky;
  top: 112px;
  border-right: var(--border-thin) solid var(--color-line);
  padding-right: var(--space-3);
}

.manual__body { min-width: 0; }

.split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-4);
}

.section {
  padding-top: var(--section-y);
  padding-bottom: var(--section-y);
}

.section--tight { padding-top: var(--space-6); padding-bottom: var(--space-6); }

.section--alt { background-color: var(--color-surface-alt); }

.section--deep {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.section--deep h1,
.section--deep h2,
.section--deep h3,
.section--deep .chapter__title,
.section--deep .lead,
.section--deep .display-title { color: var(--color-contrast-ink); }

.section--deep .prose,
.section--deep p { color: var(--color-contrast-ink); }

.section--deep a { color: var(--color-contrast-ink); }

.section--deep .text-soft,
.section--deep .text-muted { color: color-mix(in srgb, var(--color-contrast-ink) 70%, var(--color-contrast-surface)); }

.section--deep .rule,
.section--deep .chapter__head { border-color: var(--color-contrast-line); }

.section--deep .chapter__num { color: var(--color-contrast-accent); }

.section--deep .eyebrow { color: var(--color-contrast-accent); border-bottom-color: var(--color-contrast-line); }

.chapter { margin-bottom: var(--section-y); }
.chapter:last-child { margin-bottom: 0; }

.chapter__head {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  padding-bottom: var(--space-2);
  border-bottom: var(--border-thin) solid var(--color-line);
  margin-bottom: var(--space-4);
}

.chapter__num {
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--color-primary);
  flex: 0 0 auto;
}

.chapter__title {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  flex: 1 1 auto;
  min-width: 0;
}

.chapter__meta {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
  flex: 0 0 auto;
}

/* ============================================================
   08 · 索引列表
   ============================================================ */
.index-list {
  border-top: var(--border-thin) solid var(--color-line);
}

.index-list__item {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: var(--space-2);
  padding: var(--space-2) 0;
  border-bottom: var(--border-thin) solid var(--color-line);
  align-items: baseline;
}

.index-list__num {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-primary);
}

.index-list__title {
  font-size: var(--text-base);
  font-weight: 600;
  color: var(--color-ink);
  display: block;
  margin-bottom: 2px;
}

.index-list__desc {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  line-height: 1.7;
  display: block;
}

/* ============================================================
   09 · 要点框
   ============================================================ */
.note {
  position: relative;
  border: var(--border-thin) solid var(--color-line);
  border-left: var(--border-thick) solid var(--color-accent);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface);
  padding: var(--space-3);
  transition: background-color 0.16s ease-out, border-left-width 0.16s ease-out;
}

.note:hover {
  background-color: var(--color-surface-alt);
  border-left-width: 4px;
}

.note__title {
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
  margin: 0 0 var(--space-1);
  line-height: 1.4;
}

.note__body {
  font-size: var(--text-sm);
  line-height: 1.8;
  color: var(--color-ink-soft);
}

.note--primary { border-left-color: var(--color-primary); background-color: var(--color-primary-soft); }
.note--primary:hover { background-color: color-mix(in srgb, var(--color-primary-soft) 70%, var(--color-surface-deep)); }

.note--deep {
  background-color: var(--color-contrast-surface);
  border-color: var(--color-contrast-line);
  border-left-color: var(--color-contrast-accent);
  color: var(--color-contrast-ink);
}

.note--deep:hover { background-color: color-mix(in srgb, var(--color-contrast-surface) 88%, var(--color-contrast-ink)); }
.note--deep .note__title { color: var(--color-contrast-ink); }
.note--deep .note__body { color: color-mix(in srgb, var(--color-contrast-ink) 76%, var(--color-contrast-surface)); }

.note-stack { display: grid; gap: var(--space-2); }

/* ============================================================
   10 · 路径（技能树式服务步骤）
   ============================================================ */
.path { display: grid; gap: 0; }

.path__step {
  position: relative;
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: var(--space-2);
  padding-bottom: var(--space-3);
}

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

.path__step::before {
  content: "";
  position: absolute;
  left: 19px;
  top: 30px;
  bottom: 0;
  width: var(--border-thin);
  background-color: var(--color-line);
}

.path__step:last-child::before { display: none; }

.path__num {
  position: relative;
  z-index: 1;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-primary);
  background-color: var(--color-primary-soft);
  border: var(--border-thin) solid var(--color-primary);
  border-radius: var(--radius-sm);
}

.path__title {
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-heading);
  margin: 0 0 4px;
  padding-top: 8px;
}

.path__desc {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  line-height: 1.75;
}

/* ============================================================
   11 · 数据表
   ============================================================ */
.data-table {
  width: 100%;
  font-size: var(--text-sm);
  border: var(--border-thin) solid var(--color-line);
}

.data-table caption {
  caption-side: top;
  text-align: left;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
  padding-bottom: var(--space-1);
}

.data-table th,
.data-table td {
  padding: 10px var(--space-2);
  text-align: left;
  border-bottom: var(--border-thin) solid var(--color-line);
  vertical-align: top;
}

.data-table thead th {
  background-color: var(--color-primary-soft);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.08em;
  white-space: nowrap;
}

.data-table tbody tr:nth-child(even) { background-color: var(--color-surface-alt); }
.data-table tbody tr:hover { background-color: var(--color-surface-deep); }
.data-table .num { font-family: var(--font-mono); font-variant-numeric: tabular-nums; text-align: right; white-space: nowrap; }

/* ============================================================
   12 · 图片容器
   ============================================================ */
.figure { margin: 0; }

.figure__frame {
  position: relative;
  display: block;
  overflow: hidden;
  width: 100%;
  aspect-ratio: 16 / 9;
  background-color: var(--color-surface-deep);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
}

.figure--tall .figure__frame { aspect-ratio: 4 / 5; }
.figure--wide .figure__frame { aspect-ratio: 21 / 9; }
.figure--square .figure__frame { aspect-ratio: 1 / 1; }

.figure__frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(1) contrast(1.06);
}

.figure__frame::after {
  content: "";
  position: absolute;
  inset: 0;
  background-color: var(--color-primary);
  mix-blend-mode: multiply;
  opacity: 0.5;
  pointer-events: none;
}

.figure--accent .figure__frame::after { background-color: var(--color-accent); opacity: 0.42; }
.figure--deep .figure__frame::after { background-color: var(--color-contrast-surface); opacity: 0.58; mix-blend-mode: multiply; }

.figure__overlay {
  position: absolute;
  inset: auto 0 0 0;
  z-index: 2;
  padding: var(--space-3);
  background: var(--overlay-scrim);
  color: var(--color-contrast-ink);
}

.figure__overlay .figure-value { color: var(--color-contrast-ink); }

.figure__caption {
  margin-top: var(--space-1);
  font-size: var(--text-xs);
  line-height: 1.7;
  color: var(--color-ink-muted);
}

/* ============================================================
   13 · 面包屑
   ============================================================ */
.breadcrumb {
  border-bottom: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface-alt);
}

.breadcrumb ol {
  max-width: var(--container);
  margin: 0 auto;
  padding: 10px var(--gutter);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: var(--text-xs);
  letter-spacing: 0.05em;
  color: var(--color-ink-muted);
}

.breadcrumb li { display: flex; align-items: center; gap: 8px; }

.breadcrumb li + li::before {
  content: "/";
  color: var(--color-line);
  font-family: var(--font-mono);
}

.breadcrumb a { color: var(--color-ink-soft); }
.breadcrumb a:hover { color: var(--color-primary); }
.breadcrumb [aria-current="page"] { color: var(--color-ink); font-weight: 600; }

/* ============================================================
   14 · 页脚
   ============================================================ */
.site-footer { margin-top: var(--section-y); }

.footer-inner {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding-left: var(--gutter);
  padding-right: var(--gutter);
}

.footer-tier { padding: var(--space-6) 0; }

.footer-tier--nav {
  background-color: var(--color-surface);
  border-top: var(--border-thick) solid var(--color-primary);
}

.footer-tier--topics {
  background-color: var(--color-surface-alt);
  border-top: var(--border-thin) solid var(--color-line);
}

.footer-tier--legal {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-top: var(--border-thin) solid var(--color-contrast-line);
  padding-top: var(--space-4);
  padding-bottom: var(--space-4);
}

.footer-tier__head {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  padding-bottom: var(--space-2);
  margin-bottom: var(--space-3);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.footer-tier__num {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-primary);
  letter-spacing: -0.02em;
}

.footer-tier__title {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  flex: 1 1 auto;
}

.footer-tier__hint {
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
  font-family: var(--font-mono);
}

.footer-index {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 var(--space-4);
}

.footer-index__item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 0 var(--space-2);
  padding: 10px 0;
  border-bottom: var(--border-thin) solid var(--color-line);
  align-items: baseline;
}

.footer-index__num {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  letter-spacing: 0.04em;
}

.footer-index__link {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-ink);
  text-decoration: none;
  border-left: var(--border-thick) solid transparent;
  padding-left: 6px;
  transition: border-left-color 0.16s ease-out, color 0.16s ease-out;
}

.footer-index__link:hover {
  color: var(--color-primary);
  border-left-color: var(--color-accent);
  text-decoration: none;
}

.footer-index__note {
  grid-column: 2 / -1;
  font-size: var(--text-xs);
  line-height: 1.7;
  color: var(--color-ink-soft);
  padding-left: 6px;
  margin-top: 2px;
}

.topic-index {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  border-top: var(--border-thin) solid var(--color-line);
}

.topic-index__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px var(--space-3) 10px 0;
  margin-right: var(--space-3);
  border-bottom: var(--border-thin) solid var(--color-line);
  font-size: var(--text-sm);
  color: var(--color-ink);
}

.topic-index__num {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-accent);
  border: var(--border-thin) solid var(--color-accent);
  border-radius: var(--radius-sm);
  padding: 0 4px;
  line-height: 1.6;
}

.footer-legal {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: var(--space-3) var(--space-4);
  align-items: start;
}

.footer-legal__brand {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.footer-legal__name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-contrast-ink);
  letter-spacing: 0.02em;
}

.footer-legal__desc {
  font-size: var(--text-xs);
  letter-spacing: 0.05em;
  color: color-mix(in srgb, var(--color-contrast-ink) 62%, var(--color-contrast-surface));
}

.footer-legal__list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  align-items: center;
}

.footer-legal__item a {
  font-size: var(--text-sm);
  color: var(--color-contrast-ink);
  text-decoration: none;
  border-bottom: var(--border-thin) solid var(--color-contrast-accent);
  padding-bottom: 2px;
  transition: color 0.16s ease-out;
}

.footer-legal__item a:hover { color: var(--color-contrast-accent); text-decoration: none; }

.footer-legal__meta {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-2) var(--space-3);
  padding-top: var(--space-3);
  border-top: var(--border-thin) solid var(--color-contrast-line);
}

.footer-legal__pair { display: flex; flex-direction: column; gap: 2px; }

.footer-legal__label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-contrast-accent);
}

.footer-legal__value {
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-contrast-ink);
  word-break: break-word;
}

.footer-legal__bottom {
  grid-column: 1 / -1;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--space-2);
  margin-top: var(--space-3);
  padding-top: var(--space-2);
  border-top: var(--border-thin) solid var(--color-contrast-line);
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
  color: color-mix(in srgb, var(--color-contrast-ink) 62%, var(--color-contrast-surface));
}

.footer-legal__domain { font-family: var(--font-mono); }

/* ============================================================
   15 · 脚本注入件
   ============================================================ */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0;
  height: 2px;
  z-index: 90;
  background-color: var(--color-accent);
  pointer-events: none;
  transition: width 0.1s linear;
}

.to-top {
  position: fixed;
  right: var(--space-3);
  bottom: var(--space-3);
  z-index: 70;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 12px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-primary-ink);
  background-color: var(--color-primary);
  border: var(--border-thin) solid var(--color-primary);
  border-radius: var(--radius-sm);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.16s ease-out, visibility 0.16s ease-out, background-color 0.16s ease-out;
}

.to-top:hover { background-color: color-mix(in srgb, var(--color-primary) 84%, var(--color-contrast-surface)); }

.to-top[data-visible="true"] { opacity: 1; visibility: visible; }

/* 目录轨道 */
.toc-rail__title {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
  margin-bottom: var(--space-2);
  display: block;
}

.toc-rail__item { display: block; }

.toc-rail__link {
  display: block;
  padding: 7px 0 7px 10px;
  font-size: var(--text-sm);
  line-height: 1.5;
  color: var(--color-ink-soft);
  border-left: var(--border-thick) solid transparent;
  text-decoration: none;
  transition: color 0.16s ease-out, border-left-color 0.16s ease-out;
}

.toc-rail__link:hover {
  color: var(--color-ink);
  border-left-color: color-mix(in srgb, var(--color-primary) 40%, var(--color-surface));
  text-decoration: none;
}

.toc-rail__link[aria-current="true"] {
  color: var(--color-primary);
  border-left-color: var(--color-primary);
  font-weight: 600;
}

/* 显现 */
@media (prefers-reduced-motion: no-preference) {
  .js [data-reveal] {
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 0.3s ease-out, transform 0.3s ease-out;
  }
  .js [data-reveal][data-revealed="true"] {
    opacity: 1;
    transform: none;
  }
}

/* ============================================================
   16 · 响应式
   ============================================================ */
@media (min-width: 721px) {
  .split--7-5 { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); }
  .split--8-4 { grid-template-columns: minmax(0, 8fr) minmax(0, 4fr); }
  .split--5-7 { grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); }
}

@media (max-width: 1024px) {
  .manual { grid-template-columns: 64px minmax(0, 1fr); gap: 0 var(--space-3); }
  .brand__line { display: none; }
  .site-nav__list a { padding: 9px 10px; font-size: var(--text-xs); }
  .footer-legal__meta { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 880px) {
  html { scroll-padding-top: 96px; }

  .header-bar__inner { padding: 8px var(--gutter); }

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

  .site-nav {
    display: none;
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    z-index: 65;
    background-color: var(--color-surface);
    border-top: var(--border-thin) solid var(--color-line);
    border-bottom: var(--border-thick) solid var(--color-primary);
    max-height: calc(100vh - 140px);
    overflow-y: auto;
  }

  .site-nav[data-open="true"] { display: block; }

  .site-nav__list { flex-direction: column; align-items: stretch; }

  .site-nav__item + .site-nav__item { border-left: 0; border-top: var(--border-thin) solid var(--color-line); }

  .site-nav__list a {
    padding: 14px var(--gutter);
    font-size: var(--text-base);
    color: var(--color-ink);
    border-left: var(--border-thick) solid transparent;
  }

  .site-nav__list a:hover { border-left-color: var(--color-primary); }

  .site-nav__list a[aria-current="page"] {
    border-left-color: var(--color-primary);
    background-color: var(--color-primary-soft);
  }

  .header-status__text { display: none; }
  .header-status__icp { margin-left: auto; }

  .manual { grid-template-columns: minmax(0, 1fr); gap: var(--space-3) 0; }

  .manual__rail {
    position: static;
    border-right: 0;
    border-top: var(--border-thin) solid var(--color-line);
    border-bottom: var(--border-thin) solid var(--color-line);
    padding: var(--space-2) 0;
  }

  .toc-rail__item { display: inline-block; }
  .toc-rail__link { display: inline-block; padding: 5px 10px 5px 8px; }

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

  .footer-tier { padding: var(--space-4) 0; }

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

@media (max-width: 560px) {
  :root { --section-y: 56px; }

  .chapter__head { flex-wrap: wrap; gap: var(--space-1); }
  .chapter__meta { flex: 1 0 100%; }
  .chapter__title { font-size: var(--text-lg); }
  .chapter__num { font-size: var(--text-base); }

  .header-status__label { display: none; }
  .header-status__icp { margin-left: 0; font-size: var(--text-xs); }

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

  .to-top { right: var(--space-2); bottom: var(--space-2); }

  .index-list__item { grid-template-columns: minmax(0, 1fr); gap: 2px; }
  .index-list__num { display: block; }
}