:root {
  --color-surface: #eeedec;
  --color-surface-alt: #e6e4e3;
  --color-surface-deep: #dad8d7;
  --color-ink: #49413c;
  --color-ink-soft: #6f655d;
  --color-ink-muted: #8a7e75;
  --color-line: #d0cecc;
  --color-primary: #9f6a41;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #e3dbd4;
  --color-accent: #306ecf;
  --color-accent-ink: #ffffff;
  --color-highlight: #ccd6e7;
  --color-focus: #2165cf;
  --color-contrast-surface: #181310;
  --color-contrast-ink: #e7e5e4;
  --color-contrast-line: #46413f;
  --color-contrast-accent: #497fd5;
  --overlay-scrim: linear-gradient(180deg, rgba(24, 19, 16, 0.35) 0%, rgba(24, 19, 16, 0.72) 55%, rgba(24, 19, 16, 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: 10.4px;
  --text-sm: 13.9px;
  --text-base: 16px;
  --text-lg: 21.3px;
  --text-xl: 28.4px;
  --text-2xl: 37.9px;
  --text-3xl: 50.5px;
  --text-4xl: 67.3px;
  --text-display: clamp(38px, 7.7vw, 99px);
  --text-figure: clamp(31px, 5.5vw, 71px);
  --weight-heading: 632;
  --weight-body: 400;
  --leading-body: 1.77;
  --leading-heading: 1.26;
  --tracking-heading: -0.001em;
  --radius-sm: 1px;
  --radius-md: 1px;
  --radius-lg: 1px;
  --radius-pill: 1px;
  --border-thin: 1px;
  --border-thick: 1px;
  --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: 1140px;
  --measure: 67ch;
  --gutter: 24px;
  --section-y: 93px;
  --section-y-lg: 130px;
}

/* ============================================================
   1. Reset 与纸面基底
   ============================================================ */
*,
*::before,
*::after { box-sizing: border-box; }

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

body {
  margin: 0;
  background-color: var(--color-surface);
  background-image:
    repeating-linear-gradient(0deg, rgba(73, 65, 60, 0.022) 0 1px, transparent 1px 5px),
    repeating-linear-gradient(90deg, rgba(73, 65, 60, 0.014) 0 1px, transparent 1px 7px);
  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: 0.006em;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

img, svg, video, picture { display: block; max-width: 100%; }
img { height: auto; }
button, input, select, textarea { font: inherit; color: inherit; }
ul, ol { margin: 0; padding: 0; list-style: none; }
figure, blockquote, dl, dd { margin: 0; }
hr { border: 0; }
[hidden] { display: none !important; }

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

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

#main-content { display: block; }

/* ============================================================
   2. 中文排版
   ============================================================ */
h1, h2, h3, h4, h5, h6 {
  margin: 0 0 var(--space-3);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
  text-wrap: balance;
}

h1 { font-size: var(--text-3xl); }
h2 { font-size: var(--text-2xl); }
h3 { font-size: var(--text-xl); }
h4 { font-size: var(--text-lg); }
h5, h6 { font-size: var(--text-base); }

p { margin: 0 0 var(--space-3); }

a { color: var(--color-accent); text-decoration: none; }
a:hover { color: var(--color-focus); }

strong { font-weight: 600; }
small { font-size: var(--text-sm); }

.display-title {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: 1.02;
  letter-spacing: -0.018em;
  margin: 0 0 var(--space-3);
  color: var(--color-ink);
}

.stat-figure {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  line-height: 1;
  color: var(--color-primary);
  letter-spacing: -0.02em;
}

.lede {
  max-width: 46ch;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  line-height: 1.7;
  color: var(--color-ink-soft);
}

.meta-mono,
.mono {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}

/* 正文容器 */
.prose {
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink);
}
.prose > h2 { margin: var(--space-8) 0 var(--space-3); }
.prose > h3 { margin: var(--space-6) 0 var(--space-2); }
.prose ul,
.prose ol { margin: 0 0 var(--space-3); }
.prose li {
  position: relative;
  padding-left: var(--space-3);
  margin-bottom: var(--space-1);
}
.prose li::before {
  content: "—";
  position: absolute;
  left: 0;
  color: var(--color-primary);
}
.prose a {
  color: var(--color-accent);
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-accent) 45%, transparent);
}
.prose a:hover { border-bottom-color: var(--color-accent); }
.prose blockquote {
  margin: var(--space-6) 0;
  padding: var(--space-3) var(--space-4);
  background-color: var(--color-highlight);
  border-left: 3px solid var(--color-primary);
  color: var(--color-ink);
}
.prose blockquote p:last-child { margin-bottom: 0; }
.prose code,
.prose kbd {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  background-color: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: 1px 5px;
}

/* ============================================================
   3. 版心与栅格
   ============================================================ */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--space-2);
}
@media (min-width: 768px) {
  .container { padding-inline: var(--space-3); }
}

.section { padding-block: var(--section-y); }
.section--lg { padding-block: var(--section-y-lg); }
.section--tight { padding-block: var(--space-6); }

.grid { display: grid; gap: var(--space-3); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--asym { grid-template-columns: minmax(0, 1.618fr) minmax(0, 1fr); }

/* 非对称双栏：宽正文 + 窄旁注 */
.cols {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  column-gap: var(--gutter);
  row-gap: var(--space-6);
}
.cols__body { grid-column: 1 / span 8; min-width: 0; }
.cols__note { grid-column: 9 / -1; min-width: 0; }
.cols--flip .cols__body { grid-column: 5 / -1; }
.cols--flip .cols__note { grid-column: 1 / span 3; }

@media (max-width: 960px) {
  .cols__body,
  .cols__note,
  .cols--flip .cols__body,
  .cols--flip .cols__note { grid-column: 1 / -1; }
  .grid--2,
  .grid--3,
  .grid--asym { grid-template-columns: minmax(0, 1fr); }
}

/* ============================================================
   4. 分隔语言：细线 / 双线 / 粗线
   ============================================================ */
.rule {
  height: var(--border-thin);
  margin: 0;
  border: 0;
  background-color: var(--color-line);
}
.rule--double {
  height: 5px;
  margin: 0;
  border: 0;
  background-color: transparent;
  background-image: linear-gradient(var(--color-ink) 0 0), linear-gradient(var(--color-ink) 0 0);
  background-size: 100% 1px, 100% 1px;
  background-position: 0 0, 0 100%;
  background-repeat: no-repeat;
}
.rule--thick {
  height: 3px;
  margin: 0;
  border: 0;
  background-color: var(--color-primary);
}

/* ============================================================
   5. 印刷标签 / 章节头 / 大编号
   ============================================================ */
.label-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.18em;
  line-height: 1.6;
  color: var(--color-primary);
  background-color: var(--color-primary-soft);
  border-left: 2px solid var(--color-primary);
  border-radius: var(--radius-sm);
  padding: 4px 12px;
}
.label-tag--ink {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-left-color: var(--color-primary);
}

.section-head {
  display: grid;
  gap: var(--space-2);
  padding-top: var(--space-3);
  border-top: var(--border-thin) solid var(--color-ink);
  margin-bottom: var(--space-6);
}
.section-head__num {
  font-family: var(--font-heading);
  font-size: var(--text-figure);
  font-weight: var(--weight-heading);
  line-height: 0.86;
  letter-spacing: -0.03em;
  color: var(--color-primary);
}
.section-head__title {
  margin: 0;
  font-size: var(--text-2xl);
}
.section-head__meta {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}
@media (min-width: 860px) {
  .section-head {
    grid-template-columns: auto minmax(0, 1fr) auto;
    align-items: end;
    column-gap: var(--space-4);
  }
  .section-head__num { grid-row: 1; }
  .section-head__title { grid-row: 1; }
  .section-head__meta { grid-row: 1; text-align: right; }
}

/* ============================================================
   6. 旁注栏
   ============================================================ */
.margin-note {
  background-color: var(--color-surface-alt);
  border-top: 2px solid var(--color-primary);
  border-radius: var(--radius-sm);
  padding: var(--space-3);
  font-size: var(--text-sm);
  line-height: 1.5;
  color: var(--color-ink-soft);
}
.margin-note__label {
  display: block;
  margin-bottom: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-primary);
}
.margin-note p:last-child { margin-bottom: 0; }
.margin-note + .margin-note { margin-top: var(--space-3); }

/* ============================================================
   7. 深墨全宽条带
   ============================================================ */
.band-dark {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-top: var(--border-thick) solid var(--color-primary);
  border-bottom: var(--border-thick) solid var(--color-primary);
}
.band-dark__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2) var(--space-6);
  padding-block: var(--space-6);
}
.band-dark a { color: var(--color-contrast-accent); }
.band-dark .label-tag {
  background-color: transparent;
  color: var(--color-contrast-ink);
  border-left-color: var(--color-primary);
}
.band-dark .stat-figure { color: var(--color-contrast-accent); }
.band-dark .meta-mono { color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent); }
.band-dark__title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  color: var(--color-contrast-ink);
}

/* ============================================================
   8. 容器形态：索引卡 / 状态面板 / 条目流 / 表格
   ============================================================ */
.index-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  background-color: transparent;
  border: var(--border-thin) solid var(--color-line);
  border-top: 3px solid var(--color-ink);
  border-radius: var(--radius-sm);
  padding: var(--space-3);
}
.index-card__num {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-ink-muted);
}
.index-card__title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  line-height: 1.35;
}
.index-card__body {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}
.index-card__meta {
  margin-top: auto;
  padding-top: var(--space-2);
  border-top: var(--border-thin) solid var(--color-line);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.state-panel {
  background-color: var(--color-surface-deep);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
}
.state-panel__row {
  display: flex;
  justify-content: space-between;
  gap: var(--space-2);
  padding-block: 6px;
  border-bottom: var(--border-thin) solid var(--color-line);
}
.state-panel__row:last-child { border-bottom: 0; }
.state-panel__key { color: var(--color-ink-muted); }
.state-panel__value { color: var(--color-ink); }
.state-panel__value--on { color: var(--color-accent); }
.state-panel__value--key { color: var(--color-primary); }

.entry-list { border-top: var(--border-thin) solid var(--color-ink); }
.entry {
  display: grid;
  grid-template-columns: 62px minmax(0, 1fr) auto;
  align-items: baseline;
  gap: var(--space-1) var(--space-3);
  padding-block: var(--space-3);
  border-bottom: var(--border-thin) solid var(--color-line);
}
.entry__num {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-primary);
}
.entry__title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  line-height: 1.35;
}
.entry__meta {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
  text-align: right;
}
@media (max-width: 700px) {
  .entry { grid-template-columns: 46px minmax(0, 1fr); }
  .entry__meta { grid-column: 2; text-align: left; }
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-sm);
}
.data-table th,
.data-table td {
  text-align: left;
  vertical-align: top;
  padding: var(--space-2);
  border-bottom: var(--border-thin) solid var(--color-line);
}
.data-table thead th {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
  border-bottom: 2px solid var(--color-ink);
}
.data-table tbody tr:nth-child(odd) { background-color: var(--color-surface-alt); }

/* ============================================================
   9. 图片容器（展签式图注）
   ============================================================ */
.figure {
  margin: 0;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface-alt);
  overflow: hidden;
}
.figure__media {
  position: relative;
  aspect-ratio: 4 / 3;
  overflow: hidden;
  background-color: var(--color-surface-deep);
}
.figure--wide .figure__media { aspect-ratio: 16 / 9; }
.figure--square .figure__media { aspect-ratio: 1 / 1; }
.figure__media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.72) contrast(1.03);
}
.figure__scrim {
  position: absolute;
  inset: 0;
  background-image: var(--overlay-scrim);
}
.figure__overlay-text {
  position: absolute;
  left: var(--space-3);
  right: var(--space-3);
  bottom: var(--space-3);
  color: var(--color-contrast-ink);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  line-height: 1.4;
}
.figure__tag {
  position: absolute;
  left: 0;
  bottom: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  padding: 4px 10px;
}
.figure__caption {
  padding: var(--space-2) var(--space-3);
  border-top: var(--border-thin) solid var(--color-line);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}

/* ============================================================
   10. 按钮与链接
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 10px 18px;
  border: var(--border-thin) solid var(--color-ink);
  border-radius: var(--radius-sm);
  background-color: transparent;
  color: var(--color-ink);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  line-height: 1.4;
  cursor: pointer;
  transition: background-color 120ms linear, color 120ms linear, border-color 120ms linear;
}
.btn--primary {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  border-color: var(--color-primary);
}
.btn--primary:hover {
  background-color: color-mix(in srgb, var(--color-primary) 84%, var(--color-contrast-surface));
  color: var(--color-primary-ink);
}
.btn--ink {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-color: var(--color-contrast-surface);
}
.btn--ink:hover {
  background-color: color-mix(in srgb, var(--color-contrast-surface) 82%, var(--color-primary));
  color: var(--color-contrast-ink);
}
.btn--ghost:hover {
  background-color: var(--color-surface-deep);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.link-underline {
  position: relative;
  color: var(--color-accent);
}
.link-underline::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -2px;
  height: 1px;
  background-color: currentColor;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 120ms linear;
}
.link-underline:hover::after,
.link-underline:focus-visible::after { transform: scaleX(1); }

/* ============================================================
   11. 面包屑 / 锚点目录 / 进度条
   ============================================================ */
.breadcrumb {
  padding-block: var(--space-3);
  border-bottom: var(--border-thin) solid var(--color-line);
  margin-bottom: var(--space-6);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}
.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
}
.breadcrumb li + li::before {
  content: "／";
  margin-right: var(--space-1);
  color: var(--color-line);
}
.breadcrumb a { color: var(--color-ink-soft); }
.breadcrumb a:hover { color: var(--color-accent); }
.breadcrumb [aria-current="page"] { color: var(--color-primary); }

.toc {
  border-top: 2px solid var(--color-ink);
  padding-top: var(--space-2);
  font-size: var(--text-sm);
}
.toc__title {
  margin-bottom: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
}
.toc a {
  display: block;
  padding: 6px 0;
  border-bottom: var(--border-thin) solid var(--color-line);
  color: var(--color-ink-soft);
}
.toc a:hover { color: var(--color-primary); }

.read-progress {
  position: fixed;
  top: 0;
  right: 0;
  width: 2px;
  height: 100vh;
  z-index: 30;
  background-color: color-mix(in srgb, var(--color-line) 55%, transparent);
  pointer-events: none;
}
.read-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  background-color: var(--color-primary);
  transform: scaleY(0);
  transform-origin: top center;
}

/* ============================================================
   12. 标签页与筛选
   ============================================================ */
.tabs { margin-block: var(--space-4); }
.tabs__list {
  display: flex;
  flex-wrap: wrap;
  border-bottom: 2px solid var(--color-ink);
}
.tab {
  appearance: none;
  margin-bottom: -2px;
  padding: var(--space-2) var(--space-3);
  border: 0;
  border-bottom: 2px solid transparent;
  background-color: transparent;
  color: var(--color-ink-soft);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  cursor: pointer;
  transition: color 120ms linear, border-color 120ms linear;
}
.tab:hover { color: var(--color-ink); }
.tab[aria-selected="true"] {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}
.tabpanel { padding-top: var(--space-3); }
.tabpanel:not([hidden]) { animation: panel-in 180ms ease-out; }
@keyframes panel-in {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  padding-block: var(--space-2);
  border-top: var(--border-thin) solid var(--color-ink);
  border-bottom: var(--border-thin) solid var(--color-line);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
}
.filter-bar__label { color: var(--color-ink-muted); margin-right: var(--space-1); }
.filter-btn {
  appearance: none;
  padding: 4px 10px;
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-sm);
  background-color: transparent;
  color: var(--color-ink-soft);
  font: inherit;
  letter-spacing: 0.08em;
  cursor: pointer;
  transition: color 120ms linear, border-color 120ms linear, background-color 120ms linear;
}
.filter-btn:hover { color: var(--color-ink); border-color: var(--color-line); }
.filter-btn[aria-pressed="true"] {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background-color: var(--color-primary-soft);
}
.filter-count { margin-left: auto; color: var(--color-ink-muted); }

/* ============================================================
   13. 页头
   ============================================================ */
.skip-link {
  position: fixed;
  top: var(--space-2);
  left: var(--space-2);
  z-index: 100;
  padding: 10px 16px;
  border: var(--border-thin) solid var(--color-primary);
  border-radius: var(--radius-sm);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  transform: translateY(-160%);
  transition: transform 120ms linear;
}
.skip-link:focus { transform: translateY(0); color: var(--color-contrast-ink); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background-color: var(--color-surface);
  border-bottom: var(--border-thick) solid var(--color-ink);
  box-shadow: var(--shadow-1);
}

.site-header__frame {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--space-2);
}
@media (min-width: 768px) {
  .site-header__frame { padding-inline: var(--space-3); }
}

.site-header__masthead {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-2) var(--space-4);
  padding-block: var(--space-3) var(--space-2);
}

.brand {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin-right: auto;
  color: var(--color-ink);
}
.brand:hover { color: var(--color-ink); }
.brand__mark {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  line-height: 1.15;
  letter-spacing: 0.04em;
}
.brand__sub {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-ink-muted);
}

.batch-stamp {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  margin: 0;
  padding-left: var(--space-2);
  border-left: 2px solid var(--color-primary);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
}
.batch-stamp__key { color: var(--color-ink-muted); }
.batch-stamp__value { color: var(--color-primary); }

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  min-height: 40px;
  padding: 8px 12px;
  border: var(--border-thin) solid var(--color-ink);
  border-radius: var(--radius-sm);
  background-color: transparent;
  color: var(--color-ink);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  cursor: pointer;
  transition: border-color 120ms linear, color 120ms linear;
}
.nav-toggle:hover { border-color: var(--color-primary); color: var(--color-primary); }
.nav-toggle__bars {
  display: block;
  width: 14px;
  height: 9px;
  background-color: transparent;
  background-image:
    linear-gradient(var(--color-ink) 0 0),
    linear-gradient(var(--color-ink) 0 0),
    linear-gradient(var(--color-ink) 0 0);
  background-size: 100% 1px, 100% 1px, 100% 1px;
  background-position: 0 0, 0 50%, 0 100%;
  background-repeat: no-repeat;
}
.nav-toggle[aria-expanded="true"] { border-color: var(--color-primary); color: var(--color-primary); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars {
  background-image:
    linear-gradient(var(--color-primary) 0 0),
    linear-gradient(var(--color-primary) 0 0);
  background-size: 100% 1px, 100% 1px;
  background-position: 0 20%, 0 80%;
}

/* 目录框架导航 */
.site-nav {
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  gap: var(--space-3);
  border-top: var(--border-thin) solid var(--color-line);
}
.site-nav__list {
  display: flex;
  flex-wrap: wrap;
  border-right: var(--border-thin) solid var(--color-line);
}
.site-nav__item { display: flex; }
.site-nav__link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 6px;
  padding: var(--space-2) var(--space-3);
  border-left: var(--border-thin) solid var(--color-line);
  color: var(--color-ink);
  font-size: var(--text-sm);
  line-height: 1.5;
  transition: color 120ms linear, background-color 120ms linear;
}
.site-nav__link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  background-color: var(--color-primary);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 120ms linear;
}
.site-nav__link:hover,
.site-nav__link:focus-visible { color: var(--color-primary); background-color: var(--color-surface-alt); }
.site-nav__link:hover::after,
.site-nav__link:focus-visible::after { transform: scaleX(1); }
.site-nav__link[aria-current="page"] {
  color: var(--color-primary);
  background-color: var(--color-surface-deep);
}
.site-nav__link[aria-current="page"]::after { transform: scaleX(1); }
.site-nav__link[aria-current="page"]::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background-color: var(--color-primary);
}
.site-nav__num {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}
.site-nav__link[aria-current="page"] .site-nav__num { color: var(--color-primary); }
.site-nav__label { white-space: nowrap; }
.site-nav__utility {
  align-self: center;
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
  white-space: nowrap;
}
.site-nav__utility-link {
  color: var(--color-ink-muted);
  border-bottom: var(--border-thin) solid var(--color-line);
}
.site-nav__utility-link:hover { color: var(--color-accent); border-bottom-color: var(--color-accent); }

@media (max-width: 1040px) {
  .site-nav__utility { display: none; }
}
@media (max-width: 900px) {
  .site-header__masthead { align-items: center; padding-block: var(--space-2); }
  .brand__mark { font-size: var(--text-lg); }
  .nav-toggle { display: inline-flex; }
  .batch-stamp { order: 3; flex-basis: 100%; margin-top: var(--space-1); }
  .site-nav {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    border-top: var(--border-thin) solid var(--color-ink);
  }
  .site-nav[data-open] {
    display: flex;
    max-height: 68vh;
    overflow-y: auto;
    padding-bottom: var(--space-2);
  }
  .site-nav__list { flex-direction: column; border-right: 0; }
  .site-nav__item { display: block; }
  .site-nav__link {
    padding: var(--space-2) var(--space-2) var(--space-2) var(--space-3);
    border-left: 0;
    border-bottom: var(--border-thin) solid var(--color-line);
    font-size: var(--text-base);
  }
  .site-nav__link::after { bottom: 0; }
  .site-nav__utility { align-self: flex-start; padding: var(--space-2) var(--space-2) 0; white-space: normal; }
}

/* ============================================================
   14. 页脚
   ============================================================ */
.site-footer {
  margin-top: var(--section-y);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-top: var(--border-thick) solid var(--color-contrast-surface);
}
.site-footer__rule {
  height: 5px;
  background-color: transparent;
  background-image:
    linear-gradient(var(--color-primary) 0 0),
    linear-gradient(var(--color-contrast-line) 0 0);
  background-size: 100% 2px, 100% 1px;
  background-position: 0 0, 0 100%;
  background-repeat: no-repeat;
}
.site-footer__frame {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2) var(--space-6);
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-4) var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.9;
  letter-spacing: 0.08em;
}
@media (min-width: 768px) {
  .site-footer__frame { padding-inline: var(--space-3); }
}
.site-footer__col { min-width: 0; }
.site-footer__brand {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  letter-spacing: 0.16em;
  color: var(--color-contrast-ink);
}
.site-footer__note {
  margin: 2px 0 0;
  color: color-mix(in srgb, var(--color-contrast-ink) 58%, transparent);
}
.site-footer__links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1) var(--space-4);
}
.site-footer__links a {
  color: var(--color-contrast-accent);
  border-bottom: var(--border-thin) solid transparent;
  transition: border-color 120ms linear;
}
.site-footer__links a:hover {
  color: var(--color-contrast-accent);
  border-bottom-color: var(--color-contrast-accent);
}
.site-footer__col--meta {
  margin-left: auto;
  text-align: left;
  color: color-mix(in srgb, var(--color-contrast-ink) 72%, transparent);
}
.site-footer__col--meta p { margin: 0; }
.site-footer__legal { color: var(--color-contrast-ink); }

@media (max-width: 900px) {
  .site-footer__frame { flex-direction: column; align-items: flex-start; gap: var(--space-3); }
  .site-footer__col--meta { margin-left: 0; }
}

/* ============================================================
   15. 工具类
   ============================================================ */
.is-hidden { display: none !important; }
.text-soft { color: var(--color-ink-soft); }
.text-muted { color: var(--color-ink-muted); }
.text-primary { color: var(--color-primary); }
.stack > * + * { margin-top: var(--space-3); }
.stack-lg > * + * { margin-top: var(--space-6); }

/* ============================================================
   16. 动效与无障碍降级
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  .tabpanel:not([hidden]) { animation: none; }
  .read-progress__bar { transition: none; }
}