:root {
  --color-surface: #fcfcfc;
  --color-surface-alt: #f3f3f4;
  --color-surface-deep: #e6e7e8;
  --color-ink: #474952;
  --color-ink-soft: #6c6f7a;
  --color-ink-muted: #797c86;
  --color-line: #dbdcdd;
  --color-primary: #70768a;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #e8e9ec;
  --color-accent: #3155ce;
  --color-accent-ink: #ffffff;
  --color-highlight: #d7def4;
  --color-focus: #244edb;
  --color-contrast-surface: #202124;
  --color-contrast-ink: #e4e5e7;
  --color-contrast-line: #4b4c4f;
  --color-contrast-accent: #6b85dc;
  --overlay-scrim: linear-gradient(180deg, rgba(32, 33, 36, 0.35) 0%, rgba(32, 33, 36, 0.72) 55%, rgba(32, 33, 36, 0.92) 100%);
  --font-heading: STZhongsong, "Source Han Serif SC", "Songti SC", SimSun, serif;
  --font-body: "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, Menlo, Consolas, monospace;
  --text-xs: 8.3px;
  --text-sm: 13.4px;
  --text-base: 17px;
  --text-lg: 27.5px;
  --text-xl: 44.5px;
  --text-2xl: 72.0px;
  --text-3xl: 116.5px;
  --text-4xl: 188.5px;
  --text-display: clamp(44px, 9.1vw, 116px);
  --text-figure: clamp(37px, 6.6vw, 84px);
  --weight-heading: 353;
  --weight-body: 400;
  --leading-body: 1.81;
  --leading-heading: 1.19;
  --tracking-heading: 0.027em;
  --radius-sm: 0px;
  --radius-md: 0px;
  --radius-lg: 0px;
  --radius-pill: 0px;
  --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: 1120px;
  --measure: 65ch;
  --gutter: 32px;
  --section-y: 155px;
  --section-y-lg: 217px;
}

/* ---------------------------------------------------------------
   1. 重置与基础排版
   --------------------------------------------------------------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body {
  margin: 0;
  background: 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);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

main { display: block; }

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

button,
input,
select,
textarea { font: inherit; color: inherit; }

ul,
ol { margin: 0; padding: 0; }

a {
  color: inherit;
  text-decoration: none;
}

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-primary);
}

h1 { font-size: var(--text-display); }
h2 { font-size: var(--text-xl); }
h3 { font-size: calc(var(--text-base) * 1.25); }
h4, h5, h6 { font-size: var(--text-base); }

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

:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 200;
  padding: var(--space-2) var(--space-3);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  letter-spacing: 0.12em;
  transform: translateY(-120%);
  transition: transform 0.24s ease-out;
}

.skip-link:focus {
  transform: translateY(0);
}

/* ---------------------------------------------------------------
   2. 布局工具
   --------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--space-4);
}

.grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--gutter);
}

.grid > * { min-width: 0; }

.span-3 { grid-column: span 3; }
.span-4 { grid-column: span 4; }
.span-5 { grid-column: span 5; }
.span-6 { grid-column: span 6; }
.span-7 { grid-column: span 7; }
.span-8 { grid-column: span 8; }
.span-9 { grid-column: span 9; }
.span-12 { grid-column: span 12; }

.section { padding-block: var(--section-y); }
.section-lg { padding-block: var(--section-y-lg); }
.section-tight { padding-block: var(--space-8); }

/* ---------------------------------------------------------------
   3. 文字层级与展签
   --------------------------------------------------------------- */
.prose {
  color: var(--color-ink);
  max-width: var(--measure);
}

.prose > * + * { margin-top: var(--space-3); }

.prose h2,
.prose h3 { margin-top: var(--space-6); }

.prose ul,
.prose ol {
  padding-left: var(--space-4);
  list-style: none;
}

.prose li { position: relative; }
.prose li::before {
  content: "";
  position: absolute;
  left: calc(var(--space-4) * -1);
  top: 0.85em;
  width: 12px;
  border-top: var(--border-thin) dotted var(--color-line);
}

.prose a {
  color: var(--color-accent);
  border-bottom: var(--border-thin) dotted color-mix(in srgb, var(--color-accent) 45%, transparent);
}

.prose a:hover { border-bottom-style: solid; }

.eyebrow {
  margin: 0;
  font-size: var(--text-xs);
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.lede {
  margin: 0;
  font-size: var(--text-lg);
  line-height: 1.5;
  color: var(--color-ink-soft);
  max-width: var(--measure);
}

.caption {
  margin: 0;
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-ink-soft);
  max-width: calc(var(--measure) / 2);
}

.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.01em;
}

.data-figure {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: var(--weight-body);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--color-accent);
  font-variant-numeric: tabular-nums;
}

.data-label {
  display: block;
  margin-top: var(--space-2);
  font-size: var(--text-xs);
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.tag {
  display: inline-flex;
  align-items: center;
  padding: 2px var(--space-2);
  font-size: var(--text-xs);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-ink-soft);
  border: var(--border-thin) dotted var(--color-line);
}

/* ---------------------------------------------------------------
   4. 分隔语言：点线与虚线
   --------------------------------------------------------------- */
.rule-dotted {
  border: 0;
  border-top: var(--border-thin) dotted var(--color-line);
  margin: 0;
}

.rule-dashed {
  border: 0;
  border-top: var(--border-thin) dashed var(--color-line);
  margin: 0;
}

.band-dark {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.band-dark h1,
.band-dark h2,
.band-dark h3,
.band-dark h4 {
  color: var(--color-contrast-ink);
}

.band-dark a { color: var(--color-contrast-accent); }

.band-dark .data-figure { color: var(--color-contrast-accent); }

.band-dark .caption,
.band-dark .eyebrow,
.band-dark .data-label,
.band-dark .lede { color: color-mix(in srgb, var(--color-contrast-ink) 68%, transparent); }

.band-dark .rule-dotted,
.band-dark .rule-dashed,
.band-dark hr { border-color: var(--color-contrast-line); }

.highlight-row {
  background: var(--color-highlight);
}

/* ---------------------------------------------------------------
   5. 按钮与筛选块
   --------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 13px var(--space-4);
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  letter-spacing: 0.14em;
  line-height: 1.2;
  cursor: pointer;
  transition: background-color 0.24s ease-out, color 0.24s ease-out, border-color 0.24s ease-out;
}

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

.btn-primary:hover {
  background: color-mix(in srgb, var(--color-accent) 82%, var(--color-contrast-surface));
  border-color: color-mix(in srgb, var(--color-accent) 82%, var(--color-contrast-surface));
}

.btn-ghost {
  border-color: var(--color-line);
  border-style: dotted;
  color: var(--color-ink);
}

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

.btn-quiet {
  padding: 4px 0;
  color: var(--color-accent);
  border-bottom: var(--border-thin) dotted color-mix(in srgb, var(--color-accent) 45%, transparent);
}

.btn-quiet:hover { border-bottom-style: solid; }

.chip {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 6px var(--space-2);
  background: transparent;
  border: var(--border-thin) dotted var(--color-line);
  border-radius: var(--radius-sm);
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: background-color 0.24s ease-out, color 0.24s ease-out, border-color 0.24s ease-out;
}

.chip:hover { color: var(--color-ink); border-color: var(--color-primary); }

.chip.is-current,
.chip[aria-pressed="true"] {
  background: var(--color-primary-soft);
  color: var(--color-accent);
  border-color: color-mix(in srgb, var(--color-accent) 40%, transparent);
}

/* ---------------------------------------------------------------
   6. 面包屑
   --------------------------------------------------------------- */
.breadcrumb {
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
  list-style: none;
}

.breadcrumb-item { display: inline-flex; align-items: center; gap: var(--space-2); }

.breadcrumb-sep {
  color: var(--color-line);
  letter-spacing: 0.2em;
}

.breadcrumb-link {
  color: var(--color-ink-soft);
  border-bottom: var(--border-thin) dotted var(--color-line);
}

.breadcrumb-link:hover {
  color: var(--color-ink);
  border-bottom-color: var(--color-primary);
}

.breadcrumb-current { color: var(--color-ink); }

/* ---------------------------------------------------------------
   7. 图片容器（图录式统一裁切 + 展签 + 遮罩）
   --------------------------------------------------------------- */
.plate { display: block; }

.plate-media {
  position: relative;
  aspect-ratio: 3 / 2;
  overflow: hidden;
  background: var(--color-surface-deep);
}

.plate--wide .plate-media { aspect-ratio: 16 / 9; }
.plate--tall .plate-media { aspect-ratio: 4 / 5; }
.plate--square .plate-media { aspect-ratio: 1 / 1; }

.plate-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.plate-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: flex-end;
  padding: var(--space-4);
  background: var(--overlay-scrim);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  line-height: 1.6;
}

.plate-caption {
  margin: 0;
  margin-top: var(--space-2);
  padding-top: var(--space-2);
  border-top: var(--border-thin) dotted var(--color-line);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  max-width: calc(var(--measure) / 2);
}

/* ---------------------------------------------------------------
   8. 长内容辅助：章节目录与返回顶部
   --------------------------------------------------------------- */
.chapter-rail {
  position: fixed;
  left: var(--space-4);
  top: 50%;
  transform: translateY(-50%);
  z-index: 40;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding-left: var(--space-2);
  border-left: var(--border-thin) dotted var(--color-line);
}

.chapter-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
  transition: color 0.24s ease-out;
}

.chapter-link:hover { color: var(--color-ink); }

.chapter-link[aria-current="true"] { color: var(--color-accent); }

.chapter-link[aria-current="true"]::before {
  content: "";
  width: 12px;
  border-top: var(--border-thin) solid var(--color-accent);
}

.to-top {
  position: fixed;
  right: var(--space-4);
  bottom: var(--space-4);
  z-index: 50;
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 10px var(--space-3);
  border: 0;
  border-radius: var(--radius-sm);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  letter-spacing: 0.14em;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.28s ease-out, visibility 0.28s ease-out;
}

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

/* ---------------------------------------------------------------
   9. 动效：安静显影
   --------------------------------------------------------------- */
[data-motion="on"] .reveal {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.3s ease-out, transform 0.3s ease-out;
}

[data-motion="on"] .reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* ---------------------------------------------------------------
   10. 页头：居中刊头 + 其下横向栏目
   --------------------------------------------------------------- */
.site-header {
  background: var(--color-surface);
}

.masthead {
  padding-block: var(--space-6) var(--space-4);
}

.masthead-inner {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: end;
  gap: var(--space-4);
}

.masthead-kicker {
  margin: 0;
  justify-self: start;
  font-size: var(--text-xs);
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.masthead-brand {
  grid-column: 2;
  display: block;
  text-align: center;
}

.masthead-title {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  line-height: 1.1;
  letter-spacing: 0.1em;
  color: var(--color-primary);
}

.masthead-tagline {
  display: block;
  margin-top: var(--space-1);
  font-size: var(--text-sm);
  letter-spacing: 0.2em;
  color: var(--color-ink-muted);
}

.masthead-utility {
  justify-self: end;
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--text-sm);
}

.season-tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  color: var(--color-ink-soft);
  letter-spacing: 0.1em;
}

.season-tag::before {
  content: "";
  width: 6px;
  height: 6px;
  background: var(--color-accent);
}

.utility-link {
  color: var(--color-ink);
  letter-spacing: 0.1em;
  border-bottom: var(--border-thin) dotted var(--color-line);
  padding-bottom: 2px;
}

.utility-link:hover {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}

.nav-bar {
  border-top: var(--border-thin) dotted var(--color-line);
  border-bottom: var(--border-thin) dotted var(--color-line);
}

.nav-bar-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-2);
  padding: 10px var(--space-2);
  background: transparent;
  border: var(--border-thin) dotted var(--color-line);
  border-radius: var(--radius-sm);
  color: var(--color-ink);
  font-size: var(--text-sm);
  letter-spacing: 0.14em;
  cursor: pointer;
}

.nav-toggle-bars {
  position: relative;
  display: block;
  width: 18px;
  height: 1px;
  background: currentColor;
}

.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 1px;
  background: currentColor;
  transition: transform 0.24s ease-out, opacity 0.24s ease-out;
}

.nav-toggle-bars::before { top: -5px; }
.nav-toggle-bars::after { top: 5px; }

.nav-toggle[aria-expanded="true"] .nav-toggle-bars { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::before { transform: translateY(5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::after { transform: translateY(-5px) rotate(-45deg); }

.site-nav { display: block; }

.nav-list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-2) var(--space-4);
  list-style: none;
}

.nav-link {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding: var(--space-3) 0;
  color: var(--color-primary);
}

.nav-link-zh {
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  white-space: nowrap;
}

.nav-link-en {
  font-size: var(--text-xs);
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.nav-link:hover { color: var(--color-ink); }
.nav-link:hover .nav-link-en { color: var(--color-ink-soft); }

.nav-link[aria-current="page"] { color: var(--color-ink); }

.nav-link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: var(--space-2);
  border-top: var(--border-thin) dotted var(--color-accent);
}

/* ---------------------------------------------------------------
   11. 页脚：反色区块
   --------------------------------------------------------------- */
.site-footer {
  margin-top: var(--section-y);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.footer-inner {
  padding-block: var(--space-8) var(--space-6);
}

.footer-masthead {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-3);
  padding-bottom: var(--space-6);
  border-bottom: var(--border-thin) dashed var(--color-contrast-line);
}

.footer-brand {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  letter-spacing: 0.12em;
  color: var(--color-contrast-ink);
}

.footer-tagline {
  margin: 0;
  font-size: var(--text-sm);
  letter-spacing: 0.16em;
  color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--gutter);
  padding-block: var(--space-6);
}

.footer-col { min-width: 0; }

.footer-col-title {
  margin: 0 0 var(--space-3);
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: var(--weight-body);
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: color-mix(in srgb, var(--color-contrast-ink) 58%, transparent);
}

.footer-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  list-style: none;
  font-size: var(--text-sm);
  line-height: 1.6;
}

.footer-list a {
  color: var(--color-contrast-ink);
  border-bottom: var(--border-thin) dotted transparent;
  transition: color 0.24s ease-out, border-color 0.24s ease-out;
}

.footer-list a:hover {
  color: var(--color-contrast-accent);
  border-bottom-color: var(--color-contrast-accent);
}

.footer-contact { gap: var(--space-3); }

.contact-key {
  display: block;
  font-size: var(--text-xs);
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: color-mix(in srgb, var(--color-contrast-ink) 52%, transparent);
}

.contact-value {
  display: block;
  font-family: var(--font-mono);
  letter-spacing: 0.01em;
  color: var(--color-contrast-ink);
  word-break: break-word;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2);
  padding-top: var(--space-4);
  border-top: var(--border-thin) dotted var(--color-contrast-line);
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent);
}

.footer-copy,
.footer-legal { margin: 0; letter-spacing: 0.08em; }

/* ---------------------------------------------------------------
   12. 响应式
   --------------------------------------------------------------- */
@media (max-width: 1100px) {
  .nav-list { gap: var(--space-2) var(--space-3); }
}

@media (max-width: 900px) {
  :root { --gutter: 24px; }

  .container { padding-inline: var(--space-3); }

  .section { padding-block: var(--space-8); }
  .section-lg { padding-block: var(--space-8); }

  .span-3, .span-4, .span-5, .span-6,
  .span-7, .span-8, .span-9 { grid-column: span 12; }

  .masthead { padding-block: var(--space-4); }

  .masthead-inner {
    grid-template-columns: 1fr;
    justify-items: center;
    align-items: center;
    gap: var(--space-2);
    text-align: center;
  }

  .masthead-kicker { justify-self: center; }
  .masthead-brand { grid-column: 1; }
  .masthead-title { font-size: var(--text-lg); }
  .masthead-utility { justify-self: center; }

  .nav-bar-inner { justify-content: space-between; padding-block: var(--space-2); }

  .nav-toggle { display: inline-flex; margin-left: auto; }

  .site-nav {
    display: none;
    flex-basis: 100%;
    width: 100%;
    padding-bottom: var(--space-2);
  }

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

  .nav-list { flex-direction: column; gap: 0; }

  .nav-item { border-top: var(--border-thin) dotted var(--color-line); }

  .nav-link {
    flex-direction: row;
    align-items: baseline;
    justify-content: space-between;
    gap: var(--space-2);
    padding: var(--space-3) 0;
  }

  .nav-link-zh { white-space: normal; }

  .nav-link[aria-current="page"]::after {
    left: 0;
    right: auto;
    width: 48px;
    bottom: 0;
  }

  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-inner { padding-block: var(--space-6) var(--space-4); }
  .to-top { right: var(--space-3); bottom: var(--space-3); }
}

@media (max-width: 560px) {
  .footer-grid { grid-template-columns: 1fr; }
  .lede { font-size: calc(var(--text-base) * 1.15); }
  .chapter-rail { display: none; }
}

@media (max-width: 1320px) {
  .chapter-rail { display: none; }
}

/* ---------------------------------------------------------------
   13. 减弱动效
   --------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

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

  [data-motion="on"] .reveal {
    opacity: 1;
    transform: none;
  }
}