:root {
  --color-surface: #fcfcfc;
  --color-surface-alt: #f3f3f3;
  --color-surface-deep: #e6e7e7;
  --color-ink: #444950;
  --color-ink-soft: #686f79;
  --color-ink-muted: #777f88;
  --color-line: #dbdcdd;
  --color-primary: #4276b8;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #e2e9f2;
  --color-accent: #178087;
  --color-accent-ink: #ffffff;
  --color-highlight: #d3e6e7;
  --color-focus: #0e7e86;
  --color-contrast-surface: #191f26;
  --color-contrast-ink: #e4e5e7;
  --color-contrast-line: #464b50;
  --color-contrast-accent: #25ceda;
  --overlay-scrim: linear-gradient(180deg, rgba(25, 31, 38, 0.35) 0%, rgba(25, 31, 38, 0.72) 55%, rgba(25, 31, 38, 0.92) 100%);
  --font-heading: "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --text-xs: 12.9px;
  --text-sm: 15.5px;
  --text-base: 17px;
  --text-lg: 20.4px;
  --text-xl: 24.5px;
  --text-2xl: 29.4px;
  --text-3xl: 35.3px;
  --text-4xl: 42.3px;
  --text-display: clamp(34px, 6.2vw, 79px);
  --text-figure: clamp(28px, 4.5vw, 57px);
  --weight-heading: 683;
  --weight-body: 400;
  --leading-body: 1.82;
  --leading-heading: 1.22;
  --tracking-heading: -0.006em;
  --radius-sm: 7px;
  --radius-md: 10px;
  --radius-lg: 13px;
  --radius-pill: 999px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: 0 6px 18px rgba(68, 73, 80, 0.08);
  --shadow-2: 0 18px 44px rgba(68, 73, 80, 0.14);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1140px;
  --measure: 67ch;
  --gutter: 16px;
  --section-y: 80px;
  --section-y-lg: 112px;
}

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 128px;
}

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-underline-offset: 0.18em;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 var(--space-2);
  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); }

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

a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

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

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

main [id] { scroll-margin-top: 128px; }

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

/* ========== 布局骨架 ========== */
.wrap {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  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); }

.band { position: relative; z-index: 0; }
.band::before {
  content: "";
  position: absolute;
  z-index: -1;
  inset-block: 0;
  left: calc(50% - 50vw);
  width: 100vw;
  background: var(--band-bg, var(--color-surface-alt));
}
.band--alt { --band-bg: var(--color-surface); }
.band--deep { --band-bg: var(--color-contrast-surface); color: var(--color-contrast-ink); }
.band--deep h2,
.band--deep h3,
.band--deep h4 { color: var(--color-contrast-ink); }
.band--deep p { color: var(--color-contrast-ink); }
.band--deep .meta,
.band--deep .section-head__note { color: color-mix(in srgb, var(--color-contrast-ink) 72%, var(--color-contrast-surface)); }

@media (min-width: 900px) {
  .band--shift-start::before { left: calc(50% - 50vw + 32px); width: calc(100vw - 32px); }
  .band--shift-end::before { width: calc(100vw - 32px); }
}

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

.stack { display: flex; flex-direction: column; gap: var(--space-2); }
.row { display: flex; flex-wrap: wrap; align-items: center; gap: var(--space-2); }
.shift { --shift: 1; }

@media (min-width: 768px) {
  .grid--2 > * { grid-column: span 6; }
  .grid--3 > * { grid-column: span 4; }
  .grid--4 > * { grid-column: span 3; }
  .col-md-3 { grid-column: span 3; }
  .col-md-4 { grid-column: span 4; }
  .col-md-5 { grid-column: span 5; }
  .col-md-6 { grid-column: span 6; }
  .col-md-7 { grid-column: span 7; }
  .col-md-8 { grid-column: span 8; }
  .col-md-9 { grid-column: span 9; }
}

@media (min-width: 1024px) {
  .shift { margin-inline-start: calc(100% / 12 * var(--shift)); }
  .shift--2 { --shift: 2; }
}

.seam { height: var(--border-thin); background: var(--color-line); border: 0; margin: 0; }
.seam--offset { margin-inline-start: var(--space-4); }

/* ========== 刊头 ========== */
.skip-link {
  position: absolute;
  left: var(--space-2);
  top: calc(var(--space-8) * -1);
  z-index: 120;
  padding: var(--space-1) var(--space-2);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  transition: top 0.18s ease;
}
.skip-link:focus { top: var(--space-2); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(252, 252, 252, 0.94);
  background: color-mix(in srgb, var(--color-surface) 94%, transparent);
  border-bottom: var(--border-thin) solid var(--color-line);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  transition: box-shadow 0.18s ease;
}
.site-header[data-scrolled="true"] { box-shadow: var(--shadow-1); }

.site-header__inner { padding-block: var(--space-3) 0; transition: padding 0.18s ease; }

.masthead {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: var(--space-2);
  padding-bottom: var(--space-2);
  transition: padding 0.18s ease;
}
.masthead__brand {
  grid-column: 2;
  justify-self: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  color: var(--color-ink);
}
.masthead__brand:hover { text-decoration: none; }
.masthead__name {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  line-height: 1.1;
  letter-spacing: var(--tracking-heading);
  transition: font-size 0.18s ease;
}
.masthead__sub {
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  letter-spacing: 0.04em;
  transition: opacity 0.18s ease;
}
.cta-link {
  grid-column: 3;
  justify-self: end;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px var(--space-2);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-accent) 34%, var(--color-line));
  border-radius: var(--radius-pill);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-accent);
  white-space: nowrap;
}
.cta-link::after {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: var(--radius-pill);
  background: var(--color-accent);
}
.cta-link:hover {
  text-decoration: none;
  background: color-mix(in srgb, var(--color-accent) 8%, var(--color-surface));
}

.site-header[data-scrolled="true"] .site-header__inner { padding-block: var(--space-1) 0; }
.site-header[data-scrolled="true"] .masthead { padding-bottom: var(--space-1); }
.site-header[data-scrolled="true"] .masthead__name { font-size: var(--text-lg); }
.site-header[data-scrolled="true"] .masthead__sub { opacity: 0; }

.primary-nav { border-top: var(--border-thin) solid var(--color-line); }
.primary-nav__list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-3);
}
.primary-nav__item { display: block; }
.primary-nav__link {
  display: inline-block;
  padding: var(--space-2) 0;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  border-bottom: 2px solid transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}
.primary-nav__link:hover { color: var(--color-ink); text-decoration: none; }
.primary-nav__link[aria-current="page"] {
  color: var(--color-ink);
  font-weight: var(--weight-heading);
  border-bottom-color: var(--color-accent);
}

.nav-toggle { display: none; }
.nav-toggle__bars { position: relative; display: inline-block; width: 14px; height: 10px; }
.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 1.5px;
  background: currentColor;
}
.nav-toggle__bars::before { top: 0; }
.nav-toggle__bars::after { bottom: 0; }
.nav-toggle__text { font-size: var(--text-sm); }

@media (max-width: 859px) {
  .primary-nav {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-1);
  }
  .nav-toggle {
    display: inline-flex;
    align-items: center;
    gap: var(--space-1);
    margin-block: var(--space-1);
    padding: var(--space-1) var(--space-2);
    background: var(--color-surface);
    border: var(--border-thin) solid var(--color-line);
    border-radius: var(--radius-md);
    color: var(--color-ink-soft);
    cursor: pointer;
  }
  .nav-toggle[aria-expanded="true"] {
    color: var(--color-accent);
    border-color: color-mix(in srgb, var(--color-accent) 40%, var(--color-line));
  }
  .primary-nav__list {
    display: none;
    width: 100%;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding-bottom: var(--space-1);
  }
  .primary-nav[data-open] .primary-nav__list { display: flex; }
  .primary-nav[data-open] .primary-nav__link {
    display: block;
    width: 100%;
    padding: var(--space-2) var(--space-1);
    border-bottom: var(--border-thin) solid var(--color-line);
    border-bottom-width: 1px;
  }
  .primary-nav[data-open] .primary-nav__link[aria-current="page"] {
    border-bottom-color: var(--color-line);
    box-shadow: inset 2px 0 0 var(--color-accent);
  }
}

@media (max-width: 639px) {
  .masthead { grid-template-columns: auto 1fr auto; }
  .cta-link { font-size: var(--text-xs); padding: 4px var(--space-1); }
  .cta-link::after { display: none; }
}

/* ========== 页脚 ========== */
.site-footer { margin-top: 0; }

.footer-strip {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-top: var(--border-thin) solid var(--color-contrast-line);
}
.footer-strip__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-1) var(--space-3);
  padding-block: var(--space-3);
}
.footer-strip__brand {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  color: var(--color-contrast-ink);
}
.footer-strip__contact {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
  color: color-mix(in srgb, var(--color-contrast-ink) 78%, var(--color-contrast-surface));
}
.footer-strip__item { display: inline-flex; align-items: center; }
.footer-strip__addr { color: color-mix(in srgb, var(--color-contrast-ink) 62%, var(--color-contrast-surface)); }

.footer-base {
  background: var(--color-surface-alt);
  border-top: var(--border-thin) solid var(--color-line);
}
.footer-base__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-1) var(--space-3);
  padding-block: var(--space-3);
}
.footer-base__brand {
  margin: 0;
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-ink);
}
.footer-base__links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  font-size: var(--text-sm);
}
.footer-base__links a { color: var(--color-ink-soft); }
.footer-base__links a:hover { color: var(--color-primary); }
.footer-base__filing {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

/* ========== 通用组件 ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  min-height: 44px;
  padding: 0 var(--space-3);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  color: var(--color-ink);
  font-size: var(--text-sm);
  font-weight: 500;
  cursor: pointer;
  transition: background 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}
.btn:hover { text-decoration: none; border-color: var(--color-primary); }
.btn--primary {
  background: var(--color-primary);
  color: var(--color-primary-ink);
  border-color: var(--color-primary);
}
.btn--primary:hover {
  background: color-mix(in srgb, var(--color-primary) 86%, var(--color-contrast-surface));
  border-color: color-mix(in srgb, var(--color-primary) 86%, var(--color-contrast-surface));
}
.btn--accent {
  background: var(--color-accent);
  color: var(--color-accent-ink);
  border-color: var(--color-accent);
}
.btn--ghost { background: transparent; }
.btn--onDeep {
  background: transparent;
  color: var(--color-contrast-ink);
  border-color: var(--color-contrast-line);
}
.btn--onDeep:hover {
  border-color: var(--color-contrast-accent);
  color: var(--color-contrast-accent);
}

.arrow-link { font-size: var(--text-sm); font-weight: 500; }
.arrow-link::after { content: "\2192"; margin-left: 6px; }

.crumbs { font-size: var(--text-xs); color: var(--color-ink-muted); }
.crumbs ol { display: flex; flex-wrap: wrap; align-items: center; gap: var(--space-1); }
.crumbs li { display: inline-flex; align-items: center; }
.crumbs li + li::before { content: "/"; margin-right: var(--space-1); color: var(--color-line); }
.crumbs a { color: var(--color-ink-soft); }

.page-head { padding-block: var(--space-8) var(--space-6); }
.display-title {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-display);
  line-height: 1.04;
  letter-spacing: -0.02em;
  margin: 0 0 var(--space-3);
}
.page-title {
  font-size: var(--text-4xl);
  margin: 0 0 var(--space-2);
}
.lede {
  max-width: var(--measure);
  font-size: var(--text-lg);
  color: var(--color-ink-soft);
}

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-1) var(--space-3);
  margin-bottom: var(--space-4);
}
.section-head__title {
  margin: 0;
  font-size: var(--text-2xl);
}
.section-head__note {
  margin: 0;
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.prose { max-width: var(--measure); }
.prose > * + * { margin-top: var(--space-2); }
.prose h2 { font-size: var(--text-2xl); margin-top: var(--space-6); }
.prose h3 { font-size: var(--text-xl); margin-top: var(--space-4); }
.prose ul { list-style: disc; }
.prose ol { list-style: decimal; }
.prose ul,
.prose ol { padding-left: 1.4em; }
.prose li { margin-bottom: var(--space-1); }
.prose blockquote {
  margin: 0;
  padding-left: var(--space-3);
  border-left: 2px solid var(--color-primary);
  color: var(--color-ink-soft);
}

.card {
  padding: var(--space-3);
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
}
.card--raised { box-shadow: var(--shadow-1); }
.card--flat { background: var(--color-surface-alt); border-color: transparent; }
.card__title { font-size: var(--text-lg); margin-bottom: var(--space-1); }
.card__meta {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.meta {
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  letter-spacing: 0.03em;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}
.note { font-size: var(--text-sm); color: var(--color-ink-soft); max-width: var(--measure); }

.tag {
  display: inline-flex;
  align-items: center;
  padding: 2px var(--space-1);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  font-size: var(--text-xs);
  color: var(--color-ink-soft);
}
.tag--accent {
  border-color: color-mix(in srgb, var(--color-accent) 45%, var(--color-line));
  color: var(--color-accent);
}

.mono { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }
.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 500;
}
.figure {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 500;
  line-height: 1;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}
.mark-key {
  padding: 0 4px;
  background: var(--color-highlight);
  border-radius: 3px;
  color: inherit;
}
.roll-digit {
  display: inline-block;
  opacity: 0;
  transform: translateY(0.36em);
  transition: opacity 0.3s ease, transform 0.3s cubic-bezier(0.2, 0.7, 0.3, 1);
  transition-delay: calc(var(--i, 0) * 40ms);
}
.is-in .roll-digit { opacity: 1; transform: none; }

.stat { display: flex; flex-direction: column; gap: var(--space-1); }
.stat__value {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 500;
  line-height: 1;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}
.stat__label { font-size: var(--text-xs); color: var(--color-ink-muted); letter-spacing: 0.05em; }
.band--deep .stat__value { color: var(--color-contrast-accent); }
.band--deep .stat__label { color: color-mix(in srgb, var(--color-contrast-ink) 70%, var(--color-contrast-surface)); }

[data-reveal] { opacity: 0; transition: opacity 0.3s ease; }
[data-reveal].is-in { opacity: 1; }

/* ========== 图形母题：区间 / 频次 / 时段 / 比率 ========== */
.range-band {
  position: relative;
  height: 72px;
  margin-block: var(--space-3) var(--space-4);
}
.range-band__edge {
  position: absolute;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--color-line);
}
.range-band__edge--top { top: 0; }
.range-band__edge--bottom { bottom: 0; }
.range-band__fill {
  position: absolute;
  top: 0;
  bottom: 0;
  left: var(--from, 12%);
  right: var(--to, 24%);
  background: var(--color-primary-soft);
  border-inline: var(--border-thin) solid var(--color-primary);
}
.range-band__label {
  position: absolute;
  bottom: calc(var(--space-2) * -1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}
.range-band__label--start { left: var(--from, 12%); }
.range-band__label--end { right: var(--to, 24%); }

.pulse-bars {
  display: flex;
  align-items: flex-end;
  gap: 6px;
  height: 132px;
}
.pulse-bar {
  position: relative;
  flex: 1 1 0;
  height: var(--level, 50%);
  background: var(--color-surface-deep);
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}
.band--deep .pulse-bar {
  background: color-mix(in srgb, var(--color-contrast-ink) 20%, var(--color-contrast-surface));
}
.pulse-bar__dot {
  position: absolute;
  top: -5px;
  left: 50%;
  transform: translateX(-50%);
  width: 8px;
  height: 8px;
  border-radius: var(--radius-pill);
  background: var(--color-contrast-accent);
  opacity: 0;
  transition: opacity 0.18s ease;
}
.pulse-bar.is-lit .pulse-bar__dot { opacity: 1; }
.pulse-bar__label {
  position: absolute;
  bottom: calc(var(--space-1) * -1.5);
  left: 50%;
  transform: translateX(-50%);
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--color-ink-muted);
}

.time-axis { position: relative; padding-top: var(--space-3); }
.time-axis__rail {
  position: relative;
  display: flex;
  justify-content: space-between;
  gap: var(--space-1);
  height: 30px;
  border-top: var(--border-thin) solid var(--color-line);
}
.time-axis__tick {
  position: relative;
  padding: var(--space-1) 0 0;
  border: 0;
  background: none;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  cursor: pointer;
  text-align: left;
}
.time-axis__tick::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: 1px;
  height: 8px;
  background: var(--color-line);
}
.time-axis__tick[aria-pressed="true"] { color: var(--color-accent); font-weight: 500; }
.time-axis__marker {
  position: absolute;
  top: -6px;
  left: var(--pos, 50%);
  width: 11px;
  height: 11px;
  border-radius: var(--radius-pill);
  background: var(--color-accent);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--color-accent) 16%, transparent);
}
.axis-panel {
  padding-left: var(--space-3);
  border-left: 2px solid var(--color-line);
  transition: background 0.18s ease, border-color 0.18s ease;
}
.axis-panel.is-current {
  border-left-color: var(--color-accent);
  background: var(--color-primary-soft);
}

.ratio-table { border-top: var(--border-thin) solid var(--color-line); }
.ratio-row {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr) auto;
  gap: var(--space-1) var(--space-3);
  align-items: baseline;
  width: 100%;
  padding: var(--space-2) var(--space-1);
  border: 0;
  border-bottom: var(--border-thin) solid var(--color-line);
  background: transparent;
  text-align: left;
  cursor: pointer;
  transition: background 0.18s ease;
}
.ratio-row:hover,
.ratio-row:focus-visible,
.ratio-row.is-active { background: var(--color-primary-soft); }
.ratio-row__tier {
  font-family: var(--font-mono);
  font-weight: 500;
  font-variant-numeric: tabular-nums;
  color: var(--color-ink);
}
.ratio-row__name { font-size: var(--text-sm); color: var(--color-ink); }
.ratio-row__hint {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}
.ratio-row__detail {
  grid-column: 1 / -1;
  display: grid;
  grid-template-rows: 0fr;
  overflow: hidden;
  transition: grid-template-rows 0.18s ease;
}
.ratio-row__detail > div { overflow: hidden; }
.ratio-row__detail p {
  margin: var(--space-1) 0 0;
  max-width: var(--measure);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}
.ratio-row.is-active .ratio-row__detail { grid-template-rows: 1fr; }

/* ========== 目录 / 过滤 / 返回顶部 ========== */
.toc { position: sticky; top: calc(var(--space-8) + var(--space-4)); }
.toc__title {
  margin-bottom: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}
.toc__list { border-left: var(--border-thin) solid var(--color-line); }
.toc__link {
  display: block;
  margin-left: -1px;
  padding: var(--space-1) 0 var(--space-1) var(--space-2);
  border-left: 2px solid transparent;
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  transition: color 0.18s ease, border-color 0.18s ease;
}
.toc__link:hover { color: var(--color-ink); text-decoration: none; }
.toc__link[aria-current="true"] {
  color: var(--color-ink);
  font-weight: 500;
  border-left-color: var(--color-accent);
}

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin-bottom: var(--space-3);
}
.chip {
  padding: 4px var(--space-2);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-pill);
  background: var(--color-surface);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  cursor: pointer;
  transition: background 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}
.chip:hover { border-color: var(--color-primary); color: var(--color-ink); }
.chip[aria-pressed="true"] {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}

.to-top {
  position: fixed;
  right: var(--space-3);
  bottom: var(--space-3);
  z-index: 70;
  padding: var(--space-1) var(--space-2);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  box-shadow: var(--shadow-1);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.18s ease, visibility 0.18s ease;
}
.to-top[data-visible="true"] { opacity: 1; visibility: visible; }

/* ========== 图片容器 ========== */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  background: var(--color-surface-deep);
  border-radius: 0;
}
.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 0;
}
.media-frame--16x9 { aspect-ratio: 16 / 9; }
.media-frame--4x3 { aspect-ratio: 4 / 3; }
.media-frame--1x1 { aspect-ratio: 1 / 1; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--graphic {
  background:
    linear-gradient(135deg,
      color-mix(in srgb, var(--color-primary) 22%, var(--color-surface-deep)) 0%,
      var(--color-surface-deep) 58%,
      color-mix(in srgb, var(--color-accent) 16%, var(--color-surface-deep)) 100%);
}
.media-frame__scrim {
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
}
.media-frame__caption {
  position: absolute;
  inset-inline: var(--space-3);
  bottom: var(--space-3);
  margin: 0;
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
}
.media-frame__tag { position: absolute; top: var(--space-2); left: var(--space-2); }

/* ========== 响应式微调 ========== */
@media (max-width: 859px) {
  .page-head { padding-block: var(--space-6) var(--space-4); }
  .toc { position: static; }
  .pulse-bars { height: 104px; }
}

@media (max-width: 639px) {
  :root { --section-y: 56px; --section-y-lg: 72px; }
  .footer-base__inner,
  .footer-strip__inner { flex-direction: column; align-items: flex-start; }
  .ratio-row { grid-template-columns: 56px minmax(0, 1fr); }
  .ratio-row__hint { grid-column: 2; }
}

/* ========== 动效降级 ========== */
@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-reveal] { opacity: 1; }
  .roll-digit { opacity: 1; transform: none; }
  .pulse-bar__dot { opacity: 1; }
}