:root {
  --color-surface: #fefefe;
  --color-surface-alt: #f5f5f5;
  --color-surface-deep: #e7e9e9;
  --color-ink: #424b4d;
  --color-ink-soft: #667275;
  --color-ink-muted: #788487;
  --color-line: #dcdede;
  --color-primary: #248093;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #dfecef;
  --color-accent: #d7288a;
  --color-accent-ink: #ffffff;
  --color-highlight: #f7d7e9;
  --color-focus: #db1a86;
  --color-contrast-surface: #172629;
  --color-contrast-ink: #e4e6e7;
  --color-contrast-line: #445053;
  --color-contrast-accent: #e057a4;
  --overlay-scrim: linear-gradient(180deg, rgba(23, 38, 41, 0.35) 0%, rgba(23, 38, 41, 0.72) 55%, rgba(23, 38, 41, 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: 12.2px;
  --text-sm: 14.6px;
  --text-base: 16px;
  --text-lg: 19.2px;
  --text-xl: 23.0px;
  --text-2xl: 27.6px;
  --text-3xl: 33.2px;
  --text-4xl: 39.8px;
  --text-display: clamp(34px, 4.8vw, 61px);
  --text-figure: clamp(28px, 3.4vw, 44px);
  --weight-heading: 605;
  --weight-body: 400;
  --leading-body: 1.66;
  --leading-heading: 1.28;
  --tracking-heading: 0.003em;
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 7px;
  --radius-pill: 7px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: 0 1px 0 rgba(66, 75, 77, 0.12);
  --shadow-2: 0 2px 0 rgba(66, 75, 77, 0.18);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1180px;
  --measure: 73ch;
  --gutter: 16px;
  --section-y: 76px;
  --section-y-lg: 106px;
}

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 108px;
}

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

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

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

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

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

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

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

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

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

/* ============================================================
   基础排版
   ============================================================ */
body {
  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);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

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

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 { font-size: var(--text-base); }
h6 { font-size: var(--text-sm); }

p {
  max-width: var(--measure);
}

strong,
b {
  font-weight: var(--weight-heading);
}

small {
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

code,
kbd,
samp,
.num,
[data-num] {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum" 1;
}

/* 展示级字号：只用于首屏主标题与大数字 */
.display-title {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: 800;
  line-height: 1.08;
  letter-spacing: -0.01em;
  color: var(--color-ink);
}

.figure-num {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  line-height: 1.05;
  color: var(--color-accent);
}

/* ============================================================
   容器与区块
   ============================================================ */
.shell {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.shell--narrow {
  max-width: 860px;
}

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

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

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

.section--alt { background-color: var(--color-surface-alt); }
.section--deep { background-color: var(--color-surface-deep); }
.section--soft { background-color: var(--color-primary-soft); }
.section--tint { background-color: var(--color-highlight); }

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

.section--contrast h1,
.section--contrast h2,
.section--contrast h3,
.section--contrast h4,
.section--contrast p,
.section--contrast li {
  color: var(--color-contrast-ink);
}

/* ============================================================
   skip link
   ============================================================ */
.skip-link {
  position: fixed;
  left: var(--gutter);
  top: -80px;
  z-index: 300;
  padding: 10px 16px;
  border-radius: var(--radius-md);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  transition: top 120ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.skip-link:focus {
  top: var(--space-1);
}

/* ============================================================
   头部：悬浮胶囊导航
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 90;
  padding-block: var(--space-1);
  isolation: isolate;
}

.site-header::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  background-color: transparent;
  border-bottom: var(--border-thin) solid transparent;
  transition: background-color 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              border-color 200ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.site-header > .shell {
  position: relative;
  z-index: 1;
}

.site-header[data-condensed="true"]::before {
  background-color: var(--color-surface);
  background-color: color-mix(in srgb, var(--color-surface) 90%, transparent);
  border-bottom-color: var(--color-line);
  backdrop-filter: blur(12px) saturate(150%);
  -webkit-backdrop-filter: blur(12px) saturate(150%);
}

.nav-pod {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: 6px 6px 6px var(--space-2);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  background-color: var(--color-surface);
  background-color: color-mix(in srgb, var(--color-surface) 96%, transparent);
  backdrop-filter: blur(12px) saturate(150%);
  -webkit-backdrop-filter: blur(12px) saturate(150%);
  box-shadow: var(--shadow-1);
  transition: box-shadow 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              border-color 200ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.site-header[data-condensed="true"] .nav-pod {
  box-shadow: var(--shadow-2);
  border-color: color-mix(in srgb, var(--color-line) 70%, var(--color-primary));
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
  flex: none;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: none;
  width: 34px;
  height: 34px;
  border-radius: var(--radius-sm);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: 0.02em;
}

.brand-text {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  line-height: 1.25;
  color: var(--color-ink);
  white-space: nowrap;
}

.brand-sub {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.3;
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
  white-space: nowrap;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  margin-left: auto;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 2px;
}

.nav-link {
  display: inline-block;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  color: var(--color-ink-soft);
  white-space: nowrap;
  transition: color 120ms cubic-bezier(0.2, 0.7, 0.2, 1),
              background-color 120ms cubic-bezier(0.2, 0.7, 0.2, 1),
              box-shadow 120ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.nav-link:hover {
  color: var(--color-primary);
  background-color: var(--color-primary-soft);
}

.nav-link[aria-current="page"] {
  color: var(--color-primary);
  background-color: var(--color-primary-soft);
  box-shadow: inset 0 -2px 0 0 var(--color-focus);
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-left: var(--space-1);
  padding: 9px 16px;
  border-radius: var(--radius-md);
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  white-space: nowrap;
  transition: background-color 120ms cubic-bezier(0.2, 0.7, 0.2, 1),
              transform 120ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.nav-cta:hover {
  background-color: color-mix(in srgb, var(--color-accent) 82%, var(--color-contrast-surface));
  transform: translateY(-1px);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  margin-left: auto;
  padding: 8px 12px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
}

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

.nav-toggle-bars {
  display: grid;
  gap: 3px;
  width: 16px;
}

.nav-toggle-bars i {
  display: block;
  height: 2px;
  border-radius: 2px;
  background-color: var(--color-primary);
  transition: transform 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              opacity 200ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.nav-pod[data-open] .nav-toggle-bars i:nth-child(1) {
  transform: translateY(5px) rotate(45deg);
}

.nav-pod[data-open] .nav-toggle-bars i:nth-child(2) {
  opacity: 0;
}

.nav-pod[data-open] .nav-toggle-bars i:nth-child(3) {
  transform: translateY(-5px) rotate(-45deg);
}

/* ============================================================
   页脚：分栏索引 · 浅底深字
   ============================================================ */
.site-footer {
  margin-top: var(--section-y);
  background-color: var(--color-surface-alt);
  border-top: var(--border-thin) solid var(--color-line);
  color: var(--color-ink);
  font-size: var(--text-sm);
}

.footer-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: var(--space-4);
  align-items: end;
  padding-block: var(--space-6) var(--space-3);
}

.footer-brand {
  display: grid;
  gap: 8px;
  max-width: 640px;
}

.footer-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  border: var(--border-thin) solid var(--color-primary);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface);
  color: var(--color-primary);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 700;
}

.footer-title {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
}

.footer-lede {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  max-width: 48ch;
  line-height: 1.6;
}

.footer-scale {
  display: flex;
  gap: 14px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}

.footer-scale li {
  position: relative;
  padding-top: 10px;
}

.footer-scale li::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 1px;
  height: 6px;
  background-color: var(--color-line);
}

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

.footer-col-title {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin-bottom: var(--space-2);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
}

.footer-col-title .idx {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-primary);
}

.footer-list {
  display: grid;
  gap: 10px;
}

.footer-list a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--color-ink-soft);
  transition: color 120ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.footer-list a::before {
  content: "";
  flex: none;
  width: 8px;
  height: 2px;
  border-radius: 1px;
  background-color: var(--color-line);
  transition: background-color 120ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.footer-list a:hover {
  color: var(--color-primary);
}

.footer-list a:hover::before {
  background-color: var(--color-accent);
}

.footer-legal {
  display: grid;
  gap: 8px;
  padding-block: var(--space-3) var(--space-6);
  border-top: var(--border-thin) solid var(--color-line);
  font-size: var(--text-xs);
  line-height: 1.7;
  color: var(--color-ink-muted);
}

.footer-legal p {
  max-width: 92ch;
}

.footer-icp {
  font-family: var(--font-mono);
  letter-spacing: 0.04em;
  color: var(--color-ink-soft);
}

.footer-legal a {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ============================================================
   按钮
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: 10px 18px;
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-md);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  line-height: 1.2;
  letter-spacing: 0.01em;
  cursor: pointer;
  transition: background-color 120ms cubic-bezier(0.2, 0.7, 0.2, 1),
              color 120ms cubic-bezier(0.2, 0.7, 0.2, 1),
              border-color 120ms cubic-bezier(0.2, 0.7, 0.2, 1),
              transform 120ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.btn:hover {
  transform: translateY(-1px);
}

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

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

.btn--accent {
  background-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));
}

.btn--ghost {
  border-color: var(--color-line);
  background-color: var(--color-surface);
  color: var(--color-ink);
}

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

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

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

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

/* ============================================================
   面包屑
   ============================================================ */
.crumbs {
  padding-block: var(--space-2);
}

.crumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.crumb-list li {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.crumb-list li + li::before {
  content: "/";
  color: var(--color-line);
}

.crumb-list a:hover {
  color: var(--color-primary);
}

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

/* ============================================================
   区块题头与编号色标
   ============================================================ */
.section-head {
  display: grid;
  gap: var(--space-2);
  max-width: 860px;
  margin-bottom: var(--space-4);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}

.eyebrow-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 34px;
  height: 20px;
  padding-inline: 6px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface);
  color: var(--color-primary);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
}

.section-title {
  font-size: var(--text-2xl);
}

.section-lede {
  font-size: var(--text-base);
  color: var(--color-ink-soft);
  max-width: 62ch;
}

.section--contrast .section-lede,
.section--contrast .eyebrow {
  color: var(--color-contrast-ink);
}

.section--contrast .eyebrow-index {
  border-color: var(--color-contrast-line);
  background-color: transparent;
  color: var(--color-contrast-accent);
}

.scale-rule {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding-block: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

/* ============================================================
   网格
   ============================================================ */
.grid {
  display: grid;
  gap: var(--space-2);
}

.grid--12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }
.grid--5 { grid-template-columns: repeat(5, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--cards { grid-template-columns: repeat(auto-fill, minmax(248px, 1fr)); gap: var(--space-2); }

/* ============================================================
   卡片与标签
   ============================================================ */
.card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding: var(--space-3);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  background-color: var(--color-surface);
  transition: border-color 120ms cubic-bezier(0.2, 0.7, 0.2, 1),
              box-shadow 120ms cubic-bezier(0.2, 0.7, 0.2, 1),
              transform 120ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-2);
  transform: translateY(-2px);
}

.card--keyed {
  border-left-width: 3px;
}

.card--keyed[data-key="p"] { border-left-color: var(--color-primary); }
.card--keyed[data-key="r"] { border-left-color: var(--color-accent); }
.card--keyed[data-key="s"] { border-left-color: var(--color-contrast-surface); }

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

.card--flat {
  border-radius: var(--radius-sm);
  box-shadow: none;
}

.card--flat:hover {
  transform: none;
  box-shadow: var(--shadow-1);
}

.card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-1);
}

.card-code {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.card-title {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1.3;
  color: var(--color-ink);
}

.card-body {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  line-height: 1.6;
}

.card-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  margin-top: auto;
  padding-top: var(--space-1);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 2px 7px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface-alt);
  color: var(--color-ink-soft);
  font-size: var(--text-xs);
  font-weight: 500;
  line-height: 1.5;
  white-space: nowrap;
}

.tag--primary {
  border-color: transparent;
  background-color: var(--color-primary-soft);
  color: color-mix(in srgb, var(--color-primary) 76%, var(--color-ink));
}

.tag--accent {
  border-color: transparent;
  background-color: var(--color-highlight);
  color: color-mix(in srgb, var(--color-accent) 80%, var(--color-ink));
}

.tag--solid {
  border-color: transparent;
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}

.tag--accent-solid {
  border-color: transparent;
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
}

.tag--contrast {
  border-color: var(--color-contrast-line);
  background-color: transparent;
  color: var(--color-contrast-ink);
}

/* ============================================================
   图片容器
   ============================================================ */
.figure {
  position: relative;
  display: block;
  margin: 0;
  overflow: hidden;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  background-color: var(--color-surface-deep);
}

.figure img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.figure--paper {
  padding: 8px;
  background-color: var(--color-surface-alt);
}

.figure--paper img {
  border-radius: var(--radius-sm);
}

.figure-scrim {
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
  pointer-events: none;
}

.figure-overlay {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: var(--space-3);
  color: var(--color-contrast-ink);
}

.figure-overlay .tag {
  border-color: transparent;
  background-color: var(--color-contrast-accent);
  color: var(--color-accent-ink);
}

.figure-caption {
  margin-top: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.03em;
  color: var(--color-ink-muted);
}

.ratio-16x9 { aspect-ratio: 16 / 9; }
.ratio-4x3 { aspect-ratio: 4 / 3; }
.ratio-1x1 { aspect-ratio: 1 / 1; }

/* ============================================================
   表格
   ============================================================ */
.table-scroll {
  overflow-x: auto;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  background-color: var(--color-surface);
}

.table {
  width: 100%;
  min-width: 640px;
  font-size: var(--text-sm);
}

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

.table thead th {
  position: sticky;
  top: 0;
  z-index: 1;
  background-color: var(--color-surface-deep);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
}

.table tbody tr:hover {
  background-color: var(--color-primary-soft);
}

.table td.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--color-accent);
}

/* ============================================================
   分段切换
   ============================================================ */
.tabs,
[data-tabs] {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  padding: 4px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  background-color: var(--color-surface-alt);
}

.tab {
  padding: 8px 14px;
  border: 0;
  border-radius: var(--radius-sm);
  background: none;
  color: var(--color-ink-soft);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: var(--weight-heading);
  line-height: 1.3;
  cursor: pointer;
  transition: background-color 120ms cubic-bezier(0.2, 0.7, 0.2, 1),
              color 120ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.tab:hover {
  color: var(--color-primary);
}

.tab[aria-selected="true"] {
  background-color: var(--color-surface);
  color: var(--color-primary);
  box-shadow: var(--shadow-1);
}

.tabpanel {
  padding-top: var(--space-3);
}

.tabpanel[hidden] {
  display: none;
}

@keyframes panel-in {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: none; }
}

.tabpanel:not([hidden]) {
  animation: panel-in 240ms cubic-bezier(0.2, 0.7, 0.2, 1) both;
}

/* ============================================================
   显现
   ============================================================ */
html[data-js="on"] [data-reveal] {
  opacity: 0;
  transform: translateY(8px);
}

html[data-js="on"] [data-reveal].is-in {
  opacity: 1;
  transform: none;
  transition: opacity 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
              transform 200ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

/* ============================================================
   焦点与无障碍
   ============================================================ */
:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

.section--contrast :focus-visible {
  outline-color: var(--color-contrast-accent);
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

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

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

  .card:hover,
  .btn:hover,
  .nav-cta:hover {
    transform: none;
  }
}

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 1200px) {
  .nav-link {
    padding-inline: 9px;
  }
}

@media (max-width: 1100px) {
  .brand-sub {
    display: none;
  }
}

@media (max-width: 960px) {
  .nav-toggle {
    display: inline-flex;
  }

  .site-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: calc(100% + 8px);
    z-index: 5;
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-1);
    margin-left: 0;
    padding: var(--space-2);
    border: var(--border-thin) solid var(--color-line);
    border-radius: var(--radius-md);
    background-color: var(--color-surface);
    box-shadow: var(--shadow-2);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-6px);
    transition: opacity 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
                transform 200ms cubic-bezier(0.2, 0.7, 0.2, 1),
                visibility 200ms linear;
  }

  .nav-pod[data-open] .site-nav {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
  }

  .nav-link {
    padding: 10px 12px;
    font-size: var(--text-base);
  }

  .nav-cta {
    justify-content: center;
    margin-left: 0;
    margin-top: var(--space-1);
    padding: 11px 16px;
  }

  .grid--12 {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

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

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

  .footer-scale {
    display: none;
  }

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

@media (max-width: 720px) {
  .section {
    padding-block: var(--space-6);
  }

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

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

  .grid--12 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .card {
    padding: var(--space-2);
  }
}

@media (max-width: 520px) {
  .footer-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .brand-name {
    font-size: var(--text-xs);
  }

  .nav-toggle-text {
    display: none;
  }
}