:root {
  --color-surface: #f5f6f5;
  --color-surface-alt: #ecedec;
  --color-surface-deep: #dfe1df;
  --color-ink: #3c493d;
  --color-ink-soft: #607161;
  --color-ink-muted: #768977;
  --color-line: #d4d7d4;
  --color-primary: #238528;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #d8e6d8;
  --color-accent: #7c12ed;
  --color-accent-ink: #ffffff;
  --color-highlight: #dfcdf4;
  --color-focus: #7c05fa;
  --color-contrast-surface: #111d12;
  --color-contrast-ink: #e4e7e4;
  --color-contrast-line: #3f4940;
  --color-contrast-accent: #a65ef3;
  --overlay-scrim: linear-gradient(180deg, rgba(17, 29, 18, 0.35) 0%, rgba(17, 29, 18, 0.72) 55%, rgba(17, 29, 18, 0.92) 100%);
  --font-heading: "Source Han Serif SC", "Songti SC", Georgia, serif;
  --font-body: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, Menlo, Consolas, monospace;
  --text-xs: 9.5px;
  --text-sm: 13.5px;
  --text-base: 16px;
  --text-lg: 22.6px;
  --text-xl: 32.0px;
  --text-2xl: 45.2px;
  --text-3xl: 64.0px;
  --text-4xl: 90.4px;
  --text-display: clamp(36px, 7.5vw, 96px);
  --text-figure: clamp(30px, 5.4vw, 69px);
  --weight-heading: 797;
  --weight-body: 400;
  --leading-body: 1.68;
  --leading-heading: 1.17;
  --tracking-heading: 0.0em;
  --radius-sm: 2px;
  --radius-md: 2px;
  --radius-lg: 2px;
  --radius-pill: 2px;
  --border-thin: 1px;
  --border-thick: 2px;
  --shadow-1: 0 1px 0 rgba(60, 73, 61, 0.12);
  --shadow-2: 0 2px 0 rgba(60, 73, 61, 0.18);
  --space-1: 6px;
  --space-2: 12px;
  --space-3: 18px;
  --space-4: 24px;
  --space-6: 36px;
  --space-8: 48px;
  --container: 1220px;
  --measure: 70ch;
  --gutter: 18px;
  --section-y: 73px;
  --section-y-lg: 102px;
}

/* ============================================================
   基础重置
   ============================================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
}

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

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

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  color: var(--color-ink);
  background-color: var(--color-surface);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

p,
figure,
blockquote,
dl,
dd {
  margin: 0;
}

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

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

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

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

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

table {
  width: 100%;
  border-collapse: collapse;
}

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

strong,
b {
  font-weight: 700;
}

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

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

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
}

.skip-link {
  position: absolute;
  left: var(--gutter);
  top: -120px;
  z-index: 200;
  display: inline-block;
  padding: var(--space-2) var(--space-4);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-radius: var(--radius-sm);
  transition: top 0.18s ease;
}

.skip-link:focus {
  top: var(--space-2);
}

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

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

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

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

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

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

.stack-2 {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.stack-4 {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

/* ============================================================
   文字角色
   ============================================================ */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 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);
}

.eyebrow::before {
  content: "";
  flex: none;
  width: 16px;
  height: var(--border-thick);
  background-color: var(--color-accent);
}

.annotation {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.7;
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}

.display-title {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: -0.02em;
  color: var(--color-ink);
}

.section-title {
  font-family: var(--font-heading);
  font-size: var(--text-3xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: -0.015em;
}

.figure-value {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  color: var(--color-primary);
}

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

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

.prose {
  max-width: var(--measure);
  color: var(--color-ink);
}

.prose > * + * {
  margin-top: var(--space-4);
}

.prose p {
  margin: 0;
}

.prose h2 {
  margin-top: var(--space-8);
  font-size: var(--text-2xl);
}

.prose h3 {
  margin-top: var(--space-6);
  font-size: var(--text-xl);
}

.prose ul,
.prose ol {
  padding-left: var(--space-6);
  list-style: disc;
}

.prose ol {
  list-style: decimal;
}

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

.prose a {
  color: var(--color-primary);
  border-bottom: var(--border-thin) solid var(--color-primary);
}

.prose a:hover {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}

/* ============================================================
   结构语言
   ============================================================ */
.emph-block {
  position: relative;
  padding-left: var(--space-4);
  border-left: var(--border-thick) solid var(--color-primary);
}

.emph-block--accent {
  border-left-color: var(--color-accent);
}

.rule {
  height: 0;
  margin: var(--space-6) 0;
  border: 0;
  border-top: var(--border-thin) dashed var(--color-line);
}

.rule--dotted {
  border-top-style: dotted;
}

.rule--offset {
  margin-left: calc(100% / 12);
}

.panel {
  position: relative;
  padding: var(--space-6);
  background-color: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
}

.panel--raised {
  box-shadow: var(--shadow-2);
}

.panel--accent {
  border-top: var(--space-1) solid var(--color-accent);
}

.panel--primary {
  border-top: var(--space-1) solid var(--color-primary);
}

.slab {
  position: relative;
  padding: var(--space-6);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-radius: var(--radius-sm);
}

.slab .eyebrow,
.slab .annotation {
  color: var(--color-contrast-ink);
  opacity: 0.78;
}

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

.slab .rule {
  border-top-color: var(--color-contrast-line);
}

.slab--accent {
  border-left: var(--space-1) solid var(--color-contrast-accent);
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 2px var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-primary);
  background-color: var(--color-primary-soft);
  border-radius: var(--radius-sm);
}

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

.chip--muted {
  color: var(--color-ink-muted);
  background-color: var(--color-surface-deep);
}

.axis-rail {
  position: relative;
  margin: 0;
  padding: var(--space-2) 0 var(--space-2) var(--space-6);
  list-style: none;
  border-left: var(--border-thin) dashed var(--color-line);
}

.axis-rail > li {
  position: relative;
  padding-block: var(--space-2);
}

.axis-rail > li::before {
  content: "";
  position: absolute;
  left: calc(var(--space-6) * -1);
  top: 0.95em;
  width: var(--space-3);
  height: var(--border-thick);
  background-color: var(--color-line);
  transform: translateY(-50%);
}

.axis-rail > li.is-current::before {
  width: var(--space-4);
  background-color: var(--color-primary);
}

/* ============================================================
   按钮与操作
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--color-ink);
  background-color: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  transition: background-color 0.16s ease, color 0.16s ease, border-color 0.16s ease, transform 0.16s ease;
}

.btn:hover {
  border-color: var(--color-ink-soft);
  transform: translateY(-1px);
}

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

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

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

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

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

.btn--mono {
  font-family: var(--font-mono);
  letter-spacing: 0.1em;
}

.copy-btn {
  align-self: flex-start;
  padding: var(--space-1) var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-soft);
  background-color: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  transition: background-color 0.16s ease, color 0.16s ease, border-color 0.16s ease;
}

.copy-btn:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

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

/* ============================================================
   面包屑 / 过滤 / 折叠 / 表格
   ============================================================ */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
  padding-block: var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
  list-style: none;
}

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

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

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

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

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

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding-block: var(--space-3);
  border-top: var(--border-thin) dashed var(--color-line);
  border-bottom: var(--border-thin) dashed var(--color-line);
}

.filter-btn {
  padding: var(--space-1) var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-soft);
  background-color: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  transition: background-color 0.16s ease, color 0.16s ease, border-color 0.16s ease;
}

.filter-btn:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

.filter-btn[aria-pressed="true"] {
  color: var(--color-accent-ink);
  background-color: var(--color-accent);
  border-color: var(--color-accent);
}

.accordion {
  border-top: var(--border-thin) solid var(--color-line);
}

.accordion details {
  border-bottom: var(--border-thin) dashed var(--color-line);
}

.accordion summary {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding-block: var(--space-4);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  cursor: pointer;
  list-style: none;
}

.accordion summary::-webkit-details-marker {
  display: none;
}

.accordion summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  font-weight: 400;
  color: var(--color-accent);
}

.accordion details[open] > summary::after {
  content: "–";
}

.accordion .accordion-body {
  padding-bottom: var(--space-6);
}

.table-wrap {
  width: 100%;
  overflow-x: auto;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
}

.table {
  min-width: 560px;
  font-size: var(--text-sm);
}

.table caption {
  padding: var(--space-3);
  text-align: left;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.table th,
.table td {
  padding: var(--space-2) var(--space-3);
  text-align: left;
  border-bottom: var(--border-thin) dotted var(--color-line);
}

.table thead th {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 400;
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
  background-color: var(--color-surface-deep);
  border-bottom: var(--border-thin) solid var(--color-line);
}

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

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

/* ============================================================
   媒体容器（页面阶段投放图片）
   ============================================================ */
.media {
  position: relative;
  display: block;
  overflow: hidden;
  background-color: var(--color-surface-deep);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
}

.media > img,
.media > video {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media--16x9 { aspect-ratio: 16 / 9; }
.media--4x3  { aspect-ratio: 4 / 3; }
.media--3x2  { aspect-ratio: 3 / 2; }
.media--1x1  { aspect-ratio: 1 / 1; }
.media--wide { aspect-ratio: 21 / 9; }

.media-scrim {
  position: absolute;
  inset: 0;
  z-index: 1;
  background: var(--overlay-scrim);
  pointer-events: none;
}

.media-caption {
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 2;
  max-width: 100%;
  padding: var(--space-1) var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.6;
  letter-spacing: 0.06em;
  color: var(--color-contrast-ink);
  background-color: var(--color-contrast-surface);
  border-top-right-radius: var(--radius-sm);
}

/* ============================================================
   显现
   ============================================================ */
.has-js [data-reveal] {
  opacity: 0;
  transform: translateY(10px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.has-js [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

/* ============================================================
   页头
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background-color: var(--color-surface);
  background-color: color-mix(in srgb, var(--color-surface) 94%, transparent);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.reading-track {
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 3px;
  background-color: var(--color-surface-deep);
  overflow: hidden;
}

.reading-fill {
  display: block;
  width: 0;
  height: 100%;
  background-image: linear-gradient(90deg, var(--color-primary) 0%, var(--color-accent) 100%);
}

.header-inner {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--space-4);
  width: 100%;
  max-width: var(--container);
  min-height: 74px;
  margin-inline: auto;
  padding: var(--space-2) var(--gutter);
}

.brand-lockup {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 2px;
  flex: 0 0 auto;
  padding-left: var(--space-3);
}

.brand-lockup::before {
  content: "";
  position: absolute;
  left: 0;
  top: -14px;
  bottom: -14px;
  width: var(--space-1);
  background-color: var(--color-accent);
  border-radius: var(--radius-sm);
}

.brand-index {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
}

.brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--color-ink);
}

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

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

.primary-nav {
  display: flex;
  align-items: center;
  margin-left: var(--space-2);
}

.nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: navstep;
}

.nav-list a {
  display: inline-flex;
  align-items: baseline;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  line-height: 1.2;
  color: var(--color-ink-soft);
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-sm);
  transition: background-color 0.16s ease, color 0.16s ease, border-color 0.16s ease;
}

.nav-list a::before {
  counter-increment: navstep;
  content: counter(navstep, decimal-leading-zero);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  transition: color 0.16s ease, opacity 0.16s ease;
}

.nav-list a:hover {
  color: var(--color-primary);
  background-color: var(--color-primary-soft);
  border-color: var(--color-primary-soft);
}

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

.nav-list a[aria-current="page"] {
  color: var(--color-primary-ink);
  background-color: var(--color-primary);
  border-color: var(--color-primary);
}

.nav-list a[aria-current="page"]::before {
  color: var(--color-primary-ink);
  opacity: 0.72;
}

.header-meta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-left: auto;
  padding-left: var(--space-3);
  border-left: var(--border-thin) dashed var(--color-line);
}

.season-axis {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  white-space: nowrap;
  color: var(--color-ink-muted);
}

.season-axis::before {
  content: "";
  flex: none;
  width: 7px;
  height: 7px;
  background-color: var(--color-primary);
  border-radius: var(--radius-sm);
  animation: axis-pulse 2.8s ease-in-out infinite;
}

.season-axis-label {
  color: var(--color-ink);
}

@keyframes axis-pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.28; }
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-2);
  margin-left: auto;
  padding: var(--space-2) var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink);
  background-color: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-ink);
  border-radius: var(--radius-sm);
}

.nav-toggle-bars {
  position: relative;
  display: block;
  width: 16px;
  height: 10px;
}

.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: var(--border-thick);
  background-color: currentColor;
  transition: transform 0.18s ease;
}

.nav-toggle-bars::before { top: 0; }
.nav-toggle-bars::after { bottom: 0; }

.nav-toggle[aria-expanded="true"] .nav-toggle-bars::before {
  transform: translateY(4px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bars::after {
  transform: translateY(-4px) rotate(-45deg);
}

@keyframes nav-drop {
  from { opacity: 0; transform: translateY(-6px); }
  to { opacity: 1; transform: none; }
}

/* ============================================================
   页脚
   ============================================================ */
.site-footer {
  position: relative;
  margin-top: var(--section-y-lg);
  color: var(--color-ink);
  background-color: var(--color-surface-alt);
}

.site-footer::before {
  content: "";
  display: block;
  height: 6px;
  background-image: repeating-linear-gradient(
    90deg,
    var(--color-surface) 0 1px,
    transparent 1px var(--space-3)
  );
  background-color: var(--color-contrast-surface);
}

.footer-inner {
  position: relative;
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.footer-stamp {
  position: absolute;
  left: 0;
  top: calc(var(--space-2) * -1 - 8px);
  z-index: 2;
  width: 30px;
  height: 30px;
  background-color: var(--color-accent);
  border-radius: var(--radius-sm);
}

.footer-tier {
  position: relative;
  padding-block: var(--space-8);
}

.footer-tier--index {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.5fr) minmax(0, 1fr);
  gap: var(--space-6) var(--space-8);
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding-top: var(--space-2);
}

.footer-brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-2xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: -0.015em;
  color: var(--color-ink);
}

.footer-brand-desc {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.7;
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.footer-index-label {
  padding-bottom: var(--space-2);
  margin-bottom: var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.footer-nav-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 var(--space-6);
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: footstep;
}

.footer-nav-list a {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  padding-block: var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  border-bottom: var(--border-thin) dotted var(--color-line);
  transition: color 0.16s ease, padding-left 0.16s ease;
}

.footer-nav-list a::before {
  counter-increment: footstep;
  content: counter(footstep, decimal-leading-zero);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.footer-nav-list a:hover {
  padding-left: var(--space-1);
  color: var(--color-accent);
}

.footer-contact {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.footer-contact-value {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.02em;
  color: var(--color-ink);
  word-break: break-word;
}

.footer-contact-address,
.footer-contact-note {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.7;
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
}

.footer-tier--legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-6);
  padding-block: var(--space-4) var(--space-6);
  border-top: var(--border-thin) dashed var(--color-line);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.legal-copy {
  color: var(--color-ink-muted);
}

.legal-nav {
  margin-left: auto;
}

.legal-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2) var(--space-4);
  margin: 0;
  padding: 0;
  list-style: none;
}

.legal-list a {
  color: var(--color-ink-soft);
  border-bottom: var(--border-thin) dotted var(--color-line);
}

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

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 1080px) {
  .season-axis-value {
    display: none;
  }
}

@media (max-width: 900px) {
  .header-inner {
    flex-wrap: wrap;
    gap: var(--space-2);
    padding-block: var(--space-2);
  }

  .brand-desc {
    display: none;
  }

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

  .header-meta {
    display: none;
  }

  .primary-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: none;
    margin: 0;
    padding: var(--space-3) var(--gutter) var(--space-4);
    background-color: var(--color-surface);
    border-top: var(--border-thin) solid var(--color-line);
    border-bottom: var(--border-thick) solid var(--color-primary);
    box-shadow: var(--shadow-2);
  }

  .primary-nav[data-open] {
    display: block;
    animation: nav-drop 0.2s ease both;
  }

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

  .nav-list a {
    justify-content: flex-start;
    padding: var(--space-3) var(--space-2);
    font-size: var(--text-base);
    border: 0;
    border-bottom: var(--border-thin) dashed var(--color-line);
    border-radius: 0;
  }

  .nav-list a[aria-current="page"] {
    padding-left: var(--space-3);
    border-bottom-color: var(--color-primary);
  }

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

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

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

  .footer-brand {
    grid-column: 1 / -1;
  }

  .footer-stamp {
    left: var(--gutter);
  }
}

@media (max-width: 640px) {
  .section {
    padding-block: var(--space-8);
  }

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

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

  .col-3, .col-4, .col-5, .col-6, .col-7, .col-8, .col-9 {
    grid-column: span 2;
  }

  .footer-tier--index {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--space-6);
  }

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

  .footer-tier--legal {
    flex-direction: column;
    align-items: flex-start;
  }

  .legal-nav {
    margin-left: 0;
  }

  .rule--offset {
    margin-left: 0;
  }
}

/* ============================================================
   无障碍与动效收敛
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

  .has-js [data-reveal] {
    opacity: 1 !important;
    transform: none !important;
  }

  .season-axis::before {
    animation: none !important;
  }
}