:root {
  --color-surface: #101110;
  --color-surface-alt: #202221;
  --color-surface-deep: #353736;
  --color-ink: #c7d1cc;
  --color-ink-soft: #86988f;
  --color-ink-muted: #77887f;
  --color-line: #313432;
  --color-primary: #29d67d;
  --color-primary-ink: #111814;
  --color-primary-soft: #142d1f;
  --color-accent: #12ed7d;
  --color-accent-ink: #111814;
  --color-highlight: #103924;
  --color-focus: #06f97c;
  --color-contrast-surface: #f1f3f2;
  --color-contrast-ink: #303633;
  --color-contrast-line: #c7c9c8;
  --color-contrast-accent: #0a8043;
  --overlay-scrim: linear-gradient(180deg, rgba(241, 243, 242, 0.35) 0%, rgba(241, 243, 242, 0.72) 55%, rgba(241, 243, 242, 0.92) 100%);
  --font-heading: ui-monospace, SFMono-Regular, Menlo, Consolas, "PingFang SC", monospace;
  --font-body: "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", 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(45px, 9.3vw, 119px);
  --text-figure: clamp(38px, 6.7vw, 86px);
  --weight-heading: 614;
  --weight-body: 400;
  --leading-body: 1.68;
  --leading-heading: 1.19;
  --tracking-heading: 0.014em;
  --radius-sm: 3px;
  --radius-md: 3px;
  --radius-lg: 3px;
  --radius-pill: 3px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: none;
  --shadow-2: none;
  --space-1: 7px;
  --space-2: 14px;
  --space-3: 21px;
  --space-4: 28px;
  --space-6: 42px;
  --space-8: 56px;
  --container: 1200px;
  --measure: 71ch;
  --gutter: 21px;
  --section-y: 77px;
  --section-y-lg: 108px;
}

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-padding-top: calc(var(--space-1) * 16);
}

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

body {
  margin: 0;
  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;
  text-rendering: optimizeLegibility;
}

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

button {
  font: inherit;
  color: inherit;
}

ul,
ol {
  margin: 0;
  padding: 0;
  list-style: 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-ink);
}

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

p:last-child {
  margin-bottom: 0;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  text-underline-offset: 0.22em;
  transition: color 160ms ease;
}

a:hover {
  color: var(--color-accent);
  text-decoration: underline;
  text-decoration-style: dotted;
}

strong,
b {
  font-weight: 700;
  color: var(--color-ink);
}

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

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

:focus:not(:focus-visible) {
  outline: none;
}

#main-content {
  outline: none;
}

.num,
.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

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

/* ================================================================
   2. 容器与分区节奏
   ================================================================ */
.shell {
  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);
}

.console-layout {
  display: grid;
  grid-template-columns: minmax(0, 3fr) minmax(0, 9fr);
  gap: var(--gutter);
  align-items: start;
}

.console-rail {
  position: sticky;
  top: calc(var(--space-1) * 18);
}

.console-main {
  min-width: 0;
}

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

.dot-rule--strong {
  border-top-color: color-mix(in srgb, var(--color-ink) 34%, transparent);
}

/* ================================================================
   3. 跳转链接
   ================================================================ */
.skip-link {
  position: fixed;
  top: var(--space-2);
  left: var(--space-2);
  z-index: 300;
  padding: var(--space-2) var(--space-3);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transform: translateY(calc(-100% - var(--space-6)));
  transition: transform 180ms ease;
}

.skip-link:hover,
.skip-link:focus {
  color: var(--color-primary-ink);
  text-decoration: none;
}

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

/* ================================================================
   4. 头部
   ================================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 120;
  background-color: transparent;
  border-bottom: var(--border-thin) dotted transparent;
  transition: background-color 200ms ease, border-color 200ms ease;
}

.site-header::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image: linear-gradient(
    180deg,
    color-mix(in srgb, var(--color-surface) 92%, transparent) 0%,
    color-mix(in srgb, var(--color-surface) 60%, transparent) 64%,
    color-mix(in srgb, var(--color-surface) 0%, transparent) 100%
  );
}

.site-header.is-pinned,
.site-header[data-open="true"] {
  background-color: var(--color-surface);
  border-bottom-color: var(--color-line);
}

.site-header.is-pinned::before,
.site-header[data-open="true"]::before {
  background-image: none;
}

.site-header__inner {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--space-4);
  min-height: calc(var(--space-1) * 9);
  padding-block: var(--space-1);
}

/* 品牌 */
.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  flex: 0 0 auto;
  color: var(--color-ink);
  text-decoration: none;
}

.brand:hover,
.brand:focus {
  color: var(--color-ink);
  text-decoration: none;
}

.brand__mark {
  display: grid;
  place-items: center;
  width: calc(var(--space-1) * 5);
  height: calc(var(--space-1) * 5);
  border: var(--border-thin) solid var(--color-primary);
  border-radius: var(--radius-sm);
  background-color: var(--color-primary-soft);
  color: var(--color-primary);
  font-family: var(--font-heading);
  font-size: var(--text-base);
  line-height: 1;
}

.brand__text {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.brand__name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  letter-spacing: var(--tracking-heading);
  line-height: 1.05;
  color: var(--color-ink);
}

.brand__sub {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  line-height: 1.1;
  letter-spacing: 0.1em;
  color: var(--color-ink-soft);
}

/* 主导航 */
.site-nav {
  flex: 1 1 auto;
  min-width: 0;
}

.site-nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  counter-reset: navi;
}

.site-nav__item {
  counter-increment: navi;
}

.site-nav__link {
  display: block;
  padding: var(--space-1) 0;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink-soft);
  text-decoration: none;
  border-bottom: var(--border-thin) dotted transparent;
  transition: color 160ms ease, border-color 160ms ease;
}

.site-nav__link::before {
  content: counter(navi, decimal-leading-zero);
  margin-right: calc(var(--space-1) / 2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.site-nav__link:hover {
  color: var(--color-ink);
  border-bottom-color: var(--color-primary);
  text-decoration: none;
}

.site-nav__link[aria-current="page"] {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.site-nav__link[aria-current="page"]::before {
  color: var(--color-primary);
}

/* 右上角快捷入口 */
.site-header__utility {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex: 0 0 auto;
}

.util-link {
  padding-block: calc(var(--space-1) / 2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-soft);
  text-decoration: none;
  border-bottom: var(--border-thin) dotted var(--color-line);
}

.util-link:hover {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
  text-decoration: none;
}

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  padding: calc(var(--space-1) / 2) var(--space-2);
  background-color: transparent;
  border: var(--border-thin) dotted var(--color-line);
  border-radius: var(--radius-sm);
  color: var(--color-ink);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  cursor: pointer;
  transition: color 160ms ease, border-color 160ms ease;
}

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

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

.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  justify-content: space-between;
  width: 14px;
  height: 11px;
}

.nav-toggle__bars span {
  display: block;
  height: 1px;
  background-color: currentColor;
}

/* 赛季切换常驻条 */
.season-bar {
  border-top: var(--border-thin) dotted var(--color-line);
}

.season-bar__inner {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding-block: calc(var(--space-1) / 2);
}

.season-bar__label {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.18em;
  color: var(--color-ink-muted);
}

.season-bar__list {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
}

.season-bar__list::-webkit-scrollbar {
  display: none;
}

.season-chip {
  display: inline-block;
  padding: calc(var(--space-1) / 2) var(--space-2);
  background-color: transparent;
  border: var(--border-thin) dotted var(--color-line);
  border-radius: var(--radius-sm);
  color: var(--color-ink-soft);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
  white-space: nowrap;
  cursor: pointer;
  transition: color 160ms ease, border-color 160ms ease, background-color 160ms ease;
}

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

.season-chip[aria-pressed="true"] {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  border-style: solid;
  color: var(--color-primary-ink);
}

.season-chip.is-flash {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}

/* 滚动进度 */
.scroll-progress {
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: calc(var(--border-thin) * 2);
  background-color: var(--color-accent);
  transform: scaleX(0);
  transform-origin: 0 50%;
  pointer-events: none;
}

/* ================================================================
   5. 页脚
   ================================================================ */
.site-footer {
  margin-top: var(--section-y-lg);
  background-color: var(--color-surface-deep);
  border-top: var(--border-thin) dotted var(--color-line);
  color: var(--color-ink);
}

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

.site-footer__grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-6);
}

.footer-col {
  padding-left: var(--space-3);
  border-left: var(--border-thin) dotted color-mix(in srgb, var(--color-ink) 30%, transparent);
}

.footer-col__title {
  margin-bottom: var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--weight-heading);
  letter-spacing: 0.18em;
  color: var(--color-primary);
}

.footer-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.footer-list a,
.footer-list span {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
  transition: color 160ms ease;
}

.footer-list a:hover {
  color: var(--color-primary);
  text-decoration: none;
}

.footer-list .num {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-ink);
  word-break: break-all;
}

.footer-note {
  margin-top: var(--space-2);
  font-size: var(--text-xs);
  line-height: 1.6;
  color: var(--color-ink-muted);
}

.site-footer__bottom {
  border-top: var(--border-thin) dotted color-mix(in srgb, var(--color-ink) 30%, transparent);
}

.site-footer__bottom-inner {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding-block: var(--space-3);
}

.site-footer__meta {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}

/* ================================================================
   6. 面包屑与正文容器
   ================================================================ */
.crumbs {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
}

.crumbs__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
}

.crumbs__list li {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
}

.crumbs__list li + li::before {
  content: "/";
  color: var(--color-ink-muted);
}

.crumbs a {
  color: var(--color-ink-soft);
  text-decoration: none;
}

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

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

.prose {
  max-width: var(--measure);
  color: var(--color-ink);
  font-size: var(--text-base);
  line-height: var(--leading-body);
}

.prose h2 {
  margin-top: var(--space-6);
  margin-bottom: var(--space-3);
  font-size: var(--text-2xl);
}

.prose h3 {
  margin-top: var(--space-4);
  margin-bottom: var(--space-2);
  font-size: var(--text-xl);
}

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

.prose ul,
.prose ol {
  margin: 0 0 var(--space-3);
}

.prose ul li {
  position: relative;
  padding-left: var(--space-3);
  margin-bottom: var(--space-1);
}

.prose ul li::before {
  content: "·";
  position: absolute;
  left: var(--space-1);
  color: var(--color-primary);
}

.prose ol {
  counter-reset: proselist;
}

.prose ol li {
  position: relative;
  padding-left: var(--space-4);
  margin-bottom: var(--space-1);
  counter-increment: proselist;
}

.prose ol li::before {
  content: counter(proselist, decimal-leading-zero);
  position: absolute;
  left: 0;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-primary);
}

/* ================================================================
   7. 通用组件
   ================================================================ */
.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.2em;
  color: var(--color-primary);
}

.display {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: 0.94;
  letter-spacing: -0.012em;
  color: var(--color-ink);
}

.figure-value {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: var(--weight-heading);
  line-height: 0.92;
  font-variant-numeric: tabular-nums;
  color: var(--color-primary);
}

.chapter-no {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: var(--weight-heading);
  line-height: 0.85;
  letter-spacing: -0.02em;
  color: color-mix(in srgb, var(--color-primary) 44%, transparent);
}

.status-dot {
  display: inline-block;
  width: var(--space-1);
  height: var(--space-1);
  border-radius: 50%;
  background-color: var(--color-primary);
  flex: 0 0 auto;
}

.status-dot--idle {
  background-color: var(--color-ink-muted);
}

.status-tag {
  display: inline-flex;
  align-items: center;
  gap: calc(var(--space-1) / 2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-primary);
}

/* 键值清单 */
.ledger__row {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  padding: var(--space-2) 0;
  border-bottom: var(--border-thin) dotted var(--color-line);
}

.ledger__key {
  flex: 1 1 auto;
  min-width: 0;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}

.ledger__val {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums;
  color: var(--color-ink);
}

.ledger__row.is-current,
.ledger__row[aria-current="true"] {
  background-color: var(--color-highlight);
}

.ledger__row.is-current .ledger__val,
.ledger__row[aria-current="true"] .ledger__val {
  color: var(--color-primary);
}

/* 索引侧栏 */
.rail-index {
  counter-reset: rail;
}

.rail-index__item {
  counter-increment: rail;
  border-bottom: var(--border-thin) dotted var(--color-line);
}

.rail-index__link {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  padding: var(--space-2) 0;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
  border-left: calc(var(--border-thin) * 2) solid transparent;
  padding-left: var(--space-1);
  transition: color 160ms ease, border-color 160ms ease, background-color 160ms ease;
}

.rail-index__link::before {
  content: counter(rail, decimal-leading-zero);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.rail-index__link:hover {
  color: var(--color-ink);
  text-decoration: none;
  background-color: var(--color-surface-alt);
}

.rail-index__link[aria-current="true"],
.rail-index__link.is-current {
  color: var(--color-primary);
  border-left-color: var(--color-primary);
  background-color: var(--color-primary-soft);
}

/* 可展开内容组 */
.expander {
  border-bottom: var(--border-thin) dotted var(--color-line);
}

.expander__trigger {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  width: 100%;
  padding: var(--space-3) 0;
  background: none;
  border: 0;
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  text-align: left;
  cursor: pointer;
  transition: color 160ms ease;
}

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

.expander__trigger[aria-expanded="true"] {
  color: var(--color-primary);
}

.expander__index {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-primary);
}

.expander__marker {
  margin-left: auto;
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.expander__marker::before {
  content: "+";
}

.expander__trigger[aria-expanded="true"] .expander__marker::before {
  content: "−";
  color: var(--color-primary);
}

.expander__panel {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transition: max-height 300ms ease, opacity 220ms ease;
}

.expander[data-open="true"] .expander__panel {
  opacity: 1;
}

.expander__body {
  max-width: var(--measure);
  padding-bottom: var(--space-4);
  font-size: var(--text-sm);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

/* 图片容器 */
.figure-frame {
  position: relative;
  display: block;
  padding: var(--space-1);
  background-color: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
}

.figure-frame__media {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  background-color: var(--color-surface-deep);
}

.figure-frame__media--wide {
  aspect-ratio: 21 / 9;
}

.figure-frame__media--tall {
  aspect-ratio: 4 / 5;
}

.figure-frame__media > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.58) contrast(1.05) brightness(0.94);
}

.figure-frame__overlay {
  position: absolute;
  inset: 0;
  z-index: 2;
  display: flex;
  align-items: flex-end;
  padding: var(--space-4);
  background-image: var(--overlay-scrim);
  color: var(--color-contrast-ink);
}

.figure-frame__caption {
  margin-top: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}

/* 强对比区 */
.contrast-panel {
  padding: var(--space-6) var(--space-4);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-radius: var(--radius-sm);
}

.contrast-panel h2,
.contrast-panel h3 {
  color: var(--color-contrast-ink);
}

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

.contrast-panel a:hover {
  color: var(--color-contrast-accent);
  text-decoration: underline;
  text-decoration-style: dotted;
}

.contrast-panel .dot-rule,
.contrast-panel hr {
  border-top-color: var(--color-contrast-line);
}

.contrast-panel .ledger__row {
  border-bottom-color: var(--color-contrast-line);
}

.contrast-panel .ledger__key {
  color: var(--color-contrast-ink);
  opacity: 0.72;
}

.contrast-panel .ledger__val {
  color: var(--color-contrast-ink);
}

.contrast-panel .ledger__row.is-current {
  background-color: color-mix(in srgb, var(--color-contrast-accent) 14%, transparent);
}

.contrast-panel .ledger__row.is-current .ledger__val {
  color: var(--color-contrast-accent);
}

.contrast-panel .eyebrow,
.contrast-panel .status-tag {
  color: var(--color-contrast-accent);
}

.contrast-panel .status-dot {
  background-color: var(--color-contrast-accent);
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-4);
  background-color: transparent;
  border: var(--border-thin) solid var(--color-primary);
  border-radius: var(--radius-sm);
  color: var(--color-primary);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.04em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 160ms ease, color 160ms ease, border-color 160ms ease;
}

.btn:hover {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
  text-decoration: none;
}

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

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

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

.btn--quiet:hover {
  background-color: transparent;
  border-color: var(--color-primary);
  border-style: solid;
  color: var(--color-primary);
}

/* 栅格 */
.grid {
  display: grid;
  gap: var(--gutter);
}

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

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

.grid--4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

/* ================================================================
   8. 响应式
   ================================================================ */
@media (max-width: 1080px) {
  .site-footer__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--space-4);
  }
}

@media (max-width: 900px) {
  .console-layout {
    grid-template-columns: 1fr;
  }

  .console-rail {
    position: static;
    order: -1;
  }

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

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

  .site-header__inner {
    flex-wrap: wrap;
    column-gap: var(--space-2);
    padding-bottom: var(--space-2);
  }

  .brand {
    order: 1;
  }

  .nav-toggle {
    order: 2;
    margin-left: auto;
  }

  .site-nav {
    order: 3;
    flex: 0 0 100%;
    display: none;
  }

  .site-header__utility {
    order: 4;
    flex: 0 0 100%;
    display: none;
    flex-wrap: wrap;
    gap: var(--space-3);
    padding-bottom: var(--space-2);
  }

  .site-header[data-open="true"] .site-nav {
    display: block;
    padding-top: var(--space-1);
  }

  .site-header[data-open="true"] .site-header__utility {
    display: flex;
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .site-nav__item {
    border-bottom: var(--border-thin) dotted var(--color-line);
  }

  .site-nav__link {
    padding: var(--space-3) 0;
    font-size: var(--text-base);
    border-bottom: 0;
  }

  .site-nav__link:hover {
    border-bottom-color: transparent;
  }

  .site-nav__link[aria-current="page"] {
    padding-left: var(--space-2);
    border-left: calc(var(--border-thin) * 2) solid var(--color-primary);
    border-bottom-color: transparent;
  }

  .grid--3,
  .grid--4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 640px) {
  .shell {
    padding-inline: var(--space-2);
  }

  .brand__name {
    font-size: var(--text-base);
  }

  .season-bar__label {
    display: none;
  }

  .site-footer__grid {
    grid-template-columns: 1fr;
    gap: var(--space-4);
  }

  .footer-col {
    padding-left: var(--space-2);
  }

  .grid--2,
  .grid--3,
  .grid--4 {
    grid-template-columns: 1fr;
  }

  .contrast-panel {
    padding: var(--space-4) var(--space-3);
  }

  .expander__trigger {
    font-size: var(--text-base);
  }
}

/* ================================================================
   9. 动效降级
   ================================================================ */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}