/* ============================================================
   四季体育赛场 · /assets/site.css
   共享外壳：reset / design tokens / 中文排版 / 头部 / 页脚 / 基础组件
   ============================================================ */

/* ---------- 1. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

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

ul, ol { list-style: none; }

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

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

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

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

table { border-collapse: collapse; }

/* ---------- 2. Design tokens ---------- */
:root {
  /* 色彩：深场底色 + 珠宝色分区 + 四季强调 */
  --c-ink: #0A1018;
  --c-ink-lift: #0E1520;
  --c-teal: #0F2E2E;
  --c-indigo: #221A47;
  --c-wine: #3A1524;
  --c-spring: #A8E837;
  --c-summer: #FF7A2F;
  --c-autumn: #F2B441;
  --c-winter: #56C8F5;
  --c-paper: #F3F6FA;
  --c-body: #D6DFEA;
  --c-muted: #94A3B8;
  --c-faint: #7F8EA3;
  --c-line: #26313F;
  --c-line-soft: rgba(38, 49, 63, 0.6);

  /* 字体 */
  --font-display: "Archivo Narrow", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", Consolas, "Liberation Mono", monospace;

  /* 字号阶梯 */
  --fs-annotation: 0.75rem;
  --fs-aux: 0.875rem;
  --fs-body: 1rem;
  --fs-sub: 1.375rem;
  --fs-section: 2.125rem;
  --fs-hero: clamp(2.75rem, 7.4vw, 4.5rem);

  /* 布局 */
  --wrap: 1200px;
  --gutter: clamp(18px, 4vw, 40px);
  --header-h: 108px;
  --radius: 2px;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ---------- 3. 基础排版 ---------- */
body {
  min-height: 100vh;
  background: var(--c-ink);
  color: var(--c-body);
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: 1.75;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 800;
  font-stretch: condensed;
  line-height: 1.08;
  letter-spacing: -0.012em;
  color: var(--c-paper);
}

h1 { font-size: var(--fs-hero); }
h2 { font-size: var(--fs-section); }
h3 { font-size: var(--fs-sub); }
h4 { font-size: 1.0625rem; }

html.has-js { scroll-behavior: smooth; }
html.has-nav-open { overflow: hidden; }

:where(a, button, [tabindex], input, textarea, summary):focus-visible {
  outline: 2px solid var(--c-spring);
  outline-offset: 3px;
  border-radius: var(--radius);
}

::selection {
  background: var(--c-spring);
  color: #0A1018;
}

/* ---------- 4. 布局原语 ---------- */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.wrap--narrow { max-width: 860px; }
.wrap--wide { max-width: 1360px; }

.site-main {
  display: block;
  padding-top: var(--header-h);
}

.site-main--flush { padding-top: 0; }

.band {
  position: relative;
  padding-block: clamp(52px, 7vw, 116px);
  overflow: hidden;
}

.band--ink { background: var(--c-ink); }
.band--teal { background: var(--c-teal); }
.band--indigo { background: var(--c-indigo); }
.band--wine { background: var(--c-wine); }

.band--teal::before,
.band--indigo::before,
.band--wine::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.band--teal::before {
  background: radial-gradient(120% 82% at 100% 0%, rgba(86, 200, 245, 0.12), transparent 62%);
}

.band--indigo::before {
  background: radial-gradient(110% 78% at 0% 100%, rgba(168, 232, 55, 0.10), transparent 60%);
}

.band--wine::before {
  background: radial-gradient(120% 80% at 50% 0%, rgba(242, 180, 65, 0.11), transparent 64%);
}

.band > .wrap { position: relative; }

.grid {
  display: grid;
  gap: clamp(18px, 2.4vw, 32px);
}

.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)); }

.flow {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(16px, 2vw, 28px);
}

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

.divider {
  height: 1px;
  border: 0;
  background: var(--c-line);
}

/* ---------- 5. 叙事标记 ---------- */
.section-index {
  display: inline-block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--fs-annotation);
  letter-spacing: 0.2em;
  color: var(--c-winter);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--c-muted);
}

.eyebrow::before {
  content: "";
  width: 24px;
  height: 1px;
  background: currentColor;
  flex: 0 0 auto;
}

.section-title {
  font-size: var(--fs-section);
  margin-top: 14px;
}

.section-lead {
  margin-top: 16px;
  max-width: 44em;
  font-size: 15px;
  color: var(--c-muted);
}

.annotation-vertical {
  writing-mode: vertical-rl;
  text-orientation: mixed;
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  letter-spacing: 0.3em;
  color: var(--c-muted);
}

.stamp {
  display: inline-block;
  transform: rotate(-3deg);
  padding: 4px 10px;
  border: 1px solid currentColor;
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  letter-spacing: 0.14em;
  color: var(--c-autumn);
}

/* ---------- 6. 状态与标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px;
  border: 1px solid currentColor;
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  letter-spacing: 0.08em;
  white-space: nowrap;
}

.tag--spring { color: var(--c-spring); background: rgba(168, 232, 55, 0.10); }
.tag--summer { color: var(--c-summer); background: rgba(255, 122, 47, 0.10); }
.tag--autumn { color: var(--c-autumn); background: rgba(242, 180, 65, 0.10); }
.tag--winter { color: var(--c-winter); background: rgba(86, 200, 245, 0.10); }

.status-dot {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--c-summer);
  flex: 0 0 auto;
}

.status-dot--live { background: var(--c-summer); }

.season-key {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--c-muted);
  white-space: nowrap;
}

.season-key i {
  display: block;
  width: 7px;
  height: 7px;
  border-radius: 1px;
  flex: 0 0 auto;
}

.season-key--spring i { background: var(--c-spring); }
.season-key--summer i { background: var(--c-summer); }
.season-key--autumn i { background: var(--c-autumn); }
.season-key--winter i { background: var(--c-winter); }

/* ---------- 7. 卡片与数据 ---------- */
.print-card {
  position: relative;
  padding: clamp(20px, 2.6vw, 30px);
  background: var(--c-ink-lift);
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  box-shadow: 7px 7px 0 rgba(38, 49, 63, 0.42);
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.stat__value {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(26px, 4vw, 42px);
  line-height: 1;
  letter-spacing: 0.01em;
  color: var(--c-paper);
}

.stat__label {
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  letter-spacing: 0.14em;
  color: var(--c-muted);
}

.stat--spring .stat__value { color: var(--c-spring); }
.stat--summer .stat__value { color: var(--c-summer); }
.stat--autumn .stat__value { color: var(--c-autumn); }
.stat--winter .stat__value { color: var(--c-winter); }

/* ---------- 8. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--c-paper);
  transition: background-color 0.18s var(--ease), color 0.18s var(--ease),
              border-color 0.18s var(--ease), transform 0.18s var(--ease);
}

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

.btn--primary {
  background: var(--c-spring);
  border-color: var(--c-spring);
  color: #0A1018;
}

.btn--primary:hover { background: #BCF25A; }

.btn--live {
  background: var(--c-summer);
  border-color: var(--c-summer);
  color: #170A02;
}

.btn--live:hover { background: #FF8E4D; }

.btn--ghost { background: transparent; }

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

.btn--link {
  padding: 0 0 2px;
  border: 0;
  border-bottom: 1px solid currentColor;
  border-radius: 0;
  color: var(--c-winter);
  font-weight: 500;
}

.btn--link:hover { color: var(--c-spring); }

/* ---------- 9. 面包屑与正文 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--c-muted);
}

.breadcrumb li {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

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

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

.prose {
  max-width: 40em;
  font-size: var(--fs-body);
  line-height: 1.85;
  color: var(--c-body);
}

.prose p + p { margin-top: 1.1em; }
.prose h2 { font-size: var(--fs-sub); margin: 1.9em 0 0.6em; }
.prose h3 { font-size: 1.125rem; margin: 1.6em 0 0.5em; }
.prose strong { color: var(--c-spring); font-weight: 700; }
.prose ul { margin: 1em 0; }

.prose ul li {
  position: relative;
  padding-left: 1.5em;
  margin-top: 0.55em;
}

.prose ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.75em;
  width: 9px;
  height: 2px;
  background: var(--c-autumn);
}

/* ---------- 10. 图片容器基础规则 ---------- */
.media {
  position: relative;
  display: block;
  overflow: hidden;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: linear-gradient(135deg, rgba(15, 46, 46, 0.92), rgba(34, 26, 71, 0.92));
}

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

.media--wide { aspect-ratio: 16 / 9; }
.media--panorama { aspect-ratio: 21 / 9; }
.media--tall { aspect-ratio: 3 / 4; }
.media--square { aspect-ratio: 1 / 1; }

.media--diagonal {
  clip-path: polygon(0 0, 100% 0, 100% 84%, 0 100%);
}

.media__caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 10px 14px;
  background: linear-gradient(0deg, rgba(10, 16, 24, 0.92), rgba(10, 16, 24, 0));
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  letter-spacing: 0.06em;
  color: var(--c-paper);
}

/* ---------- 11. 分段切换 ---------- */
.tabs { margin: 0; }

.tablist {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  border-bottom: 1px solid var(--c-line);
}

.tab {
  position: relative;
  padding: 11px 18px;
  border: 1px solid transparent;
  border-bottom: 0;
  border-radius: var(--radius) var(--radius) 0 0;
  font-family: var(--font-mono);
  font-size: var(--fs-aux);
  letter-spacing: 0.06em;
  color: var(--c-muted);
  transition: color 0.18s var(--ease), background-color 0.18s var(--ease);
}

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

.tab[aria-selected="true"] {
  background: var(--c-winter);
  border-color: var(--c-winter);
  color: #061019;
}

.tabpanel {
  padding-block: clamp(22px, 3vw, 34px);
}

.tabpanel[hidden] { display: none; }

/* ---------- 12. 折叠面板 ---------- */
.accordion { border-top: 1px solid var(--c-line); }

.accordion__item { border-bottom: 1px solid var(--c-line); }

.accordion__trigger {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  width: 100%;
  padding: 20px 0;
  text-align: left;
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--c-paper);
  transition: color 0.18s var(--ease);
}

.accordion__trigger:hover { color: var(--c-autumn); }

.accordion__trigger::after {
  content: "";
  flex: 0 0 auto;
  margin-left: auto;
  margin-top: 0.55em;
  width: 10px;
  height: 10px;
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  transform: rotate(45deg);
  transition: transform 0.22s var(--ease);
}

.accordion__trigger[aria-expanded="true"]::after { transform: rotate(-135deg); }

.accordion__panel {
  max-width: 44em;
  padding-bottom: 22px;
  font-size: 15px;
  color: #C6D1DE;
}

.accordion__panel[hidden] { display: none; }

/* ---------- 13. 时间轴 ---------- */
.timeline {
  display: flex;
  gap: clamp(18px, 3vw, 40px);
  padding: 30px 0 18px;
  border-top: 1px solid var(--c-line);
  overflow-x: auto;
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
}

.timeline__item {
  position: relative;
  flex: 0 0 clamp(210px, 26vw, 300px);
  padding-top: 20px;
  scroll-snap-align: start;
}

.timeline__item::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--c-winter);
}

.timeline__item::after {
  content: "";
  position: absolute;
  top: 4px;
  left: 14px;
  right: -40px;
  height: 1px;
  background: var(--c-line);
}

.timeline__item:last-child::after { display: none; }

/* ---------- 14. 滚动显现 ---------- */
html.has-js .reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.3s var(--ease), transform 0.3s var(--ease);
  transition-delay: var(--reveal-delay, 0ms);
}

html.has-js .reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* ============================================================
   15. 头部
   ============================================================ */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 90;
  background: transparent;
  border-bottom: 1px solid transparent;
  transition: background-color 0.26s var(--ease), border-color 0.26s var(--ease),
              box-shadow 0.26s var(--ease);
}

.site-header.is-solid {
  background: rgba(10, 16, 24, 0.94);
  border-bottom-color: var(--c-line);
  box-shadow: 0 14px 36px rgba(0, 0, 0, 0.44);
}

@supports (backdrop-filter: blur(8px)) {
  .site-header.is-solid {
    background: rgba(10, 16, 24, 0.82);
    backdrop-filter: blur(12px) saturate(1.15);
  }
}

.skip-link {
  position: absolute;
  top: 8px;
  left: var(--gutter);
  z-index: 200;
  padding: 10px 16px;
  border-radius: var(--radius);
  background: var(--c-spring);
  color: #0A1018;
  font-size: var(--fs-aux);
  font-weight: 700;
  transform: translateY(-180%);
  transition: transform 0.18s var(--ease);
}

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

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 2px;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(
    90deg,
    var(--c-spring) 0 25%,
    var(--c-summer) 25% 50%,
    var(--c-autumn) 50% 75%,
    var(--c-winter) 75% 100%
  );
  pointer-events: none;
  z-index: 95;
}

/* 状态细条 */
.status-ribbon {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 7px var(--gutter);
  background: rgba(10, 16, 24, 0.42);
  border-bottom: 1px solid rgba(38, 49, 63, 0.55);
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  letter-spacing: 0.12em;
  color: var(--c-muted);
  white-space: nowrap;
  overflow: hidden;
  transition: padding 0.26s var(--ease), background-color 0.26s var(--ease),
              border-color 0.26s var(--ease), color 0.26s var(--ease);
}

.site-header.is-solid .status-ribbon {
  padding-block: 4px;
  background: transparent;
  border-bottom-color: rgba(38, 49, 63, 0.4);
  color: var(--c-faint);
}

.status-ribbon__pulse {
  flex: 0 0 auto;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--c-spring);
}

.status-ribbon__text { flex: 0 0 auto; }

.status-ribbon__version {
  flex: 0 0 auto;
  color: var(--c-winter);
}

.status-ribbon__seasons {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-left: auto;
  min-width: 0;
  overflow: hidden;
}

/* 品牌与导航 */
.header-bar {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 32px);
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 16px var(--gutter);
  transition: padding 0.26s var(--ease);
}

.site-header.is-solid .header-bar { padding-block: 10px; }

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  padding: 4px 0;
}

.brand__mark {
  display: grid;
  grid-template-columns: repeat(2, 8px);
  grid-template-rows: repeat(2, 8px);
  gap: 3px;
  flex: 0 0 auto;
}

.brand__mark i {
  display: block;
  border-radius: 1px;
}

.brand__mark i:nth-child(1) { background: var(--c-spring); }
.brand__mark i:nth-child(2) { background: var(--c-summer); }
.brand__mark i:nth-child(3) { background: var(--c-autumn); }
.brand__mark i:nth-child(4) { background: var(--c-winter); }

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand__name {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 18px;
  letter-spacing: 0.02em;
  color: var(--c-paper);
}

.brand__tagline {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--c-muted);
}

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

.primary-nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
}

.primary-nav__list a {
  position: relative;
  display: block;
  padding: 10px 12px;
  border-radius: var(--radius);
  font-size: var(--fs-aux);
  letter-spacing: 0.02em;
  color: #CBD6E4;
  transition: color 0.18s var(--ease), background-color 0.18s var(--ease);
}

.primary-nav__list a::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 4px;
  height: 2px;
  background: var(--c-spring);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.22s var(--ease);
}

.primary-nav__list a:hover { color: var(--c-paper); }
.primary-nav__list a:hover::after { transform: scaleX(1); }

.primary-nav__list a[aria-current="page"] { color: var(--c-paper); }

.primary-nav__list a[aria-current="page"]::after {
  transform: scaleX(1);
  background: var(--c-summer);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  margin-left: auto;
  padding: 10px 14px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--c-paper);
  transition: border-color 0.18s var(--ease), color 0.18s var(--ease);
}

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

.nav-toggle__bars {
  position: relative;
  display: block;
  width: 22px;
  height: 2px;
  background: currentColor;
  transition: background-color 0.2s var(--ease);
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 22px;
  height: 2px;
  background: currentColor;
  transition: transform 0.24s var(--ease), top 0.24s var(--ease);
}

.nav-toggle__bars::before { top: -7px; }
.nav-toggle__bars::after { top: 7px; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bars { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { top: 0; transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { top: 0; transform: rotate(-45deg); }

.nav-toggle__label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
}

/* 悬浮胶囊 */
.help-capsule {
  position: fixed;
  right: clamp(16px, 2.2vw, 34px);
  bottom: clamp(18px, 2.6vw, 36px);
  z-index: 88;
  display: flex;
  align-items: center;
  padding: 6px;
  border: 1px solid rgba(168, 232, 55, 0.34);
  border-radius: 999px;
  background: rgba(15, 46, 46, 0.9);
  box-shadow: 0 14px 34px rgba(0, 0, 0, 0.48);
  transition: transform 0.22s var(--ease), border-color 0.22s var(--ease);
}

@supports (backdrop-filter: blur(8px)) {
  .help-capsule {
    background: rgba(15, 46, 46, 0.72);
    backdrop-filter: blur(10px);
  }
}

.help-capsule:hover {
  transform: translateY(-2px);
  border-color: rgba(168, 232, 55, 0.7);
}

.help-capsule__link {
  padding: 9px 16px;
  border-radius: 999px;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--c-paper);
  white-space: nowrap;
  transition: background-color 0.18s var(--ease), color 0.18s var(--ease);
}

.help-capsule__link:hover {
  background: rgba(168, 232, 55, 0.16);
  color: var(--c-spring);
}

.help-capsule__sep {
  width: 1px;
  height: 16px;
  background: rgba(168, 232, 55, 0.28);
}

/* 窄屏底部快捷条 */
.mobile-bar {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 88;
  display: none;
  padding: 6px 4px calc(6px + env(safe-area-inset-bottom, 0px));
  background: rgba(10, 16, 24, 0.96);
  border-top: 1px solid var(--c-line);
}

.mobile-bar__list {
  display: flex;
  align-items: stretch;
  justify-content: space-around;
}

.mobile-bar__list li { flex: 1 1 0; }

.mobile-bar__list a {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 5px;
  padding: 6px 2px;
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--c-muted);
  transition: color 0.18s var(--ease);
}

.mobile-bar__list a:hover,
.mobile-bar__list a:focus-visible { color: var(--c-paper); }

.mobile-bar__dot {
  display: block;
  width: 16px;
  height: 3px;
  border-radius: 2px;
  background: #556274;
}

.mobile-bar__dot--spring { background: var(--c-spring); }
.mobile-bar__dot--summer { background: var(--c-summer); }
.mobile-bar__dot--autumn { background: var(--c-autumn); }
.mobile-bar__dot--winter { background: var(--c-winter); }

/* ============================================================
   16. 页脚
   ============================================================ */
.site-footer {
  position: relative;
  background: #080D14;
  border-top: 1px solid var(--c-line);
  color: var(--c-muted);
  font-size: var(--fs-aux);
}

.footer-legend {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 24px;
  padding-block: 18px;
  border-bottom: 1px solid var(--c-line-soft);
}

.footer-legend__title {
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  letter-spacing: 0.2em;
  color: var(--c-paper);
}

.footer-main {
  display: grid;
  grid-template-columns: minmax(210px, 1.3fr) repeat(3, minmax(110px, 0.85fr)) minmax(210px, 1.2fr);
  gap: clamp(22px, 3vw, 48px);
  padding-block: clamp(36px, 5vw, 64px);
}

.footer-brand__name {
  display: block;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 20px;
  letter-spacing: 0.02em;
  color: var(--c-paper);
}

.footer-brand__tagline {
  margin-top: 10px;
  color: var(--c-muted);
}

.footer-brand__marks {
  display: flex;
  gap: 6px;
  margin-top: 18px;
}

.footer-brand__marks i {
  display: block;
  width: 22px;
  height: 3px;
  border-radius: 2px;
}

.footer-brand__marks i:nth-child(1) { background: var(--c-spring); }
.footer-brand__marks i:nth-child(2) { background: var(--c-summer); }
.footer-brand__marks i:nth-child(3) { background: var(--c-autumn); }
.footer-brand__marks i:nth-child(4) { background: var(--c-winter); }

.footer-col__title {
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  font-weight: 500;
  letter-spacing: 0.18em;
  color: var(--c-winter);
}

.footer-col__list li + li { margin-top: 10px; }

.footer-col__list a {
  color: #C4CFDC;
  transition: color 0.18s var(--ease);
}

.footer-col__list a:hover { color: var(--c-spring); }

.footer-contact__list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  color: #C4CFDC;
  word-break: break-word;
}

.footer-contact__note {
  margin-top: 14px;
  max-width: 32em;
  font-size: var(--fs-annotation);
  line-height: 1.7;
  color: var(--c-faint);
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 24px;
  padding-block: 18px 30px;
  border-top: 1px solid var(--c-line-soft);
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  letter-spacing: 0.05em;
  color: var(--c-faint);
}

.footer-base__meta { color: var(--c-faint); }

/* ============================================================
   17. 响应式
   ============================================================ */
@media (max-width: 1080px) {
  .footer-main { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .span-3, .span-4, .span-5, .span-6 { grid-column: span 6; }
  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 899px) {
  :root { --header-h: 96px; }

  .header-bar { padding-block: 14px; }

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

  .primary-nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    max-height: calc(100vh - var(--header-h));
    margin-left: 0;
    padding: 14px var(--gutter) 30px;
    background: rgba(10, 16, 24, 0.98);
    border-bottom: 1px solid var(--c-line);
    box-shadow: 0 24px 44px rgba(0, 0, 0, 0.52);
    overflow-y: auto;
    transform: translateY(-14px);
    opacity: 0;
    visibility: hidden;
    transition: transform 0.26s var(--ease), opacity 0.26s var(--ease),
                visibility 0.26s var(--ease);
  }

  .primary-nav[data-open="true"] {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

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

  .primary-nav__list a {
    padding: 16px 2px;
    border-bottom: 1px solid rgba(38, 49, 63, 0.7);
    border-radius: 0;
    font-family: var(--font-display);
    font-size: 20px;
    font-weight: 700;
    color: var(--c-paper);
  }

  .primary-nav__list a::after { display: none; }

  .primary-nav__list a[aria-current="page"] { color: var(--c-spring); }

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

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

@media (max-width: 820px) {
  .help-capsule { display: none; }
  .mobile-bar { display: block; }
  body { padding-bottom: 68px; }
  .site-footer { margin-bottom: 0; }
}

@media (max-width: 760px) {
  .status-ribbon__seasons { display: none; }
  .brand__tagline { display: none; }
}

@media (max-width: 620px) {
  .grid--2,
  .grid--3,
  .grid--4 { grid-template-columns: minmax(0, 1fr); }

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

  h2 { font-size: 1.75rem; }

  .section-title { font-size: 1.75rem; }
}

/* ============================================================
   18. 动效偏好
   ============================================================ */
@media (prefers-reduced-motion: no-preference) {
  .status-dot--live { animation: siji-breathe 2.8s ease-in-out infinite; }
  .status-ribbon__pulse { animation: siji-breathe 2.8s ease-in-out infinite; }
}

@keyframes siji-breathe {
  0%, 100% { opacity: 0.5; }
  50% { opacity: 1; }
}

@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;
  }

  html.has-js .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .btn:hover,
  .help-capsule:hover { transform: none; }
}