/* ==========================================================================
   博喜体育 · boxi-sprint.com.cn
   /assets/site.css — 共享外壳与通用组件
   深夜球场灯光下的数据指挥室 / 可操控战术板
   ========================================================================== */

/* 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, figure, blockquote, dl, dd { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img, svg, video { display: block; max-width: 100%; height: auto; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
a { color: inherit; text-decoration: none; }
table { border-collapse: collapse; width: 100%; }

/* 2. Tokens --------------------------------------------------------------- */
:root {
  /* 品牌色板 */
  --deep:      #06231E;
  --board:     #0B3A31;
  --cyan:      #35F2C0;
  --mint:      #CFFBF0;
  --penalty:   #FF4B2B;
  --corner:    #FFB03A;
  --archive:   #2A2A6E;
  --heritage:  #7A1F3D;
  --paper:     #F4F6F1;
  --ink:       #0A0C0B;
  --gauge:     #8FA6A0;

  /* 边界与遮罩 */
  --line:      rgba(53, 242, 192, 0.20);
  --line-soft: rgba(143, 166, 160, 0.28);
  --line-ink:  rgba(10, 12, 11, 0.14);
  --veil:      rgba(6, 35, 30, 0.62);
  --veil-2:    rgba(11, 58, 49, 0.60);

  /* 字体 */
  --font-display: "Source Han Sans SC", "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", "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  /* 尺度 */
  --header-h: 74px;
  --shell: 1440px;
  --gutter: 2.5rem;
  --ease: cubic-bezier(0.22, 0.8, 0.24, 1);
}

/* 3. 基础排版 ------------------------------------------------------------- */
body {
  background-color: var(--deep);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  letter-spacing: 0.01em;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body.nav-open { overflow: hidden; }

@media (max-width: 640px) {
  body { font-size: 15px; line-height: 1.7; }
}

h1, h2, h3, h4 { font-weight: 300; line-height: 1.15; }

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

:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

/* 4. 工具与布局 ----------------------------------------------------------- */
.container {
  width: min(var(--shell), calc(100% - var(--gutter)));
  margin-inline: auto;
}

.page-top { padding-top: calc(var(--header-h) + clamp(1.5rem, 4vw, 3rem)); }

.section { padding-block: clamp(3.5rem, 9vw, 7.5rem); }
.section--tight { padding-block: clamp(2rem, 5vw, 3.5rem); }

.surface-paper { background-color: var(--paper); color: var(--ink); }
.surface-paper .index { color: #4A5C58; }
.surface-paper .eyebrow { color: #0F6B57; }
.surface-paper .eyebrow::before { background-color: #0F6B57; }
.surface-paper .rule { background-color: var(--line-ink); }

.rule {
  height: 1px;
  border: 0;
  background-color: var(--line-soft);
  margin-block: 2rem;
}

.index {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--gauge);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cyan);
}
.eyebrow::before {
  content: "";
  display: block;
  width: 28px;
  height: 1px;
  background-color: currentColor;
}

.display {
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(2.5rem, 7.6vw, 6.75rem);
  line-height: 0.95;
  letter-spacing: -0.02em;
  color: inherit;
}
.display--sm {
  font-size: clamp(1.9rem, 4.4vw, 3.4rem);
  line-height: 1.06;
  letter-spacing: -0.015em;
}

.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
  font-weight: 500;
}
.num--accent  { color: var(--cyan); }
.num--penalty { color: var(--penalty); }
.num--corner  { color: var(--corner); }

.lede {
  font-size: clamp(1.02rem, 1.5vw, 1.18rem);
  line-height: 1.85;
  color: var(--mint);
  max-width: 62ch;
}
.surface-paper .lede { color: #2C3A36; }

.prose { max-width: 72ch; }
.prose > * + * { margin-top: 1.2em; }
.prose p { line-height: 1.85; }
.prose a {
  color: inherit;
  text-decoration: underline;
  text-decoration-color: var(--cyan);
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}
.prose a:hover { color: var(--cyan); }
.surface-paper .prose a:hover { color: #0F6B57; }
.prose h2 {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(1.6rem, 3vw, 2.35rem);
  line-height: 1.2;
  letter-spacing: -0.015em;
  margin-top: 2.2em;
}
.prose h3 {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(1.15rem, 2vw, 1.45rem);
  margin-top: 1.8em;
}
.prose ul > li {
  position: relative;
  padding-left: 1.35rem;
  margin-top: 0.5em;
  line-height: 1.8;
}
.prose ul > li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.78em;
  width: 10px;
  height: 1px;
  background-color: var(--cyan);
}
.surface-paper .prose ul > li::before { background-color: #0F6B57; }
.prose blockquote {
  border-left: 2px solid var(--cyan);
  padding-left: 1.25rem;
  color: var(--mint);
}

/* 网格 */
.grid { display: grid; gap: clamp(1rem, 2.4vw, 2rem); }
.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)); }
.grid--12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }

@media (max-width: 1024px) {
  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 640px) {
  .grid--2, .grid--3, .grid--4, .grid--12 { grid-template-columns: minmax(0, 1fr); }
}

/* 5. 按钮 ----------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.85rem 1.5rem;
  font-family: var(--font-body);
  font-size: 14px;
  letter-spacing: 0.08em;
  line-height: 1.2;
  background-color: var(--cyan);
  color: var(--ink);
  border: 1px solid var(--cyan);
  clip-path: polygon(0 0, calc(100% - 12px) 0, 100% 100%, 12px 100%);
  transition: transform 0.25s var(--ease), background-color 0.25s var(--ease),
              color 0.25s var(--ease), border-color 0.25s var(--ease);
}
.btn:hover { transform: translateY(-2px); }
.btn:focus-visible { outline-offset: 4px; }

.btn--ghost {
  background-color: transparent;
  color: var(--cyan);
  border-color: var(--cyan);
}
.btn--ghost:hover { background-color: rgba(53, 242, 192, 0.12); }

.btn--penalty {
  background-color: var(--penalty);
  color: #FFFFFF;
  border-color: var(--penalty);
}

/* 6. 标签与面板 ----------------------------------------------------------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.28rem 0.6rem;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  line-height: 1.4;
  color: var(--gauge);
  background-color: rgba(143, 166, 160, 0.08);
  border: 1px solid currentColor;
}
.tag--cyan     { color: var(--cyan);    background-color: rgba(53, 242, 192, 0.10); }
.tag--corner   { color: var(--corner);  background-color: rgba(255, 176, 58, 0.10); }
.tag--penalty  { color: var(--penalty); background-color: rgba(255, 75, 43, 0.10); }
.tag--archive  { color: #9EA6FF;        background-color: rgba(42, 42, 110, 0.35); }
.tag--heritage { color: #F2A0B8;        background-color: rgba(122, 31, 61, 0.35); }

.panel {
  position: relative;
  padding: clamp(1.1rem, 2.4vw, 1.9rem);
  background-color: var(--veil-2);
  border: 1px solid var(--line-soft);
  color: inherit;
}
.panel::before {
  content: "";
  position: absolute;
  top: -1px;
  left: -1px;
  width: 16px;
  height: 16px;
  border-top: 2px solid var(--cyan);
  border-left: 2px solid var(--cyan);
  pointer-events: none;
}
.panel--board {
  background-color: var(--board);
  border-color: var(--line);
}
.panel--paper {
  background-color: var(--paper);
  color: var(--ink);
  border-color: var(--line-ink);
}
.panel--paper::before { border-color: #0F6B57; }
.panel--archive {
  background-color: var(--archive);
  color: #EAEAF7;
  border-color: rgba(255, 255, 255, 0.18);
}
.panel--archive::before { border-color: #9EA6FF; }
.panel--heritage {
  background-color: var(--heritage);
  color: #FBE9EE;
  border-color: rgba(255, 255, 255, 0.18);
}
.panel--heritage::before { border-color: #F2A0B8; }

/* 7. 图片容器基础 --------------------------------------------------------- */
.figure {
  position: relative;
  margin: 0;
  overflow: hidden;
  background-color: var(--board);
  border: 1px solid var(--line-soft);
}
.figure__media {
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background-image:
    repeating-linear-gradient(112deg, rgba(53, 242, 192, 0.07) 0 1px, transparent 1px 18px),
    linear-gradient(152deg, #0B3A31 0%, #06231E 100%);
}
.figure__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  filter: saturate(0.94) contrast(1.05);
}
.figure__caption {
  padding: 0.75rem 1rem;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  line-height: 1.6;
  color: var(--mint);
  background-color: rgba(6, 35, 30, 0.72);
  border-top: 1px solid var(--line-soft);
}
.figure--square .figure__media { aspect-ratio: 1 / 1; }
.figure--tall .figure__media { aspect-ratio: 3 / 4; }

/* 8. 面包屑 --------------------------------------------------------------- */
.breadcrumbs { margin-bottom: 1.5rem; }
.breadcrumbs__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--gauge);
}
.breadcrumbs__item { display: inline-flex; align-items: center; gap: 0.5rem; }
.breadcrumbs__item + .breadcrumbs__item::before {
  content: "/";
  opacity: 0.55;
}
.breadcrumbs__link { transition: color 0.22s var(--ease); }
.breadcrumbs__link:hover { color: var(--cyan); }

/* 9. 隐藏与跳转 ----------------------------------------------------------- */
.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  top: 0.5rem;
  left: 0.5rem;
  z-index: 200;
  padding: 0.7rem 1.1rem;
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--ink);
  background-color: var(--cyan);
  transform: translateY(-180%);
  transition: transform 0.25s var(--ease);
}
.skip-link:focus { transform: translateY(0); }

/* 10. 页头 ---------------------------------------------------------------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 120;
  background-image: linear-gradient(
    180deg,
    rgba(6, 35, 30, 0.94) 0%,
    rgba(6, 35, 30, 0.66) 62%,
    rgba(6, 35, 30, 0) 100%
  );
  border-bottom: 1px solid transparent;
  transition: background-color 0.35s var(--ease), border-color 0.35s var(--ease),
              backdrop-filter 0.35s var(--ease);
}

.site-header[data-solid],
.site-header[data-nav-open] {
  background-color: rgba(6, 35, 30, 0.97);
  background-image: none;
  border-bottom-color: var(--line);
  backdrop-filter: blur(14px) saturate(140%);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
}

.header-inner {
  width: min(var(--shell), calc(100% - var(--gutter)));
  margin-inline: auto;
  min-height: var(--header-h);
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: clamp(0.75rem, 2vw, 2rem);
  padding-block: 0.7rem;
}

/* 品牌 */
.brand {
  grid-column: 1;
  display: flex;
  flex-direction: column;
  gap: 0.14rem;
  position: relative;
  z-index: 2;
}
.brand__mark {
  display: inline-block;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: 1.3rem;
  line-height: 1;
  letter-spacing: 0.06em;
  color: var(--paper);
}
.brand__mark::after {
  content: "";
  display: block;
  height: 2px;
  margin-top: 0.4rem;
  background-image: linear-gradient(90deg, var(--cyan) 0%, rgba(53, 242, 192, 0) 100%);
}
.brand__season {
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--gauge);
}

/* 主导航 */
.site-nav { grid-column: 2; justify-self: center; }
.site-nav__list {
  display: flex;
  align-items: center;
  gap: clamp(0.35rem, 1.5vw, 1.5rem);
}
.site-nav__item { transition: transform 0.3s var(--ease); }
.site-nav__link {
  position: relative;
  display: inline-block;
  padding: 0.5rem 0.25rem;
  font-size: 14px;
  letter-spacing: 0.06em;
  color: var(--mint);
  transition: color 0.25s var(--ease);
}
.site-nav__link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0.24rem;
  height: 1px;
  background-color: var(--cyan);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform 0.3s var(--ease);
}
.site-nav__link:hover { color: var(--cyan); }
.site-nav__link:hover::after { transform: scaleX(1); }
.site-nav__link[aria-current="page"] { color: var(--cyan); }
.site-nav__link[aria-current="page"]::after { transform: scaleX(1); }

@media (min-width: 1100px) {
  .site-nav__item:nth-child(1) { transform: translateY(-5px); }
  .site-nav__item:nth-child(2) { transform: translateY(3px); }
  .site-nav__item:nth-child(3) { transform: translateY(-2px); }
  .site-nav__item:nth-child(4) { transform: translateY(4px); }
  .site-nav__item:nth-child(5) { transform: translateY(-4px); }
  .site-nav__item:nth-child(6) { transform: translateY(2px); }
}

/* 状态条 */
.header-status {
  grid-column: 3;
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.35rem 0.5rem;
}
.status-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.22rem 0.55rem;
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  white-space: nowrap;
  color: var(--mint);
  background-color: rgba(11, 58, 49, 0.6);
  border: 1px solid var(--line-soft);
}
.status-dot {
  flex: none;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background-color: var(--cyan);
  animation: dotPulse 2.6s ease-in-out infinite;
}
.status-chip--pending .status-dot { background-color: var(--corner); }

@keyframes dotPulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50%      { opacity: 0.42; transform: scale(0.72); }
}

/* 滚动进度 */
.scroll-progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  height: 2px;
  width: 100%;
  background-image: linear-gradient(90deg, var(--cyan) 0%, var(--corner) 100%);
  transform: scaleX(0);
  transform-origin: 0 50%;
  pointer-events: none;
}

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 0.55rem;
  padding: 0.55rem 0.75rem;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--mint);
  border: 1px solid var(--line);
  transition: border-color 0.25s var(--ease), color 0.25s var(--ease);
}
.nav-toggle:hover { border-color: var(--cyan); color: var(--cyan); }
.nav-toggle__bars {
  position: relative;
  display: block;
  flex: none;
  width: 18px;
  height: 11px;
}
.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 100%;
  height: 1px;
  background-color: var(--cyan);
  transition: transform 0.3s var(--ease), top 0.3s var(--ease);
}
.nav-toggle__bars::before { top: 0; }
.nav-toggle__bars::after { top: 10px; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { top: 5px; transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { top: 5px; transform: rotate(-45deg); }

@media (max-width: 1150px) {
  .header-status { display: none; }
}

@media (max-width: 900px) {
  .header-inner {
    width: min(var(--shell), calc(100% - 1.5rem));
    grid-template-columns: minmax(0, 1fr) auto;
  }
  .brand { grid-column: 1; }
  .nav-toggle { display: inline-flex; grid-column: 2; justify-self: end; }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    grid-column: auto;
    justify-self: stretch;
    max-height: min(78vh, 640px);
    overflow-y: auto;
    background-color: var(--deep);
    border-top: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
    padding: 1.25rem clamp(1rem, 5vw, 2rem) 1.75rem;
    visibility: hidden;
    opacity: 0;
    transform: translateY(-10px);
    transition: opacity 0.28s var(--ease), transform 0.28s var(--ease), visibility 0.28s linear;
  }
  .site-nav[data-open] {
    visibility: visible;
    opacity: 1;
    transform: translateY(0);
  }
  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }
  .site-nav__item { transform: none; border-bottom: 1px solid rgba(143, 166, 160, 0.16); }
  .site-nav__item:last-child { border-bottom: 0; }
  .site-nav__link {
    display: block;
    padding: 0.95rem 0.2rem;
    font-size: 16px;
    letter-spacing: 0.08em;
  }
  .site-nav__link::after { display: none; }
  .site-nav__link[aria-current="page"]::before {
    content: "";
    position: absolute;
    left: -0.9rem;
    top: 50%;
    width: 6px;
    height: 6px;
    background-color: var(--cyan);
    transform: translateY(-50%) rotate(45deg);
  }
}

/* 11. 页脚 ---------------------------------------------------------------- */
.site-footer {
  position: relative;
  margin-top: clamp(3rem, 7vw, 6rem);
  overflow: hidden;
  color: var(--mint);
  background-image: linear-gradient(158deg, #06231E 0%, #0B3A31 58%, #06231E 100%);
  border-top: 1px solid var(--line);
}
.site-footer::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 5px;
  background-image: repeating-linear-gradient(
    112deg,
    var(--cyan) 0 12px,
    transparent 12px 26px
  );
  opacity: 0.22;
  pointer-events: none;
}
.site-footer::after {
  content: "";
  position: absolute;
  right: -8%;
  top: 14%;
  width: min(38%, 460px);
  aspect-ratio: 1 / 1;
  pointer-events: none;
  background-image:
    radial-gradient(circle at 50% 50%, transparent 0 43%, rgba(53, 242, 192, 0.09) 43% 44%, transparent 44% 100%),
    radial-gradient(circle at 50% 50%, rgba(53, 242, 192, 0.06) 0 28%, transparent 29% 100%);
}

.footer-inner {
  position: relative;
  z-index: 1;
  width: min(var(--shell), calc(100% - var(--gutter)));
  margin-inline: auto;
  padding-top: clamp(2.5rem, 6vw, 4.5rem);
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr) minmax(0, 0.9fr) minmax(0, 1.5fr);
  gap: clamp(1.5rem, 3.5vw, 3.5rem);
  padding-bottom: clamp(2rem, 5vw, 3.5rem);
}

.footer-brand__mark {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--paper);
}
.footer-brand__note {
  max-width: 42ch;
  margin-top: 1rem;
  font-size: 13.5px;
  line-height: 1.9;
  color: var(--mint);
  opacity: 0.82;
}

.footer-col__title {
  padding-bottom: 0.6rem;
  margin-bottom: 1rem;
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 400;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cyan);
  border-bottom: 1px solid rgba(53, 242, 192, 0.2);
}

.footer-list { display: flex; flex-direction: column; gap: 0.6rem; }
.footer-list a {
  display: inline-block;
  font-size: 14px;
  color: var(--mint);
  transition: color 0.22s var(--ease), transform 0.22s var(--ease);
}
.footer-list a:hover { color: var(--cyan); transform: translateX(3px); }

.footer-list--plain li {
  display: flex;
  gap: 0.75rem;
  align-items: baseline;
  font-size: 13.5px;
  line-height: 1.7;
}
.footer-label {
  flex: none;
  min-width: 3.2em;
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--gauge);
}
.footer-value { color: var(--mint); word-break: break-word; }

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem clamp(1rem, 4vw, 2.5rem);
  padding-block: 1.35rem;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--gauge);
  border-top: 1px solid rgba(143, 166, 160, 0.22);
}
.footer-legal__icp { color: var(--mint); letter-spacing: 0.12em; }

@media (max-width: 980px) {
  .footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 2rem 1.5rem;
  }
  .footer-brand { grid-column: 1 / -1; }
}
@media (max-width: 560px) {
  .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .footer-inner { width: min(var(--shell), calc(100% - 1.5rem)); }
}

/* 12. 返回顶部 ------------------------------------------------------------ */
.to-top {
  position: fixed;
  right: clamp(0.75rem, 2vw, 1.75rem);
  bottom: clamp(0.75rem, 2vw, 1.75rem);
  z-index: 110;
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  font-family: var(--font-mono);
  font-size: 16px;
  line-height: 1;
  color: var(--cyan);
  background-color: rgba(6, 35, 30, 0.92);
  border: 1px solid rgba(53, 242, 192, 0.5);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity 0.28s var(--ease), transform 0.28s var(--ease),
              visibility 0.28s linear, background-color 0.22s var(--ease);
}
.to-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.to-top:hover { background-color: rgba(53, 242, 192, 0.16); }

/* 13. 降低动态 ------------------------------------------------------------ */
@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;
    scroll-behavior: auto !important;
  }
  .site-nav { transition: none; }
}