/* =========================================
   第一娱乐站 · 全站共享样式 /assets/site.css
   ========================================= */

/* ---------- 1. 变量 ---------- */
:root {
  --color-ink: #0B0C10;
  --color-gold: #C9A227;
  --color-red: #A6192E;
  --color-yellow: #FFD700;
  --color-ice: #8FB8D8;
  --color-stone: #6B7174;
  --color-moss: #5E6E5E;
  --color-cream: #F5F0E9;
  --font-heading: 'Noto Sans SC', 'Microsoft YaHei', sans-serif;
  --font-body: 'Noto Sans SC', 'Source Han Sans SC', sans-serif;
  --container-w: 1280px;
  --space-1: 0.5rem;
  --space-2: 1rem;
  --space-3: 1.5rem;
  --space-4: 2rem;
  --space-5: 3rem;
  --space-6: 5rem;
  --nav-offset: 56px;
}

/* ---------- 2. Reset ---------- */
*, *::before, *::after {
  box-sizing: border-box;
}
html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}
body {
  margin: 0;
}
body, h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd {
  margin: 0;
}
ul[class], ol[class] {
  padding: 0;
  list-style: none;
}
a {
  color: inherit;
}
button {
  font: inherit;
  cursor: pointer;
}
img, svg {
  max-width: 100%;
  display: block;
}

/* ---------- 3. 基础排版 ---------- */
body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  color: var(--color-cream);
  background-color: var(--color-ink);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 800;
  line-height: 1.25;
  color: var(--color-cream);
}
h1 { font-size: clamp(2.5rem, 6vw, 3.5rem); line-height: 1.15; }
h2 { font-size: clamp(2rem, 5vw, 2.5rem); }
h3 { font-size: clamp(1.25rem, 3vw, 1.75rem); }
p { margin-bottom: 1rem; }
a {
  color: var(--color-gold);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
strong { font-weight: 700; }
small { font-size: 0.875rem; }
[id] { scroll-margin-top: calc(var(--nav-offset) + 1rem); }

/* ---------- 4. 通用容器与章节 ---------- */
.container {
  width: 100%;
  max-width: var(--container-w);
  margin-inline: auto;
  padding-inline: clamp(1.25rem, 4vw, 2.5rem);
}
.main-content {
  min-height: 60vh;
  padding-bottom: var(--space-6);
}
.section {
  padding-block: clamp(3rem, 8vw, 6rem);
}
.section-title {
  display: flex;
  align-items: center;
  gap: 0.9rem;
  font-family: var(--font-heading);
  font-size: clamp(1.5rem, 4vw, 2.25rem);
  font-weight: 800;
  margin-bottom: var(--space-4);
}
.section-title::before {
  content: '';
  flex: 0 0 auto;
  width: 10px;
  height: 10px;
  background: var(--color-gold);
  transform: rotate(45deg);
  box-shadow: 0 0 8px rgba(201, 162, 39, 0.6);
}
.page-title {
  font-size: clamp(2rem, 5vw, 3rem);
  margin-bottom: var(--space-2);
}
.page-subtitle {
  font-size: 1rem;
  line-height: 1.75;
  color: var(--color-stone);
  max-width: 72ch;
}
.prose {
  max-width: 75ch;
  font-size: 1rem;
  line-height: 1.9;
  color: rgba(245, 240, 233, 0.82);
}
.prose p { margin-bottom: 1.25rem; }
.prose h2 {
  font-size: 1.5rem;
  margin-top: var(--space-5);
  margin-bottom: var(--space-2);
}
.prose h3 {
  font-size: 1.15rem;
  margin-top: var(--space-4);
  margin-bottom: var(--space-2);
}
.prose a { color: var(--color-gold); }
.prose ul {
  margin: 0 0 1.25rem 1.25rem;
  padding: 0;
}
.prose li { margin-bottom: 0.4rem; }

/* ---------- 5. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.8rem 1.8rem;
  font-family: var(--font-heading);
  font-size: 0.92rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  line-height: 1;
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: 2px;
  transition: background-color 0.25s ease, color 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease, transform 0.25s ease;
}
.btn-primary {
  background: var(--color-gold);
  border-color: var(--color-gold);
  color: var(--color-ink);
}
.btn-primary:hover {
  background: var(--color-yellow);
  border-color: var(--color-yellow);
  box-shadow: 0 0 20px rgba(201, 162, 39, 0.35);
}
.btn-ghost {
  background: transparent;
  border-color: var(--color-gold);
  color: var(--color-gold);
}
.btn-ghost:hover {
  background: rgba(201, 162, 39, 0.1);
  border-color: var(--color-yellow);
  color: var(--color-yellow);
}
.btn:active { transform: scale(0.98); }

/* ---------- 6. 标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.2rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  border: 1px solid;
  border-radius: 999px;
  white-space: nowrap;
}
.tag-gold {
  color: var(--color-gold);
  border-color: rgba(201, 162, 39, 0.45);
  background: rgba(201, 162, 39, 0.08);
}
.tag-ice {
  color: var(--color-ice);
  border-color: rgba(143, 184, 216, 0.4);
  background: rgba(143, 184, 216, 0.08);
}
.tag-red {
  color: #e25c68;
  border-color: rgba(166, 25, 46, 0.6);
  background: rgba(166, 25, 46, 0.15);
}
.tag-moss {
  color: var(--color-moss);
  border-color: rgba(94, 110, 94, 0.5);
  background: rgba(94, 110, 94, 0.15);
}

/* ---------- 7. 卡片 ---------- */
.card {
  background: linear-gradient(140deg, rgba(245, 240, 233, 0.05), rgba(245, 240, 233, 0.01));
  border: 1px solid rgba(245, 240, 233, 0.08);
  border-left: 3px solid var(--color-gold);
  padding: clamp(1.25rem, 3vw, 2rem);
  border-radius: 2px;
  transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
}
.card:hover {
  transform: translateY(-4px);
  border-color: rgba(201, 162, 39, 0.45);
  border-left-color: var(--color-gold);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.45);
}
.card-title {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}
.card p:last-child { margin-bottom: 0; }

/* ---------- 8. 网格 ---------- */
.grid {
  display: grid;
  gap: clamp(1.25rem, 3vw, 2.25rem);
}
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

/* ---------- 9. 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  color: var(--color-stone);
  padding-block: 1.25rem;
  list-style: none;
  margin: 0;
}
.breadcrumb a {
  color: var(--color-ice);
  text-decoration: none;
}
.breadcrumb a:hover {
  color: var(--color-gold);
}
.breadcrumb-item + .breadcrumb-item::before {
  content: '/';
  color: var(--color-stone);
  margin-right: 0.4rem;
}

/* ---------- 10. 图片容器 ---------- */
.frame {
  position: relative;
  display: block;
  overflow: hidden;
  background: linear-gradient(140deg, #1a1d24 0%, var(--color-ink) 100%);
  border: 1px solid rgba(201, 162, 39, 0.18);
}
.frame::before { content: ''; display: block; }
.frame-16x9::before { padding-top: 56.25%; }
.frame-4x3::before { padding-top: 75%; }
.frame-1x1::before { padding-top: 100%; }
.frame img,
.frame video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.frame-caption {
  font-size: 0.8rem;
  color: var(--color-stone);
  padding-top: 0.5rem;
}

/* ---------- 11. 章节目录 ---------- */
.toc {
  position: sticky;
  top: calc(var(--nav-offset) + 1rem);
  border-left: 1px solid rgba(201, 162, 39, 0.3);
  padding-left: 1.2rem;
}
.toc-title {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.24em;
  color: var(--color-stone);
  margin-bottom: 0.9rem;
}
.toc-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.toc-list li { margin-bottom: 0.25rem; }
.toc-link {
  display: block;
  position: relative;
  padding: 0.45rem 0.7rem;
  font-size: 0.88rem;
  color: var(--color-ice);
  text-decoration: none;
  border-left: 2px solid transparent;
  margin-left: -1.2rem;
  padding-left: 1.2rem;
  transition: color 0.25s ease, border-color 0.25s ease, background-color 0.25s ease;
}
.toc-link:hover,
.toc-link:focus-visible {
  color: var(--color-gold);
  background: rgba(201, 162, 39, 0.06);
}
.toc-link.is-active {
  color: var(--color-gold);
  border-left-color: var(--color-gold);
  background: rgba(201, 162, 39, 0.08);
  font-weight: 600;
}

/* ---------- 12. 背景分区工具 ---------- */
.bg-ice {
  background: linear-gradient(135deg, rgba(143, 184, 216, 0.08), rgba(143, 184, 216, 0.02));
}
.bg-moss {
  background: linear-gradient(135deg, rgba(94, 110, 94, 0.12), rgba(94, 110, 94, 0.03));
}

/* ---------- 13. 头部 ---------- */
.site-header {
  position: relative;
  background-color: var(--color-ink);
}
.skip-link {
  position: fixed;
  top: -100px;
  left: 1rem;
  z-index: 9999;
  background: var(--color-gold);
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-size: 0.9rem;
  font-weight: 800;
  padding: 0.75rem 1.5rem;
  border-radius: 0 0 4px 4px;
  text-decoration: none;
  transition: top 0.3s ease;
}
.skip-link:focus-visible { top: 0; }
[data-scroll-progress] {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0;
  background: linear-gradient(90deg, var(--color-gold), var(--color-yellow) 50%, var(--color-ice));
  box-shadow: 0 0 12px rgba(201, 162, 39, 0.6);
  z-index: 1000;
}
.masthead {
  position: relative;
  padding-top: clamp(2rem, 5vw, 4rem);
  padding-bottom: clamp(1.25rem, 3vw, 2rem);
  background:
    radial-gradient(ellipse 80% 120% at 50% -30%, rgba(143, 184, 216, 0.1) 0%, transparent 70%),
    linear-gradient(180deg, var(--color-ink) 0%, rgba(11, 12, 16, 0.97) 100%);
}
.masthead-row {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 1rem;
}
.masthead-meta {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.8rem;
  letter-spacing: 0.12em;
  color: var(--color-ice);
  opacity: 0.9;
}
.masthead-meta-left { justify-self: start; }
.masthead-meta-right { justify-self: end; }
.masthead-meta-icon {
  font-style: normal;
  font-size: 0.9rem;
}
.masthead-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.3rem 0.75rem;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--color-yellow);
  background: rgba(166, 25, 46, 0.14);
  border: 1px solid rgba(201, 162, 39, 0.4);
  border-radius: 2px;
}
.masthead-badge::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-red);
  box-shadow: 0 0 6px rgba(166, 25, 46, 0.9);
  animation: badgePulse 2.2s ease-in-out infinite;
}
@keyframes badgePulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.35; }
}
.brand {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  text-decoration: none;
  line-height: 1;
}
.brand-crystal {
  font-size: 1.5rem;
  line-height: 0.6;
  color: var(--color-gold);
  text-shadow: 0 0 16px rgba(201, 162, 39, 0.55);
}
.brand-word {
  font-family: var(--font-heading);
  font-size: clamp(2rem, 5vw, 2.8rem);
  font-weight: 800;
  color: var(--color-cream);
  letter-spacing: 0.06em;
  line-height: 1.2;
}
.brand-word em {
  font-style: normal;
  color: var(--color-gold);
}
.brand-slogan {
  display: block;
  font-size: 0.68rem;
  font-weight: 400;
  letter-spacing: 0.46em;
  text-indent: 0.23em;
  color: var(--color-ice);
  margin-top: 0.4rem;
}
.masthead-rule {
  position: relative;
  height: 1px;
  margin-top: clamp(1.25rem, 3vw, 2rem);
  background: linear-gradient(90deg, transparent 0%, rgba(201, 162, 39, 0.65) 15%, rgba(201, 162, 39, 0.25) 50%, rgba(201, 162, 39, 0.65) 85%, transparent 100%);
}
.rule-diamond {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 9px;
  height: 9px;
  background: var(--color-gold);
  transform: translate(-50%, -50%) rotate(45deg);
  box-shadow: 0 0 12px rgba(201, 162, 39, 0.8);
}
.masthead-rule::before,
.masthead-rule::after {
  content: '';
  position: absolute;
  top: 50%;
  width: 5px;
  height: 5px;
  background: var(--color-ice);
  transform: translateY(-50%) rotate(45deg);
  opacity: 0.75;
  box-shadow: 0 0 6px rgba(143, 184, 216, 0.4);
}
.masthead-rule::before { left: 18%; }
.masthead-rule::after { right: 18%; }

/* ---------- 14. 导航 ---------- */
.nav-shell {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(11, 12, 16, 0.92);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-top: 1px solid rgba(201, 162, 39, 0.15);
  border-bottom: 1px solid rgba(201, 162, 39, 0.2);
}
.nav-shell-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: var(--nav-offset);
  position: relative;
}
.nav-toggle { display: none; }
.nav-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: 0.4rem;
}
.nav-link {
  position: relative;
  display: inline-block;
  padding: 0.9rem 1.1rem;
  font-family: var(--font-heading);
  font-size: 0.92rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  color: var(--color-cream);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.25s ease;
}
.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0.55rem;
  left: 1.1rem;
  right: 1.1rem;
  height: 2px;
  background: linear-gradient(90deg, var(--color-gold), var(--color-yellow));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}
.nav-link:hover,
.nav-link:focus-visible,
.nav-link[aria-current="page"] {
  color: var(--color-gold);
}
.nav-link:hover::after,
.nav-link:focus-visible::after,
.nav-link[aria-current="page"]::after {
  transform: scaleX(1);
}

/* ---------- 15. 页脚 ---------- */
.site-footer {
  position: relative;
  background-color: var(--color-ink);
  background-image:
    linear-gradient(rgba(201, 162, 39, 0.028) 1px, transparent 1px),
    linear-gradient(90deg, rgba(143, 184, 216, 0.02) 1px, transparent 1px);
  background-size: 4rem 4rem;
  border-top: 1px solid rgba(201, 162, 39, 0.3);
}
.site-footer::before {
  content: '';
  position: absolute;
  top: -1px;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-gold), var(--color-ice) 50%, var(--color-gold));
  opacity: 0.8;
}
.footer-top {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(2rem, 5vw, 3.5rem);
  padding-block: clamp(2.5rem, 6vw, 4.5rem);
}
.footer-brand {
  flex: 2 1 300px;
  max-width: 480px;
}
.footer-col {
  flex: 1 1 150px;
  min-width: 120px;
}
.footer-col-contact {
  flex: 1.4 1 220px;
}
.brand-footer {
  align-items: flex-start;
  margin-bottom: 1.25rem;
}
.brand-footer .brand-crystal {
  font-size: 1.1rem;
}
.brand-footer .brand-word {
  font-size: 1.6rem;
}
.brand-footer .brand-slogan {
  font-size: 0.58rem;
  letter-spacing: 0.4em;
  margin-top: 0.3rem;
}
.footer-intro,
.footer-note {
  font-size: 0.88rem;
  line-height: 1.8;
  color: var(--color-stone);
}
.footer-intro {
  margin-bottom: 1rem;
}
.footer-note {
  border-left: 2px solid var(--color-gold);
  padding-left: 0.9rem;
  color: var(--color-ice);
  margin-bottom: 0;
}
.footer-title {
  font-family: var(--font-heading);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.22em;
  color: var(--color-gold);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid rgba(201, 162, 39, 0.22);
}
.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
}
.footer-links li {
  margin-bottom: 0.4rem;
}
.footer-links a {
  color: var(--color-cream);
  text-decoration: none;
  font-size: 0.9rem;
  opacity: 0.85;
  transition: color 0.2s ease, opacity 0.2s ease, padding-left 0.2s ease;
}
.footer-links a:hover {
  color: var(--color-gold);
  opacity: 1;
  padding-left: 0.35rem;
}
.footer-contact {
  list-style: none;
  margin: 0;
  padding: 0;
}
.footer-contact li {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
  margin-bottom: 0.9rem;
}
.footer-contact-label {
  font-size: 0.68rem;
  letter-spacing: 0.2em;
  color: var(--color-stone);
}
.footer-contact-value {
  font-size: 0.88rem;
  color: var(--color-cream);
  opacity: 0.9;
  line-height: 1.5;
  word-break: break-all;
  overflow-wrap: anywhere;
}
.footer-bottom {
  border-top: 1px solid rgba(201, 162, 39, 0.15);
  padding-block: 1.15rem;
}
.footer-bottom-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.6rem 1.5rem;
  font-size: 0.8rem;
  color: var(--color-stone);
}
.footer-copy {
  margin-bottom: 0;
}
.footer-meta {
  margin-bottom: 0;
  color: rgba(143, 184, 216, 0.75);
}

/* ---------- 16. 返回顶部 ---------- */
.back-top {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 900;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: rgba(11, 12, 16, 0.88);
  border: 1px solid var(--color-gold);
  color: var(--color-gold);
  font-size: 1.15rem;
  line-height: 1;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s ease, background-color 0.3s ease, color 0.3s ease, box-shadow 0.3s ease;
}
.back-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.back-top:hover,
.back-top:focus-visible {
  background: var(--color-gold);
  color: var(--color-ink);
  box-shadow: 0 0 24px rgba(201, 162, 39, 0.5);
}

/* ---------- 17. 响应式 ---------- */
@media (max-width: 1024px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .nav-link {
    padding: 0.85rem 0.7rem;
    font-size: 0.85rem;
    letter-spacing: 0.1em;
  }
}
@media (max-width: 768px) {
  [data-scroll-progress] { height: 2px; }
  .masthead-row {
    grid-template-columns: 1fr auto;
    gap: 0.75rem;
  }
  .masthead-meta-left { display: none; }
  .brand {
    justify-self: start;
  }
  .masthead-meta-right {
    justify-self: end;
  }
  .masthead-meta {
    font-size: 0.7rem;
  }
  .masthead-badge {
    padding: 0.25rem 0.6rem;
    font-size: 0.62rem;
  }
  .nav-shell-inner {
    justify-content: flex-end;
    min-height: 48px;
  }
  .nav-toggle {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.45rem 0.9rem;
    background: transparent;
    border: 1px solid rgba(201, 162, 39, 0.4);
    border-radius: 2px;
    color: var(--color-gold);
    font-size: 0.85rem;
    font-weight: 600;
    line-height: 1;
  }
  .nav-toggle-bars {
    display: inline-flex;
    flex-direction: column;
    gap: 3px;
    width: 14px;
  }
  .nav-toggle-bars span {
    display: block;
    height: 2px;
    background: currentColor;
    transition: transform 0.3s ease, opacity 0.3s ease;
  }
  .nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(1) {
    transform: translateY(5px) rotate(45deg);
  }
  .nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(2) {
    opacity: 0;
  }
  .nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(3) {
    transform: translateY(-5px) rotate(-45deg);
  }
  .site-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-ink);
    border-bottom: 1px solid rgba(201, 162, 39, 0.5);
    box-shadow: 0 16px 32px rgba(0, 0, 0, 0.6);
    animation: navDrop 0.3s ease forwards;
  }
  .site-nav[data-open] {
    display: block;
  }
  @keyframes navDrop {
    from { opacity: 0; transform: translateY(-6px); }
    to { opacity: 1; transform: translateY(0); }
  }
  .nav-list {
    flex-direction: column;
    align-items: stretch;
    padding: 0.5rem 1rem;
    gap: 0;
  }
  .nav-item {
    border-bottom: 1px solid rgba(245, 240, 233, 0.06);
  }
  .nav-item:last-child {
    border-bottom: none;
  }
  .nav-link {
    display: block;
    padding: 0.9rem 0.5rem;
    font-size: 1.02rem;
    letter-spacing: 0.08em;
  }
  .nav-link::after {
    display: none;
  }
  .nav-link[aria-current="page"] {
    color: var(--color-gold);
    background: rgba(201, 162, 39, 0.08);
    padding-left: 1rem;
  }
  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }
  .footer-top {
    gap: 2rem;
  }
  .footer-brand {
    flex-basis: 100%;
    max-width: none;
  }
  .footer-bottom-inner {
    flex-direction: column;
    align-items: flex-start;
  }
  .back-top {
    bottom: 1rem;
    right: 1rem;
    width: 42px;
    height: 42px;
  }
}

/* ---------- 18. 可访问性 ---------- */
:focus-visible {
  outline: 2px solid var(--color-gold);
  outline-offset: 2px;
}
@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;
  }
  .site-nav[data-open] {
    animation: none;
  }
  .masthead-badge::before {
    animation: none;
  }
}