/* ============================================================
   星空体育入口 / 共享样式体系 / site.css
   ============================================================ */

/* ---------- 1. CSS 变量 ---------- */
:root {
  --color-bg: #0B1B3F;
  --color-bg-deep: #070F2A;
  --color-surface: #16295A;
  --color-glass: rgba(11, 27, 63, 0.8);
  --color-accent: #39FF14;
  --color-warning: #FF6A00;
  --color-text: #FFFFFF;
  --color-muted: #A0B0C0;
  --color-border: #4A6FA5;
  --color-border-dim: rgba(74, 111, 165, 0.35);

  --font-body: "Noto Sans CJK SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-mono: "Roboto Mono", "SF Mono", "Cascadia Code", Consolas, monospace;

  --header-width: 268px;
  --content-max: 1240px;
  --gutter: clamp(1.25rem, 3.5vw, 2.5rem);
  --radius: 6px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --shadow-card: 0 10px 40px rgba(0, 0, 0, 0.35);
  --shadow-hover: 0 18px 56px rgba(0, 0, 0, 0.5);
}

/* ---------- 2. Reset 与基础 ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  background-image:
    radial-gradient(ellipse at 85% 15%, rgba(57, 255, 20, 0.06) 0%, transparent 50%),
    radial-gradient(ellipse at 40% 90%, rgba(74, 111, 165, 0.14) 0%, transparent 55%);
  -webkit-font-smoothing: antialiased;
  margin-left: var(--header-width);
}

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

a {
  color: inherit;
}

button {
  font-family: inherit;
}

::selection {
  background: var(--color-accent);
  color: var(--color-bg-deep);
}

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

#main-content {
  display: block;
  outline: none;
}

/* ---------- 3. 跳过链接 ---------- */
.skip-link {
  position: fixed;
  top: -120%;
  left: 50%;
  transform: translateX(-50%);
  z-index: 999;
  padding: 0.65rem 1.75rem;
  background: var(--color-accent);
  color: var(--color-bg-deep);
  font-weight: 700;
  font-size: 0.9rem;
  text-decoration: none;
  border-radius: 0 0 var(--radius) var(--radius);
  box-shadow: 0 4px 24px rgba(57, 255, 20, 0.4);
  transition: top 0.3s var(--ease);
}

.skip-link:focus-visible {
  top: 0;
}

/* ---------- 4. 滚动进度条 ---------- */
.scroll-progress {
  --progress: 0%;
  position: fixed;
  top: 0;
  left: var(--header-width);
  right: 0;
  height: 3px;
  z-index: 300;
  pointer-events: none;
  background: rgba(74, 111, 165, 0.15);
}

.scroll-progress::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: var(--progress, 0%);
  background: linear-gradient(90deg, var(--color-accent), var(--color-warning));
  box-shadow: 0 0 12px rgba(57, 255, 20, 0.55);
  transition: width 0.15s linear;
}

/* ---------- 5. 头部 · 侧边品牌轨道 ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--header-width);
  height: 100vh;
  z-index: 200;
  background: linear-gradient(180deg, #0D1F45 0%, var(--color-bg-deep) 100%);
  border-right: 1px solid var(--color-border-dim);
  overflow: hidden;
}

.site-header::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: repeating-linear-gradient(
    -45deg,
    transparent 0 14px,
    rgba(57, 255, 20, 0.025) 14px 28px
  );
}

.brand-rail {
  position: relative;
  display: flex;
  flex-direction: column;
  height: 100%;
  overflow-y: auto;
}

/* 品牌标识 */
.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1.75rem 1.5rem 1.5rem;
  text-decoration: none;
  border-bottom: 1px solid var(--color-border-dim);
}

.brand-mark {
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: linear-gradient(135deg, var(--color-accent), #12C98F);
  color: var(--color-bg-deep);
  font-family: var(--font-mono);
  font-size: 1.4rem;
  font-weight: 900;
  line-height: 1;
  clip-path: polygon(0 0, 100% 0, 100% 70%, 50% 100%, 0 70%);
  box-shadow: 0 0 18px rgba(57, 255, 20, 0.25);
}

.brand-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
  line-height: 1.15;
}

.brand-name {
  font-size: 1.18rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  color: var(--color-text);
}

.brand-sub {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  letter-spacing: 0.22em;
  color: var(--color-accent);
  text-transform: uppercase;
  white-space: nowrap;
}

/* 导航 */
.site-nav {
  flex: 0 0 auto;
  padding: 1rem 0;
}

.nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  padding: 0.65rem 1.5rem;
  color: var(--color-muted);
  text-decoration: none;
  font-size: 0.95rem;
  letter-spacing: 0.02em;
  border-left: 2px solid transparent;
  background-size: 0% 100%;
  background-repeat: no-repeat;
  background-position: left center;
  background-image: linear-gradient(90deg, rgba(57, 255, 20, 0.12), rgba(57, 255, 20, 0.02));
  transition:
    color 0.3s var(--ease),
    border-color 0.3s var(--ease),
    background-size 0.4s var(--ease);
}

.nav-link:hover {
  color: var(--color-text);
  border-left-color: var(--color-accent);
  background-size: 100% 100%;
}

.nav-link[aria-current="page"] {
  color: var(--color-text);
  border-left-color: var(--color-accent);
  background-size: 100% 100%;
  font-weight: 600;
}

.nav-link[aria-current="page"] .nav-index {
  color: var(--color-accent);
}

.nav-index {
  flex: 0 0 auto;
  min-width: 1.8rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  color: var(--color-border);
  transition: color 0.3s var(--ease);
}

.nav-label {
  white-space: nowrap;
}

/* 轨道底部 */
.rail-foot {
  margin-top: auto;
  padding: 1.1rem 1.5rem 1.4rem;
  border-top: 1px solid var(--color-border-dim);
  position: relative;
}

.rail-foot::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: repeating-linear-gradient(
    -45deg,
    var(--color-accent) 0 8px,
    transparent 8px 16px
  );
  opacity: 0.7;
}

.rail-live {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-top: 0.5rem;
}

.rail-live-dot {
  flex: 0 0 auto;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-accent);
  box-shadow: 0 0 10px rgba(57, 255, 20, 0.9);
  animation: pulse-dot 1.8s ease-in-out infinite;
}

.rail-live-text {
  font-size: 0.8rem;
  color: var(--color-muted);
}

.rail-mono {
  margin-top: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.16em;
  color: var(--color-border);
  text-transform: uppercase;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.8); }
}

/* 汉堡按钮（默认隐藏） */
.nav-toggle {
  display: none;
}

/* ---------- 6. 页脚 ---------- */
.site-footer {
  position: relative;
  background:
    linear-gradient(180deg, rgba(11, 27, 63, 0.35), var(--color-bg-deep) 45%),
    repeating-linear-gradient(-45deg, transparent 0 20px, rgba(57, 255, 20, 0.015) 20px 40px);
  border-top: 1px solid var(--color-border-dim);
  padding: clamp(2.5rem, 5vw, 4.5rem) 0 0;
  margin-top: clamp(2.5rem, 5vw, 5rem);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.6fr;
  gap: 2.25rem;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  align-items: flex-start;
}

.footer-logo {
  display: inline-flex;
  align-items: baseline;
  gap: 0.3rem;
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: 0.03em;
  color: var(--color-text);
  text-decoration: none;
}

.footer-logo-accent {
  color: var(--color-accent);
}

.footer-desc {
  max-width: 34ch;
  font-size: 0.9rem;
  color: var(--color-muted);
  line-height: 1.75;
}

.footer-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 0.4rem;
  padding: 0.35rem 0.95rem;
  border: 1px solid rgba(57, 255, 20, 0.35);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--color-accent);
  background: rgba(57, 255, 20, 0.05);
}

.footer-badge-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--color-accent);
  box-shadow: 0 0 8px rgba(57, 255, 20, 0.8);
  animation: pulse-dot 1.8s ease-in-out infinite;
}

.footer-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--color-border-dim);
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-accent);
}

.footer-title::before {
  content: "//";
  color: var(--color-border);
}

.footer-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.footer-list a {
  color: var(--color-muted);
  text-decoration: none;
  font-size: 0.92rem;
  transition: color 0.3s var(--ease), padding-left 0.3s var(--ease);
}

.footer-list a:hover {
  color: var(--color-accent);
  padding-left: 4px;
}

.footer-contact-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.footer-contact-list li {
  display: flex;
  gap: 0.75rem;
  align-items: baseline;
  font-size: 0.88rem;
  color: var(--color-muted);
  line-height: 1.55;
}

.footer-contact-label {
  flex: 0 0 auto;
  min-width: 2.5em;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--color-accent);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6rem 1.5rem;
  margin-top: clamp(2rem, 4vw, 3.5rem);
  padding: 1.1rem 0 1.6rem;
  border-top: 1px solid var(--color-border-dim);
  font-family: var(--font-mono);
  font-size: 0.78rem;
}

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

.footer-icp {
  color: var(--color-border);
}

.footer-note {
  width: 100%;
  flex-basis: 100%;
  font-family: var(--font-body);
  font-size: 0.85rem;
  color: var(--color-muted);
}

/* ---------- 7. 布局工具 ---------- */
.container {
  width: 100%;
  max-width: calc(var(--content-max) + 2 * var(--gutter));
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.main-wrap {
  padding-block: clamp(1.5rem, 3.5vw, 3rem);
}

.section {
  padding-block: clamp(2.25rem, 5vw, 4.5rem);
}

.section-head {
  max-width: 72ch;
  margin-bottom: clamp(1.5rem, 3vw, 2.5rem);
}

.section-kicker {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-accent);
}

.section-kicker::before {
  content: "";
  width: 2.2em;
  height: 1px;
  background: var(--color-accent);
}

.section-title {
  font-size: clamp(1.5rem, 3.5vw, 2.4rem);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: 0.01em;
  color: var(--color-text);
}

.section-sub {
  margin-top: 0.6rem;
  font-size: 0.95rem;
  color: var(--color-muted);
  line-height: 1.7;
}

.page-hero {
  position: relative;
  padding: clamp(2.5rem, 6vw, 5rem) 0 clamp(2rem, 5vw, 3.5rem);
  border-bottom: 1px solid var(--color-border-dim);
  margin-bottom: clamp(1.5rem, 4vw, 3rem);
  overflow: hidden;
}

.page-hero::before {
  content: "";
  position: absolute;
  right: -8%;
  top: -15%;
  bottom: -15%;
  width: 32%;
  background: repeating-linear-gradient(
    -45deg,
    transparent 0 12px,
    rgba(57, 255, 20, 0.05) 12px 24px
  );
  clip-path: polygon(20% 0, 100% 0, 80% 100%, 0 100%);
  pointer-events: none;
}

.page-hero-title {
  position: relative;
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 800;
  line-height: 1.12;
  letter-spacing: 0.01em;
  color: var(--color-text);
}

.page-hero-desc {
  position: relative;
  margin-top: 1rem;
  max-width: 62ch;
  font-size: 1.02rem;
  color: var(--color-muted);
  line-height: 1.75;
}

.divider {
  height: 1px;
  border: 0;
  margin: 2.5rem 0;
  background: var(--color-border-dim);
}

/* ---------- 8. 网格 ---------- */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.5rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.5rem;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1.5rem;
}

.grid-gap-sm { gap: 1rem; }
.grid-gap-lg { gap: 2.5rem; }

/* ---------- 9. 卡片 ---------- */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border-dim);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition:
    transform 0.4s var(--ease),
    box-shadow 0.4s var(--ease),
    border-color 0.4s var(--ease);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card);
  border-color: rgba(57, 255, 20, 0.35);
}

.data-card {
  background: linear-gradient(135deg, var(--color-surface), rgba(11, 27, 63, 0.65));
  border: 1px solid var(--color-border-dim);
  border-left: 3px solid var(--color-accent);
  border-radius: var(--radius);
  padding: 1.5rem;
  font-family: var(--font-mono);
  transition:
    transform 0.4s var(--ease),
    box-shadow 0.4s var(--ease);
}

.data-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.glass-panel {
  background: var(--color-glass);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius);
  padding: 1.5rem;
}

/* ---------- 10. 标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.25rem 0.75rem;
  border: 1px solid var(--color-border-dim);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--color-muted);
  background: rgba(74, 111, 165, 0.08);
}

.tag-green {
  border-color: rgba(57, 255, 20, 0.4);
  color: var(--color-accent);
  background: rgba(57, 255, 20, 0.06);
}

.tag-orange {
  border-color: rgba(255, 106, 0, 0.4);
  color: var(--color-warning);
  background: rgba(255, 106, 0, 0.06);
}

/* ---------- 11. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: var(--radius);
  cursor: pointer;
  transition:
    background-color 0.3s var(--ease),
    color 0.3s var(--ease),
    border-color 0.3s var(--ease),
    box-shadow 0.3s var(--ease);
}

.btn-primary {
  background: var(--color-accent);
  color: var(--color-bg-deep);
}

.btn-primary:hover {
  background: #6CFF4B;
  box-shadow: 0 0 28px rgba(57, 255, 20, 0.4);
}

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

.btn-ghost:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: rgba(57, 255, 20, 0.05);
  box-shadow: 0 0 18px rgba(57, 255, 20, 0.12);
}

/* ---------- 12. 表格 ---------- */
.data-table-wrap {
  width: 100%;
  overflow-x: auto;
  background: var(--color-surface);
  border: 1px solid var(--color-border-dim);
  border-radius: var(--radius);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.data-table th,
.data-table td {
  padding: 0.75rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--color-border-dim);
  white-space: nowrap;
}

.data-table th {
  font-family: var(--font-mono);
  font-size: 0.76rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-accent);
  background: rgba(57, 255, 20, 0.04);
}

.data-table td {
  color: var(--color-text);
}

.data-table tbody tr {
  transition: background-color 0.3s var(--ease);
}

.data-table tbody tr:hover {
  background: rgba(74, 111, 165, 0.14);
}

.data-table tbody tr:last-child td {
  border-bottom: none;
}

/* ---------- 13. 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.4rem;
  padding-block: 1rem;
  margin-bottom: 0.5rem;
  list-style: none;
  font-size: 0.85rem;
  font-family: var(--font-mono);
  color: var(--color-muted);
}

.breadcrumb li {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

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

.breadcrumb a {
  color: var(--color-muted);
  text-decoration: none;
  transition: color 0.3s var(--ease);
}

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

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

/* ---------- 14. 图片占位 ---------- */
.media-box {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  border: 1px dashed var(--color-border);
  border-radius: var(--radius);
  background: linear-gradient(145deg, var(--color-surface), var(--color-bg-deep));
}

.media-box::before {
  content: attr(data-label);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  color: var(--color-muted);
}

.media-box::after {
  content: "";
  position: absolute;
  top: -60%;
  left: -60%;
  width: 220%;
  height: 220%;
  background: linear-gradient(
    45deg,
    transparent 47%,
    rgba(74, 111, 165, 0.09) 49%,
    rgba(57, 255, 20, 0.06) 51%,
    transparent 53%
  );
  animation: sweep 7s linear infinite;
}

@keyframes sweep {
  0% { transform: translateX(-25%); }
  100% { transform: translateX(25%); }
}

/* ---------- 15. 正文排版 ---------- */
.prose {
  max-width: 72ch;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--color-muted);
}

.prose h2 {
  margin: 2.5rem 0 1rem;
  font-size: clamp(1.4rem, 2.5vw, 1.9rem);
  font-weight: 800;
  line-height: 1.3;
  color: var(--color-text);
}

.prose h3 {
  margin: 2rem 0 0.75rem;
  font-size: clamp(1.15rem, 2vw, 1.4rem);
  font-weight: 700;
  color: var(--color-text);
}

.prose p {
  margin-bottom: 1.25rem;
}

.prose a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.prose a:hover {
  color: var(--color-text);
}

.prose ul {
  margin-bottom: 1.25rem;
  padding-left: 1.4rem;
  list-style: none;
}

.prose ul li {
  position: relative;
  margin-bottom: 0.5rem;
}

.prose ul li::before {
  content: "▸";
  position: absolute;
  left: -1.3rem;
  color: var(--color-accent);
  font-family: var(--font-mono);
}

/* ---------- 16. 显露动画 ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition:
    opacity 0.7s var(--ease),
    transform 0.7s var(--ease);
}

[data-reveal].is-revealed {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- 17. 响应式 ---------- */
@media (max-width: 1200px) {
  .footer-grid {
    grid-template-columns: 1.6fr 1fr 1fr;
  }
  .footer-contact {
    grid-column: 1 / -1;
  }
}

@media (max-width: 992px) {
  body {
    margin-left: 0;
  }

  .site-header {
    position: sticky;
    top: 0;
    width: 100%;
    height: 64px;
    border-right: 0;
    border-bottom: 1px solid var(--color-border-dim);
    overflow: visible;
  }

  .brand-rail {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    height: 64px;
    padding: 0 1rem;
    overflow: visible;
  }

  .brand {
    padding: 0;
    border-bottom: 0;
  }

  .brand-mark {
    width: 38px;
    height: 38px;
    font-size: 1.15rem;
    box-shadow: 0 0 12px rgba(57, 255, 20, 0.2);
  }

  .brand-sub {
    font-size: 0.56rem;
    letter-spacing: 0.16em;
  }

  .nav-toggle {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 5px;
    width: 44px;
    height: 44px;
    flex: 0 0 auto;
    background: transparent;
    border: 1px solid var(--color-border-dim);
    border-radius: var(--radius);
    cursor: pointer;
    transition: border-color 0.3s var(--ease);
  }

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

  .nav-toggle-bar {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--color-text);
    border-radius: 1px;
    transition:
      transform 0.35s var(--ease),
      opacity 0.3s var(--ease),
      background-color 0.3s var(--ease);
  }

  .nav-toggle[data-open] .nav-toggle-bar:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
    background: var(--color-accent);
  }

  .nav-toggle[data-open] .nav-toggle-bar:nth-child(2) {
    opacity: 0;
  }

  .nav-toggle[data-open] .nav-toggle-bar:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
    background: var(--color-accent);
  }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    z-index: 150;
    max-height: 0;
    overflow: hidden;
    background: rgba(7, 15, 42, 0.97);
    border-bottom: 1px solid transparent;
    transition:
      max-height 0.45s var(--ease),
      border-color 0.3s var(--ease);
    padding: 0;
  }

  .site-nav[data-open] {
    max-height: calc(100vh - 64px);
    overflow-y: auto;
    border-bottom-color: var(--color-border-dim);
  }

  .nav-list {
    padding: 0.75rem 0 1rem;
    gap: 0.1rem;
  }

  .nav-link {
    padding: 0.7rem 1.5rem;
    font-size: 1rem;
  }

  .rail-foot {
    display: none;
  }

  .scroll-progress {
    left: 0;
  }

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

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2.25rem 1.5rem;
  }

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

  .footer-contact {
    grid-column: 1 / -1;
    border-top: 1px solid var(--color-border-dim);
    padding-top: 1.5rem;
  }
}

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

  .grid-gap-lg,
  .grid-gap-sm {
    gap: 1.25rem;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 1.75rem;
  }

  .footer-brand {
    grid-column: auto;
  }

  .footer-contact {
    grid-column: auto;
  }

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

  .footer-note {
    width: auto;
  }

  .btn {
    width: 100%;
  }
}

/* ---------- 18. 无障碍与动效偏好 ---------- */
@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;
  }

  [data-reveal] {
    opacity: 1;
    transform: none;
  }

  .scroll-progress::before {
    transition: none;
  }
}

@media (min-width: 993px) {
  .site-nav {
    display: block;
  }
}