/* ==========================================================================
   B官方品牌站 — Site Kit 共享样式 /assets/site.css
   主题：雪山数据流 · 高原经幡 · 体育数据门户
   ========================================================================== */

/* ---------- 1. 设计变量 ---------- */
:root {
  /* 色彩系统 */
  --color-primary: #145A8A;
  --color-primary-deep: #0E4064;
  --color-primary-soft: #1C76AD;
  --color-snow: #F4F6F7;
  --color-flag-blue: #2C8FBF;
  --color-flag-green: #2E9B6B;
  --color-flag-yellow: #E6A817;
  --color-flag-red: #C04848;
  --color-ink: #0B0E11;
  --color-gray: #9AA5B1;
  --color-silver: #DDE5E9;

  /* 字体 */
  --font-title: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Noto Serif SC", "Source Han Serif SC", "Songti SC", Georgia, serif;
  --font-mono: "JetBrains Mono", "Roboto Mono", "SFMono-Regular", Menlo, Consolas, monospace;

  /* 尺寸 */
  --container-width: 1200px;
  --header-top-h: 44px;
  --header-main-h: 76px;
  --header-total: 120px;

  /* 间距 */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 40px;
  --space-2xl: 64px;
  --space-3xl: 96px;

  /* 圆角与阴影 */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --shadow-sm: 0 2px 8px rgba(11, 14, 17, 0.08);
  --shadow-md: 0 4px 20px rgba(11, 14, 17, 0.12);
  --shadow-lg: 0 8px 32px rgba(11, 14, 17, 0.2);
  --glow-blue: 0 4px 24px rgba(20, 90, 138, 0.35);

  /* 过渡 */
  --ease: cubic-bezier(0.3, 0, 0.3, 1);
  --fast: 0.2s;
  --slow: 0.4s;
}

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

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

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-ink);
  background: var(--color-snow);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

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

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

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

ul, ol {
  list-style: none;
}

a {
  color: var(--color-flag-blue);
  text-decoration: none;
  transition: color var(--fast) var(--ease);
}

a:hover {
  color: var(--color-primary-soft);
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-title);
  font-weight: 700;
  line-height: 1.25;
  color: var(--color-ink);
}

p {
  margin-bottom: 1em;
}

/* ---------- 3. 布局容器 ---------- */
.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

@media (min-width: 1440px) {
  .container {
    padding: 0 var(--space-xl);
  }
}

/* ---------- 4. 可访问性 ---------- */
.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  top: -100px;
  left: var(--space-md);
  z-index: 9999;
  padding: 10px 20px;
  background: var(--color-primary);
  color: var(--color-snow);
  font-family: var(--font-title);
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: 0 0 var(--radius-md) var(--radius-md);
  box-shadow: var(--shadow-md);
  transition: top var(--fast) var(--ease);
}

.skip-link:focus {
  top: 0;
  outline: 3px solid var(--color-flag-yellow);
  outline-offset: 2px;
}

:focus-visible {
  outline: 3px solid var(--color-flag-yellow);
  outline-offset: 2px;
  border-radius: 2px;
}

/* ---------- 5. 头部 ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(11, 14, 17, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(244, 246, 247, 0.06);
  transition: background var(--slow) var(--ease), box-shadow var(--slow) var(--ease), border-color var(--slow) var(--ease);
}

body.has-hero .site-header {
  background: linear-gradient(180deg, rgba(11, 14, 17, 0.72) 0%, rgba(11, 14, 17, 0.42) 70%, rgba(11, 14, 17, 0.08) 100%);
  border-bottom-color: transparent;
}

.site-header.is-scrolled {
  background: rgba(11, 14, 17, 0.96);
  border-bottom-color: rgba(20, 90, 138, 0.45);
  box-shadow: 0 4px 28px rgba(11, 14, 17, 0.35);
}

.scroll-progress {
  position: absolute;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--color-flag-blue), var(--color-flag-green), var(--color-flag-yellow), var(--color-flag-red));
  border-radius: 0 3px 3px 0;
  z-index: 10;
  pointer-events: none;
}

.header-top {
  height: var(--header-top-h);
  display: flex;
  align-items: center;
  border-bottom: 1px solid rgba(244, 246, 247, 0.08);
}

.header-top-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-lg);
  width: 100%;
}

.header-tagline {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--color-gray);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.header-tagline-mark {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-flag-green);
  box-shadow: 0 0 0 3px rgba(46, 155, 107, 0.22);
  animation: pulse-dot 2.4s infinite;
}

@keyframes pulse-dot {
  0%, 100% { box-shadow: 0 0 0 3px rgba(46, 155, 107, 0.22); }
  50% { box-shadow: 0 0 0 7px rgba(46, 155, 107, 0); }
}

.header-search {
  position: relative;
  display: flex;
  align-items: center;
}

.search-input {
  width: 260px;
  height: 30px;
  padding: 0 34px 0 14px;
  background: rgba(244, 246, 247, 0.07);
  border: 1px solid rgba(244, 246, 247, 0.14);
  border-radius: 20px;
  font-family: var(--font-body);
  font-size: 0.8125rem;
  color: var(--color-snow);
  transition: border-color var(--fast) var(--ease), background var(--fast) var(--ease), box-shadow var(--fast) var(--ease);
}

.search-input::placeholder {
  color: rgba(244, 246, 247, 0.4);
}

.search-input:focus {
  outline: none;
  border-color: var(--color-flag-blue);
  background: rgba(244, 246, 247, 0.12);
  box-shadow: 0 0 0 3px rgba(44, 143, 191, 0.2);
}

.search-icon {
  position: absolute;
  right: 11px;
  width: 13px;
  height: 13px;
  border: 2px solid var(--color-gray);
  border-radius: 50%;
  pointer-events: none;
}

.search-icon::after {
  content: '';
  position: absolute;
  right: -4px;
  bottom: -2px;
  width: 6px;
  height: 2px;
  background: var(--color-gray);
  border-radius: 1px;
  transform: rotate(45deg);
}

.header-main {
  height: var(--header-main-h);
  display: flex;
  align-items: center;
}

.header-main-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-lg);
  width: 100%;
}

/* 品牌 */
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
  text-decoration: none;
}

.brand-mark {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-deep) 100%);
  color: var(--color-snow);
  font-family: var(--font-title);
  font-size: 1.375rem;
  font-weight: 800;
  box-shadow: 0 4px 16px rgba(20, 90, 138, 0.4);
  position: relative;
}

.brand-mark::after {
  content: '';
  position: absolute;
  bottom: 3px;
  left: 6px;
  right: 6px;
  height: 3px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--color-flag-blue), var(--color-flag-green), var(--color-flag-yellow));
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.25;
}

.brand-name {
  font-family: var(--font-title);
  font-size: 1.0625rem;
  font-weight: 800;
  color: var(--color-snow);
  letter-spacing: 0.02em;
}

.brand-version {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-style: normal;
  color: var(--color-gray);
  letter-spacing: 0.06em;
}

/* 导航 */
.site-nav {
  display: flex;
  align-items: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 2px;
}

.nav-link {
  display: block;
  padding: 8px 14px;
  font-family: var(--font-title);
  font-size: 0.875rem;
  font-weight: 600;
  color: rgba(244, 246, 247, 0.78);
  border-radius: 8px;
  text-decoration: none;
  position: relative;
  transition: color var(--fast) var(--ease), background var(--fast) var(--ease);
}

.nav-link:hover {
  color: var(--color-snow);
  background: rgba(20, 90, 138, 0.3);
}

.nav-link[aria-current="page"] {
  color: var(--color-snow);
  background: rgba(20, 90, 138, 0.4);
}

.nav-link[aria-current="page"]::after {
  content: '';
  position: absolute;
  left: 14px;
  right: 14px;
  bottom: 2px;
  height: 2px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--color-flag-blue), var(--color-flag-green), var(--color-flag-yellow));
}

/* 头部操作区 */
.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  flex-shrink: 0;
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 8px 20px;
  font-family: var(--font-title);
  font-size: 0.875rem;
  font-weight: 700;
  border-radius: 999px;
  text-decoration: none;
  transition: transform var(--fast) var(--ease), background var(--fast) var(--ease), box-shadow var(--fast) var(--ease), border-color var(--fast) var(--ease);
}

.btn-primary {
  background: var(--color-primary);
  color: var(--color-snow);
  border: 2px solid rgba(255, 255, 255, 0.08);
  box-shadow: var(--glow-blue);
}

.btn-primary:hover {
  background: var(--color-primary-soft);
  color: var(--color-snow);
  transform: translateY(-1px);
  box-shadow: 0 6px 32px rgba(20, 90, 138, 0.5);
}

.btn:focus-visible {
  outline: 3px solid var(--color-flag-yellow);
  outline-offset: 2px;
}

/* 汉堡按钮 */
.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 11px 9px;
  border-radius: 10px;
  background: rgba(244, 246, 247, 0.08);
  border: 1px solid rgba(244, 246, 247, 0.12);
  flex-direction: column;
  justify-content: center;
  gap: 5px;
}

.nav-toggle-bar {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--color-snow);
  border-radius: 2px;
  transition: transform var(--fast) var(--ease), opacity var(--fast) var(--ease);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* 头部经幡线 */
.header-ridge {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-flag-blue) 0%, var(--color-flag-green) 25%, var(--color-flag-yellow) 50%, var(--color-flag-red) 75%, var(--color-primary-soft) 100%);
  opacity: 0;
  transform: scaleX(0);
  transform-origin: left center;
  transition: opacity 0.35s var(--ease), transform 0.4s var(--ease);
}

.site-header.is-scrolled .header-ridge {
  opacity: 1;
  transform: scaleX(1);
}

/* ---------- 6. 页脚 ---------- */
.site-footer {
  background: var(--color-ink);
  color: var(--color-snow);
  position: relative;
}

.footer-ridge {
  height: 4px;
  background: linear-gradient(90deg, var(--color-flag-blue) 0%, var(--color-flag-green) 25%, var(--color-flag-yellow) 50%, var(--color-flag-red) 75%, var(--color-primary-soft) 100%);
}

.footer-mountain {
  height: 44px;
  background: var(--color-ink);
  clip-path: polygon(
    0% 100%, 0% 35%, 3% 48%, 7% 22%, 12% 50%, 17% 16%,
    23% 45%, 29% 24%, 35% 58%, 40% 14%, 46% 36%, 52% 22%,
    58% 62%, 64% 18%, 70% 40%, 76% 12%, 82% 34%, 89% 20%,
    95% 46%, 100% 26%, 100% 100%
  );
  margin-top: -1px;
}

.footer-inner {
  display: grid;
  grid-template-columns: 1.4fr 0.8fr 0.8fr 1.2fr;
  gap: var(--space-xl);
  padding-top: var(--space-xl);
  padding-bottom: var(--space-2xl);
}

.footer-col-brand .brand {
  margin-bottom: var(--space-md);
}

.footer-trust {
  font-size: 0.875rem;
  line-height: 1.7;
  color: rgba(244, 246, 247, 0.65);
  margin-bottom: var(--space-lg);
  max-width: 340px;
}

.footer-contact-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.contact-chip {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(20, 90, 138, 0.2);
  border: 1px solid rgba(44, 143, 191, 0.35);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-flag-blue);
}

.footer-title {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--color-snow);
  letter-spacing: 0.06em;
  margin-bottom: var(--space-md);
  position: relative;
  padding-bottom: 8px;
}

.footer-title::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 28px;
  height: 2px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--color-flag-blue), var(--color-flag-green));
}

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

.footer-links a {
  color: rgba(244, 246, 247, 0.65);
  font-size: 0.875rem;
  transition: color var(--fast) var(--ease), padding-left var(--fast) var(--ease);
}

.footer-links a:hover {
  color: var(--color-flag-blue);
  padding-left: 4px;
}

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

.footer-contact-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  background: rgba(244, 246, 247, 0.03);
  border: 1px solid rgba(244, 246, 247, 0.06);
}

.footer-contact-label {
  font-family: var(--font-title);
  font-size: 0.6875rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-gray);
}

.footer-contact-value {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: rgba(244, 246, 247, 0.85);
}

.footer-bottom {
  border-top: 1px solid rgba(244, 246, 247, 0.08);
  background: rgba(0, 0, 0, 0.25);
  padding: var(--space-md) 0;
}

.footer-bottom-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.footer-copyright,
.footer-icp {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: rgba(244, 246, 247, 0.5);
}

/* 返回顶部 */
.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 900;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-primary);
  color: var(--color-snow);
  border: 2px solid rgba(255, 255, 255, 0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.125rem;
  box-shadow: 0 4px 20px rgba(11, 14, 17, 0.4);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px) scale(0.9);
  transition: opacity var(--slow) var(--ease), transform var(--slow) var(--ease), background var(--fast) var(--ease), visibility 0s var(--slow);
}

.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) scale(1);
  transition: opacity var(--slow) var(--ease), transform var(--slow) var(--ease), background var(--fast) var(--ease), visibility 0s 0s;
}

.back-to-top:hover {
  background: var(--color-primary-soft);
  box-shadow: 0 6px 28px rgba(20, 90, 138, 0.6);
  transform: translateY(-2px);
}

.back-to-top:focus-visible {
  outline: 3px solid var(--color-flag-yellow);
  outline-offset: 2px;
}

/* ---------- 7. 通用页面组件 ---------- */

/* 主体 */
.main-content {
  min-height: 60vh;
  padding-top: var(--header-total);
}

body.has-hero .main-content {
  padding-top: 0;
}

.content-width {
  max-width: 720px;
  margin: 0 auto;
}

/* 面包屑 */
.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
  font-family: var(--font-title);
  font-size: 0.8125rem;
  color: var(--color-gray);
  margin-bottom: var(--space-lg);
  padding-top: 12px;
}

.breadcrumb a {
  color: var(--color-flag-blue);
}

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

.breadcrumb-separator {
  color: var(--color-gray);
  font-size: 0.75rem;
}

.breadcrumb-current {
  color: var(--color-ink);
}

/* 堆叠面板 */
.stack-panel {
  padding: var(--space-3xl) 0;
  position: relative;
}

.stack-panel + .stack-panel {
  margin-top: -1px;
}

.panel-dark {
  background: var(--color-primary);
  color: var(--color-snow);
}

.panel-dark h1,
.panel-dark h2,
.panel-dark h3 {
  color: var(--color-snow);
}

.panel-snow {
  background: var(--color-snow);
}

.panel-glass {
  background: var(--color-silver);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

/* 网格 */
.grid {
  display: grid;
  gap: var(--space-lg);
}

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

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

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

@media (max-width: 992px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
}

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

/* 图片容器 */
.image-ratio-16-9,
.image-ratio-4-3,
.image-ratio-1-1 {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-md);
}

.image-ratio-16-9 { aspect-ratio: 16 / 9; }
.image-ratio-4-3 { aspect-ratio: 4 / 3; }
.image-ratio-1-1 { aspect-ratio: 1 / 1; }

.image-ratio-16-9 img,
.image-ratio-4-3 img,
.image-ratio-1-1 img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.image-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gray);
  background: linear-gradient(135deg, var(--color-silver) 0%, var(--color-snow) 100%);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
}

/* 标签 */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px;
  border-radius: 999px;
  font-family: var(--font-title);
  font-size: 0.6875rem;
  font-weight: 700;
  letter-spacing: 0.06em;
}

.tag-version {
  background: rgba(46, 155, 107, 0.15);
  color: var(--color-flag-green);
  border: 1px solid rgba(46, 155, 107, 0.3);
}

.tag-new {
  background: rgba(230, 168, 23, 0.15);
  color: var(--color-flag-yellow);
  border: 1px solid rgba(230, 168, 23, 0.3);
}

.tag-warning {
  background: rgba(192, 72, 72, 0.15);
  color: var(--color-flag-red);
  border: 1px solid rgba(192, 72, 72, 0.35);
}

/* 数据等宽 */
.mono-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
}

/* 章节标题 */
.section-title {
  font-size: 2rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: var(--space-sm);
  position: relative;
}

.section-title::before {
  content: '';
  display: inline-block;
  width: 6px;
  height: 28px;
  background: linear-gradient(180deg, var(--color-flag-blue), var(--color-flag-green));
  border-radius: 3px;
  margin-right: 12px;
  vertical-align: -4px;
}

.section-subtitle {
  font-size: 1rem;
  color: var(--color-gray);
  margin-bottom: var(--space-lg);
}

/* 折叠卡片 */
.collapse-card {
  background: var(--color-snow);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(11, 14, 17, 0.04);
  overflow: hidden;
}

.collapse-card-header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  width: 100%;
  padding: var(--space-md) var(--space-lg);
  font-family: var(--font-title);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--color-ink);
  text-align: left;
  background: transparent;
  border: none;
  cursor: pointer;
  transition: background var(--fast) var(--ease), color var(--fast) var(--ease);
}

.collapse-card-header:hover {
  background: rgba(20, 90, 138, 0.06);
  color: var(--color-primary);
}

.collapse-card-header::after {
  content: '';
  display: inline-block;
  width: 8px;
  height: 8px;
  border-right: 2px solid var(--color-gray);
  border-bottom: 2px solid var(--color-gray);
  transform: rotate(45deg);
  transition: transform var(--fast) var(--ease), border-color var(--fast) var(--ease);
  margin-left: auto;
  flex-shrink: 0;
}

.collapse-card[data-expanded] .collapse-card-header::after {
  transform: rotate(-135deg);
  border-color: var(--color-primary);
}

.collapse-card-body {
  display: none;
  padding: 0 var(--space-lg);
}

.collapse-card[data-expanded] .collapse-card-body {
  display: block;
  padding: 0 var(--space-lg) var(--space-lg);
}

/* 经幡色装饰分隔线 */
.divider-flag {
  height: 3px;
  border: none;
  border-radius: 3px;
  background: linear-gradient(90deg, var(--color-flag-blue), var(--color-flag-green), var(--color-flag-yellow), var(--color-flag-red));
  margin: var(--space-lg) 0;
  opacity: 0.7;
}

/* ---------- 8. 响应式 ---------- */
@media (max-width: 1024px) {
  :root {
    --header-top-h: 40px;
    --header-main-h: 68px;
    --header-total: 108px;
  }

  .search-input {
    width: 200px;
  }

  .nav-link {
    padding: 8px 10px;
    font-size: 0.8125rem;
  }
}

@media (max-width: 860px) {
  :root {
    --header-top-h: 0px;
    --header-main-h: 64px;
    --header-total: 64px;
  }

  .header-top {
    display: none;
  }

  .site-header {
    background: rgba(11, 14, 17, 0.95);
  }

  body.has-hero .site-header {
    background: rgba(11, 14, 17, 0.68);
  }

  .site-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    background: rgba(11, 14, 17, 0.98);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    padding: var(--space-sm) 0 var(--space-md);
    border-bottom: 1px solid var(--color-primary);
    box-shadow: 0 16px 32px rgba(0, 0, 0, 0.35);
    max-height: calc(100vh - var(--header-main-h));
    overflow-y: auto;
  }

  .site-nav[data-open] {
    display: flex;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    width: 100%;
  }

  .nav-link {
    padding: 14px 20px;
    font-size: 1rem;
    border-radius: 0;
    border-left: 3px solid transparent;
  }

  .nav-link:hover,
  .nav-link[aria-current="page"] {
    background: rgba(20, 90, 138, 0.25);
    border-left-color: var(--color-flag-blue);
  }

  .nav-link[aria-current="page"]::after {
    display: none;
  }

  .nav-toggle {
    display: flex;
  }

  .header-actions {
    gap: 10px;
  }

  .btn-cta {
    padding: 6px 14px;
    font-size: 0.8125rem;
  }

  .footer-inner {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-lg);
  }
}

@media (max-width: 640px) {
  .footer-inner {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }

  .footer-col-brand {
    text-align: left;
  }
}

@media (max-width: 480px) {
  .brand-version {
    display: none;
  }

  .brand-name {
    font-size: 0.9375rem;
  }

  .brand-mark {
    width: 38px;
    height: 38px;
    font-size: 1.125rem;
  }

  .btn-cta {
    padding: 5px 12px;
    font-size: 0.75rem;
  }

  .back-to-top {
    right: 16px;
    bottom: 16px;
    width: 38px;
    height: 38px;
    font-size: 1rem;
  }

  .footer-bottom-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-xs);
  }
}

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

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

  .header-tagline-mark {
    animation: none;
  }
}