/* ==========================================================
   云开体育官网CN — 共享样式 /assets/site.css
   设计体系：深空编辑控制台 / 轨道导航 / 档案卡系统
   ========================================================== */

/* ---------- 1. Reset ---------- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* ---------- 2. CSS 变量 ---------- */
:root {
  /* 色彩 */
  --c-primary: #0B1B3D;
  --c-primary-light: #1B3A6B;
  --c-accent: #FF7A00;
  --c-accent-soft: #FFB380;
  --c-silver: #C0C0C0;
  --c-gold: #FFD700;
  --c-paper: #F5EFE6;
  --c-ink: #1A1A1A;
  --c-red: #E4572E;
  --c-green: #2FA36B;
  --c-white: #FFFFFF;

  /* 字体 */
  --font-display: Futura, 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-body: Georgia, 'Noto Serif SC', 'Songti SC', 'SimSun', serif;
  --font-data: 'Roboto Mono', 'SF Mono', 'Cascadia Mono', Consolas, monospace;

  /* 布局 */
  --sidebar-w: 240px;
  --topbar-h: 64px;
  --container-w: 1200px;

  /* 间距 */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 16px;
  --space-4: 24px;
  --space-5: 40px;
  --space-6: 64px;
  --space-7: 96px;
  --space-8: 128px;

  /* 阴影 */
  --shadow-sm: 4px 4px 0 rgba(11, 27, 61, 0.14);
  --shadow-md: 8px 8px 0 rgba(11, 27, 61, 0.12);
  --shadow-lg: 12px 12px 0 rgba(11, 27, 61, 0.10);

  /* 边框 */
  --border-w: 2px;
  --border-w-thick: 4px;

  /* 过渡 */
  --transition-fast: 0.2s ease;
  --transition-base: 0.4s ease;

  /* 层级 */
  --z-header: 1000;
  --z-nav: 900;
  --z-skip: 2000;
}

/* ---------- 3. 基础排版 ---------- */
html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--c-ink);
  background: var(--c-paper);
  padding-left: var(--sidebar-w);
  min-height: 100vh;
}

p {
  margin-bottom: 1em;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  color: var(--c-primary);
  line-height: 1.2;
  margin-bottom: 0.6em;
}

a {
  color: var(--c-accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

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

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

ul, ol {
  padding-left: 1.4em;
}

/* 等宽数据类 */
code, kbd, samp {
  font-family: var(--font-data);
  font-size: 0.9em;
}

/* ---------- 4. 正文容器与主区域 ---------- */
#main-content {
  display: block;
  scroll-margin-top: 16px;
  outline: none;
  min-height: calc(100vh - 240px);
}

.container {
  max-width: calc(var(--container-w) + 48px);
  margin: 0 auto;
  padding: var(--space-5) var(--space-4);
}

.container-wide {
  max-width: 1440px;
}

.container-narrow {
  max-width: 720px;
}

/* ---------- 5. 无障碍跳转链接 ---------- */
.skip-link {
  position: fixed;
  top: -120px;
  left: 16px;
  z-index: var(--z-skip);
  display: inline-block;
  padding: 12px 24px;
  background: var(--c-accent);
  color: var(--c-primary);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 14px;
  line-height: 1;
  text-decoration: none;
  box-shadow: var(--shadow-sm);
  transition: top var(--transition-fast);
}

.skip-link:focus-visible {
  top: 16px;
}

/* ---------- 6. 头部 — 桌面端侧栏 ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: var(--sidebar-w);
  height: 100vh;
  background: var(--c-primary);
  z-index: var(--z-header);
  border-right: 3px solid var(--c-accent);
  color: var(--c-white);
}

.site-header-inner {
  height: 100%;
  display: flex;
  flex-direction: column;
  padding: var(--space-5) 0 var(--space-4);
  overflow-y: auto;
}

/* ---------- 7. 品牌 ---------- */
.site-brand {
  padding: 0 var(--space-4);
  margin-bottom: var(--space-5);
}

.site-brand-link {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
}

.site-brand-link:hover {
  opacity: 0.92;
}

.site-brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: var(--c-accent);
  color: var(--c-primary);
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 20px;
  line-height: 1;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 10px), calc(100% - 10px) 100%, 0 100%);
  flex-shrink: 0;
  transition: transform var(--transition-fast);
}

.site-brand-link:hover .site-brand-mark {
  transform: rotate(-3deg) scale(1.04);
}

.site-brand-copy {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.site-brand-name {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 15px;
  line-height: 1.2;
  color: var(--c-white);
  letter-spacing: 0.02em;
  white-space: nowrap;
}

.site-brand-sub {
  font-family: var(--font-data);
  font-size: 10px;
  line-height: 1.2;
  color: var(--c-gold);
  letter-spacing: 0.1em;
  white-space: nowrap;
}

/* ---------- 8. 轨道导航 ---------- */
.site-nav {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  flex: 1;
  position: relative;
  counter-reset: navIndex;
}

.nav-list::before {
  content: "";
  position: absolute;
  left: 19px;
  top: 24px;
  bottom: 24px;
  width: 2px;
  background: linear-gradient(
    to bottom,
    var(--c-accent) 0%,
    rgba(255, 255, 255, 0.14) 20%,
    rgba(255, 255, 255, 0.14) 80%,
    var(--c-accent) 100%
  );
}

.nav-list-item {
  counter-increment: navIndex;
  position: relative;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: 11px var(--space-4) 11px 44px;
  color: rgba(255, 255, 255, 0.82);
  text-decoration: none;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: 0.04em;
  position: relative;
  transition: color var(--transition-fast), background var(--transition-fast);
}

.nav-link::before {
  content: "";
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  width: 11px;
  height: 11px;
  border-radius: 50%;
  border: 2px solid var(--c-accent);
  background: var(--c-primary);
  transition: background var(--transition-fast), transform var(--transition-fast), box-shadow var(--transition-fast);
}

.nav-link::after {
  content: "0" counter(navIndex);
  margin-left: auto;
  font-family: var(--font-data);
  font-size: 10px;
  color: rgba(255, 255, 255, 0.30);
  letter-spacing: 0.08em;
  padding-left: var(--space-2);
}

.nav-link:hover {
  color: var(--c-white);
  background: rgba(255, 255, 255, 0.05);
}

.nav-link:hover::before {
  background: var(--c-accent-soft);
  transform: translateY(-50%) scale(1.2);
}

.nav-link:active {
  transform: scale(0.99);
}

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

.nav-link[aria-current="page"]::before {
  background: var(--c-accent);
  box-shadow: 0 0 14px rgba(255, 122, 0, 0.65);
}

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

/* ---------- 9. CTA 按钮区 ---------- */
.nav-cta {
  margin: var(--space-4);
  align-self: stretch;
  justify-content: center;
}

/* ---------- 10. 移动端头部与抽屉 ---------- */
.nav-toggle {
  display: none;
  position: relative;
  z-index: var(--z-nav) + 1;
  width: 44px;
  height: 44px;
  padding: 10px;
  background: transparent;
  border: 2px solid transparent;
  border-radius: 0;
  cursor: pointer;
  transition: border-color var(--transition-fast);
}

.nav-toggle:hover {
  border-color: rgba(255, 122, 0, 0.6);
}

.nav-toggle:focus-visible {
  outline: 2px solid var(--c-accent);
  outline-offset: -2px;
}

.nav-toggle-box {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 100%;
  height: 100%;
}

.nav-toggle-bar {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--c-white);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.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);
}

@media (max-width: 1023px) {
  body {
    padding-left: 0;
    padding-top: var(--topbar-h);
  }

  #main-content {
    scroll-margin-top: calc(var(--topbar-h) + 16px);
  }

  .site-header {
    top: 0;
    left: 0;
    right: 0;
    bottom: auto;
    width: 100%;
    height: var(--topbar-h);
    border-right: none;
    border-bottom: 2px solid var(--c-accent);
  }

  .site-header-inner {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--space-3);
    overflow-y: visible;
  }

  .site-brand {
    padding: 0;
    margin-bottom: 0;
  }

  .site-brand-link {
    gap: var(--space-2);
  }

  .site-brand-mark {
    width: 36px;
    height: 36px;
    font-size: 16px;
    clip-path: polygon(0 0, 100% 0, 100% calc(100% - 8px), calc(100% - 8px) 100%, 0 100%);
  }

  .site-brand-name {
    font-size: 13px;
  }

  .site-brand-sub {
    font-size: 9px;
  }

  .nav-toggle {
    display: block;
    margin-left: var(--space-2);
  }

  .site-nav {
    position: fixed;
    top: var(--topbar-h);
    left: 0;
    bottom: 0;
    width: min(320px, 86vw);
    margin: 0;
    padding: var(--space-5) 0 var(--space-4);
    background: var(--c-primary);
    transform: translateX(-100%);
    transition: transform 0.3s ease;
    z-index: var(--z-nav);
    box-shadow: 8px 0 32px rgba(0, 0, 0, 0.35);
    border-right: 3px solid var(--c-accent);
    overflow-y: auto;
  }

  .site-nav[data-open="true"] {
    transform: translateX(0);
  }

  .nav-list::before {
    left: 19px;
  }

  .nav-cta {
    margin: var(--space-4);
  }
}

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

/* ---------- 11. 底部 ---------- */
.site-footer {
  background: var(--c-primary);
  color: rgba(255, 255, 255, 0.86);
  border-top: var(--border-w-thick) solid var(--c-accent);
  padding: var(--space-6) 0 0;
  margin-top: var(--space-7);
}

.site-footer-inner {
  max-width: calc(var(--container-w) + 48px);
  margin: 0 auto;
  padding: 0 var(--space-4);
}

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1.6fr 1.4fr;
  gap: var(--space-5);
  padding-bottom: var(--space-5);
}

.footer-brand-name {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 18px;
  color: var(--c-white);
  margin-bottom: var(--space-1);
}

.footer-brand-sub {
  font-family: var(--font-data);
  font-size: 11px;
  color: var(--c-gold);
  letter-spacing: 0.1em;
  margin-bottom: var(--space-3);
}

.footer-brand-brief {
  font-size: 14px;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.72);
  max-width: 340px;
}

.footer-col-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 13px;
  color: var(--c-white);
  letter-spacing: 0.08em;
  margin-bottom: var(--space-3);
  padding-bottom: var(--space-2);
  position: relative;
  text-transform: uppercase;
}

.footer-col-title::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 28px;
  height: 2px;
  background: var(--c-accent);
}

.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-links li {
  margin-bottom: var(--space-2);
}

.footer-links a {
  color: rgba(255, 255, 255, 0.72);
  text-decoration: none;
  font-size: 14px;
  border-bottom: 1px solid transparent;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

.footer-links a:hover {
  color: var(--c-accent);
  border-bottom-color: var(--c-accent);
}

.footer-contact-line {
  font-size: 14px;
  line-height: 1.6;
  color: rgba(255, 255, 255, 0.72);
  margin-bottom: var(--space-2);
}

.footer-trust {
  font-size: 13px;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.58);
  border-left: 2px solid var(--c-accent);
  padding-left: var(--space-3);
  font-family: var(--font-data);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.14);
  padding: var(--space-3) 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-2);
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--c-silver);
}

.footer-icp,
.footer-copy {
  margin: 0;
}

/* 页脚响应式 */
@media (max-width: 1023px) {
  .footer-top {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-5) var(--space-4);
  }
}

@media (max-width: 767px) {
  .site-footer {
    margin-top: var(--space-5);
    padding-top: var(--space-5);
  }

  .footer-top {
    grid-template-columns: 1fr;
    gap: var(--space-4);
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-1);
  }
}

/* ---------- 12. 通用按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 12px 24px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 14px;
  line-height: 1;
  text-decoration: none;
  cursor: pointer;
  border: 2px solid transparent;
  border-radius: 0;
  background: transparent;
  color: inherit;
  transition: background var(--transition-fast), color var(--transition-fast),
              transform var(--transition-fast), box-shadow var(--transition-fast),
              border-color var(--transition-fast);
}

.btn:active {
  transform: scale(0.97);
}

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

.btn-primary {
  background: var(--c-accent);
  color: var(--c-primary);
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  background: var(--c-accent-soft);
  color: var(--c-primary);
  transform: translate(-2px, -2px);
  box-shadow: var(--shadow-md);
}

.btn-gold {
  background: var(--c-gold);
  color: var(--c-primary);
  box-shadow: var(--shadow-sm);
}

.btn-gold:hover {
  background: #FFE44D;
  color: var(--c-primary);
  transform: translate(-2px, -2px);
  box-shadow: var(--shadow-md);
}

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

.btn-ghost:hover {
  background: rgba(255, 122, 0, 0.10);
  color: var(--c-accent);
}

.btn-sm {
  padding: 8px 16px;
  font-size: 12px;
}

.btn-lg {
  padding: 16px 32px;
  font-size: 16px;
}

/* ---------- 13. 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  list-style: none;
  margin: 0 0 var(--space-4);
  padding: 0;
  font-size: 13px;
  font-family: var(--font-display);
}

.breadcrumb li {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--c-silver);
}

.breadcrumb li + li::before {
  content: "→";
  color: var(--c-accent);
  font-family: var(--font-data);
  font-size: 12px;
}

.breadcrumb a {
  color: var(--c-primary);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

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

.breadcrumb li[aria-current="page"] {
  color: var(--c-accent);
  font-weight: 700;
}

/* ---------- 14. 网格系统 ---------- */
.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--space-4);
}

.col-span-1  { grid-column: span 1; }
.col-span-2  { grid-column: span 2; }
.col-span-3  { grid-column: span 3; }
.col-span-4  { grid-column: span 4; }
.col-span-5  { grid-column: span 5; }
.col-span-6  { grid-column: span 6; }
.col-span-7  { grid-column: span 7; }
.col-span-8  { grid-column: span 8; }
.col-span-9  { grid-column: span 9; }
.col-span-10 { grid-column: span 10; }
.col-span-11 { grid-column: span 11; }
.col-span-12 { grid-column: span 12; }

@media (max-width: 1023px) {
  .grid-12 {
    grid-template-columns: repeat(4, 1fr);
  }

  .col-span-1 { grid-column: span 1; }
  .col-span-2 { grid-column: span 2; }
  .col-span-3 { grid-column: span 3; }
  .col-span-4,
  .col-span-5,
  .col-span-6,
  .col-span-7,
  .col-span-8,
  .col-span-9,
  .col-span-10,
  .col-span-11,
  .col-span-12 {
    grid-column: span 4;
  }
}

@media (max-width: 767px) {
  .grid-12 {
    grid-template-columns: 1fr;
  }

  [class^="col-span-"] {
    grid-column: span 1;
  }
}

/* 非对称编辑网格：窄注释 + 宽内容 */
.content-grid {
  display: grid;
  grid-template-columns: minmax(200px, 0.6fr) minmax(0, 1.4fr);
  gap: var(--space-5);
  align-items: start;
}

@media (max-width: 767px) {
  .content-grid {
    grid-template-columns: 1fr;
    gap: var(--space-3);
  }
}

.note-column {
  border-left: 3px solid var(--c-accent);
  padding-left: var(--space-4);
  font-size: 14px;
  line-height: 1.7;
  color: var(--c-ink);
}

.wide-column {
  min-width: 0;
}

/* ---------- 15. 标题与索引 ---------- */
.heading-xl {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(40px, 6vw, 72px);
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--c-primary);
}

.heading-lg {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(28px, 4vw, 44px);
  line-height: 1.12;
  letter-spacing: -0.01em;
  color: var(--c-primary);
}

.display-title {
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(72px, 10vw, 120px);
  line-height: 0.88;
  letter-spacing: -0.04em;
  color: var(--c-primary);
}

.section-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(22px, 3vw, 32px);
  line-height: 1.2;
  color: var(--c-primary);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-3);
  position: relative;
}

.section-title::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 56px;
  height: 4px;
  background: var(--c-accent);
}

.index-label {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-data);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--c-accent);
  margin-bottom: var(--space-3);
}

.index-label::before {
  content: "";
  width: 24px;
  height: 2px;
  background: var(--c-accent);
  display: inline-block;
  flex-shrink: 0;
}

/* ---------- 16. 卡片 ---------- */
.card {
  background: var(--c-paper);
  border: var(--border-w) solid var(--c-primary);
  box-shadow: var(--shadow-sm);
  padding: var(--space-4);
  transition: box-shadow var(--transition-fast), transform var(--transition-fast);
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translate(-2px, -2px);
}

.card-header {
  padding-bottom: var(--space-3);
  margin-bottom: var(--space-3);
  border-bottom: 1px solid var(--c-silver);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
}

.card-body {
  font-size: 15px;
  line-height: 1.65;
}

.card-header + .card-body {
  margin-top: 0;
}

/* ---------- 17. 标签 ---------- */
.tag {
  display: inline-block;
  padding: 4px 12px;
  font-family: var(--font-data);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  border: 1px solid;
  line-height: 1.4;
  vertical-align: middle;
}

.tag-orange {
  color: var(--c-accent);
  border-color: var(--c-accent);
  background: rgba(255, 122, 0, 0.06);
}

.tag-gold {
  color: var(--c-gold);
  border-color: var(--c-gold);
  background: rgba(255, 215, 0, 0.08);
}

.tag-green {
  color: var(--c-green);
  border-color: var(--c-green);
  background: rgba(47, 163, 107, 0.06);
}

.tag-red {
  color: var(--c-red);
  border-color: var(--c-red);
  background: rgba(228, 87, 46, 0.06);
}

/* ---------- 18. 数据值 ---------- */
.data-value {
  font-family: var(--font-data);
  font-size: 16px;
  font-weight: 700;
  color: var(--c-accent);
  letter-spacing: 0.02em;
  line-height: 1.4;
}

/* ---------- 19. 分隔线与装饰 ---------- */
.divider-rule {
  height: 1px;
  background: linear-gradient(to right, var(--c-accent) 0%, var(--c-accent) 80px, var(--c-silver) 80px, var(--c-silver) 100%);
  border: none;
  margin: var(--space-5) 0;
}

.speed-lines {
  height: 28px;
  position: relative;
  overflow: hidden;
}

.speed-lines::before {
  content: "";
  position: absolute;
  top: 50%;
  left: 0;
  width: 100%;
  height: 2px;
  transform: translateY(-50%);
  background: repeating-linear-gradient(
    -25deg,
    var(--c-accent) 0 18px,
    transparent 18px 28px
  );
  opacity: 0.65;
}

.speed-lines--blue::before {
  background: repeating-linear-gradient(
    -25deg,
    var(--c-primary) 0 18px,
    transparent 18px 28px
  );
}

.corner-cut {
  clip-path: polygon(
    0 0,
    calc(100% - 24px) 0,
    100% 24px,
    100% 100%,
    24px 100%,
    0 calc(100% - 24px)
  );
}

.corner-cut--sm {
  clip-path: polygon(
    0 0,
    calc(100% - 12px) 0,
    100% 12px,
    100% 100%,
    12px 100%,
    0 calc(100% - 12px)
  );
}

/* ---------- 20. 图片占位框架 ---------- */
.img-frame {
  position: relative;
  display: block;
  background: var(--c-primary-light);
  border: var(--border-w) solid var(--c-primary);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  min-height: 120px;
}

.img-frame::before {
  content: "IMG";
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-data);
  font-size: 14px;
  font-weight: 400;
  letter-spacing: 0.3em;
  color: rgba(255, 255, 255, 0.55);
}

.img-frame img {
  position: relative;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 1;
}

.img-frame-16x9 {
  aspect-ratio: 16 / 9;
}

.img-frame-4x3 {
  aspect-ratio: 4 / 3;
}

.img-frame-1x1 {
  aspect-ratio: 1 / 1;
}

/* ---------- 21. 滚动显现协议 ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

[data-reveal][data-reveal-delay="1"] { transition-delay: 0.08s; }
[data-reveal][data-reveal-delay="2"] { transition-delay: 0.16s; }
[data-reveal][data-reveal-delay="3"] { transition-delay: 0.24s; }
[data-reveal][data-reveal-delay="4"] { transition-delay: 0.32s; }

/* ---------- 22. 工具类 ---------- */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.text-primary { color: var(--c-primary); }
.text-accent { color: var(--c-accent); }
.text-gold { color: var(--c-gold); }
.text-silver { color: var(--c-silver); }
.text-green { color: var(--c-green); }
.text-red { color: var(--c-red); }

.bg-primary { background: var(--c-primary); }
.bg-accent { background: var(--c-accent); }
.bg-paper { background: var(--c-paper); }
.bg-white { background: var(--c-white); }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--space-1); }
.mt-2 { margin-top: var(--space-2); }
.mt-3 { margin-top: var(--space-3); }
.mt-4 { margin-top: var(--space-4); }
.mt-5 { margin-top: var(--space-5); }
.mt-6 { margin-top: var(--space-6); }
.mt-7 { margin-top: var(--space-7); }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--space-1); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-3 { margin-bottom: var(--space-3); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-5 { margin-bottom: var(--space-5); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-7 { margin-bottom: var(--space-7); }

.px-3 { padding-left: var(--space-3); padding-right: var(--space-3); }
.px-4 { padding-left: var(--space-4); padding-right: var(--space-4); }
.py-4 { padding-top: var(--space-4); padding-bottom: var(--space-4); }
.py-5 { padding-top: var(--space-5); padding-bottom: var(--space-5); }
.py-6 { padding-top: var(--space-6); padding-bottom: var(--space-6); }

.text-center { text-align: center; }
.text-right { text-align: right; }
.flex { display: flex; }
.flex-col { display: flex; flex-direction: column; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.flex-wrap { flex-wrap: wrap; }
.flex-none { flex: none; }

/* ---------- 23. 焦点可见性 ---------- */
:focus-visible {
  outline: 2px solid var(--c-accent);
  outline-offset: 3px;
}

/* ---------- 24. 减少动态偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

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

  .skip-link {
    transition: none;
  }

  .site-nav {
    transition: none;
  }

  .nav-toggle-bar {
    transition: none;
  }
}

/* ---------- 25. 打印样式 ---------- */
@media print {
  .site-header,
  .site-footer,
  .nav-toggle {
    display: none !important;
  }

  body {
    padding-left: 0;
    padding-top: 0;
    background: var(--c-white);
    color: var(--c-ink);
  }

  #main-content {
    margin: 0;
  }
}