/* ==========================================================================
   乐橙注册 · /assets/site.css
   共享外壳样式：蓝图档案柜体系
   暖纸白底 + 深墨蓝信息层 + 暖橙行动色 + 状态青绿
   ========================================================================== */

/* 1. 变量 ---------------------------------------------------------------- */
:root {
  --c-orange: #FF6A1A;
  --c-amber: #FFA13C;
  --c-burnt: #C2461A;
  --c-ink: #0E1B2E;
  --c-ink-2: #1E3350;
  --c-paper: #F6F2EA;
  --c-paper-2: #E5DFD2;
  --c-mist: #8C99A8;
  --c-teal: #0F9C77;
  --c-white: #FFFFFF;

  --rule: rgba(14, 27, 46, 0.12);
  --rule-soft: rgba(14, 27, 46, 0.07);
  --rule-invert: rgba(246, 242, 234, 0.14);

  --font-sans: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, "Courier New", monospace;

  --fs-display: clamp(56px, 9vw, 132px);
  --fs-section: clamp(24px, 3vw, 40px);
  --fs-index: 11px;
  --fs-body: 17px;
  --lh-body: 1.85;

  --wrap: 1280px;
  --gutter: clamp(20px, 4vw, 56px);

  --shadow-layer: 6px 6px 0 rgba(14, 27, 46, 0.08);
  --shadow-layer-hover: 8px 8px 0 rgba(14, 27, 46, 0.1);
  --ease: cubic-bezier(0.22, 1, 0.36, 1);

  --header-h: 108px;
}

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 20px);
}

body {
  margin: 0;
  background-color: var(--c-paper);
  background-image:
    linear-gradient(to right, rgba(14, 27, 46, 0.045) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(14, 27, 46, 0.045) 1px, transparent 1px);
  background-size: 64px 64px;
  background-position: -1px -1px;
  color: var(--c-ink);
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  font-weight: 400;
  line-height: var(--lh-body);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body.nav-open { overflow: hidden; }

h1, h2, h3, h4, h5, h6 { margin: 0; line-height: 1.25; font-weight: 800; letter-spacing: -0.01em; }
p { margin: 0 0 1em; }
p:last-child { margin-bottom: 0; }
ul, ol { margin: 0; padding: 0; }
img, svg, video { display: block; max-width: 100%; height: auto; }
button { font: inherit; color: inherit; }
table { border-collapse: collapse; }

a { color: inherit; }

::selection { background: rgba(255, 106, 26, 0.28); color: var(--c-ink); }

:focus-visible {
  outline: 2px solid var(--c-orange);
  outline-offset: 3px;
  border-radius: 1px;
}

/* 3. 布局基础 ------------------------------------------------------------ */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  position: relative;
  padding-block: clamp(40px, 6vw, 88px);
}

.section + .section { border-top: 1px solid var(--rule); }

.grid { display: grid; gap: clamp(16px, 2vw, 28px); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }

@media (max-width: 900px) {
  .grid--2, .grid--3, .grid--12 { grid-template-columns: minmax(0, 1fr); }
}

/* 4. 跳过链接 ------------------------------------------------------------ */
.skip-link {
  position: absolute;
  left: 12px;
  top: -72px;
  z-index: 200;
  background: var(--c-orange);
  color: #1B0A02;
  padding: 11px 18px;
  border-radius: 2px;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  box-shadow: 3px 3px 0 rgba(14, 27, 46, 0.35);
  transition: top 0.22s var(--ease);
}
.skip-link:focus { top: 12px; }

/* 5. 页头 ---------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: var(--c-ink);
  color: var(--c-paper);
  border-bottom: 1px solid var(--rule-invert);
  box-shadow: 0 12px 32px rgba(9, 18, 32, 0.22);
}

.site-header::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(246, 242, 234, 0.05) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(246, 242, 234, 0.05) 1px, transparent 1px);
  background-size: 72px 72px;
}

.scroll-progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  z-index: 3;
  height: 2px;
  width: 0%;
  background: linear-gradient(90deg, var(--c-orange), var(--c-amber));
  transition: width 0.12s linear;
}

/* 5a. 上层信息条 */
.header-utility {
  position: relative;
  z-index: 1;
  border-bottom: 1px solid rgba(246, 242, 234, 0.11);
}

.header-utility__inner {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 9px var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.header-tagline {
  margin: 0;
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--c-mist);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.utility-nav {
  display: flex;
  align-items: center;
  gap: 22px;
  flex: 0 0 auto;
}

.utility-nav a {
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: rgba(246, 242, 234, 0.72);
  text-decoration: none;
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
  transition: color 0.22s var(--ease), border-color 0.22s var(--ease);
}
.utility-nav a:hover,
.utility-nav a:focus-visible { color: var(--c-amber); border-bottom-color: var(--c-amber); }

/* 5b. 下层主导航行 */
.header-main { position: relative; z-index: 1; }

.header-main__inner {
  position: relative;
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 14px var(--gutter);
  display: flex;
  align-items: center;
  gap: clamp(18px, 3vw, 44px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  text-decoration: none;
  color: inherit;
}

.brand__mark {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  background: var(--c-orange);
  color: #1B0A02;
  border-radius: 2px;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.02em;
  box-shadow: 3px 3px 0 rgba(255, 161, 60, 0.4);
  transition: transform 0.3s var(--ease), box-shadow 0.3s var(--ease);
}
.brand:hover .brand__mark { transform: translate(-2px, -2px); box-shadow: 5px 5px 0 rgba(255, 161, 60, 0.5); }

.brand__text { display: flex; flex-direction: column; gap: 3px; }

.brand__name {
  font-size: 19px;
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1;
  color: #FFFFFF;
}

.brand__sub {
  font-family: var(--font-mono);
  font-size: 9.5px;
  font-weight: 500;
  letter-spacing: 0.22em;
  line-height: 1;
  color: var(--c-mist);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  margin-left: auto;
  padding: 9px 13px;
  background: transparent;
  border: 1px solid rgba(246, 242, 234, 0.3);
  border-radius: 2px;
  color: var(--c-paper);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.1em;
  cursor: pointer;
  transition: border-color 0.22s var(--ease), color 0.22s var(--ease);
}
.nav-toggle:hover { border-color: var(--c-amber); color: var(--c-amber); }

.nav-toggle__bars {
  position: relative;
  display: block;
  width: 18px;
  height: 10px;
}
.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  background: currentColor;
  transition: transform 0.3s var(--ease);
}
.nav-toggle__bars::before { top: 0; }
.nav-toggle__bars::after { bottom: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { transform: translateY(4px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { transform: translateY(-4px) rotate(-45deg); }

.primary-nav {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 30px);
  margin-left: auto;
}

.primary-nav__list {
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.6vw, 26px);
  list-style: none;
  margin: 0;
  padding: 0;
}

.primary-nav__list a {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  padding: 10px 2px;
  font-size: clamp(13px, 1.05vw, 14.5px);
  font-weight: 500;
  letter-spacing: 0.02em;
  color: rgba(246, 242, 234, 0.8);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.24s var(--ease);
}

.primary-nav__list a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 100%;
  bottom: 5px;
  height: 2px;
  background: var(--c-orange);
  transition: right 0.3s var(--ease);
}

.primary-nav__list a:hover { color: #FFFFFF; }
.primary-nav__list a:hover::after { right: 0; }

.primary-nav__list a[aria-current="page"] { color: #FFFFFF; }
.primary-nav__list a[aria-current="page"] .nav-index { color: var(--c-orange); }
.primary-nav__list a[aria-current="page"]::after { right: 0; }

.nav-index {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--c-mist);
  transition: color 0.24s var(--ease);
}

/* 5c. 移动端导航 */
@media (max-width: 1120px) {
  .nav-toggle { display: inline-flex; }

  .primary-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    z-index: 4;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    margin-left: 0;
    padding: 8px 0 20px;
    max-height: calc(100vh - var(--header-h));
    overflow-y: auto;
    background: var(--c-ink-2);
    border-top: 1px solid var(--rule-invert);
    box-shadow: 0 26px 44px rgba(6, 12, 22, 0.5);
  }

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

  .primary-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .primary-nav__list li { border-bottom: 1px solid rgba(246, 242, 234, 0.1); }

  .primary-nav__list a {
    padding: 15px var(--gutter);
    font-size: 15px;
    white-space: normal;
  }

  .primary-nav__list a::after { display: none; }

  .primary-nav__list a[aria-current="page"] {
    background: rgba(255, 106, 26, 0.14);
    box-shadow: inset 3px 0 0 var(--c-orange);
  }

  .header-cta {
    margin: 18px var(--gutter) 0;
    justify-content: center;
  }
}

/* 6. 通用按钮 ------------------------------------------------------------ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 20px;
  border: 1px solid transparent;
  border-radius: 2px;
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.02em;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
  transition: transform 0.25s var(--ease), background-color 0.25s var(--ease),
              box-shadow 0.25s var(--ease), border-color 0.25s var(--ease), color 0.25s var(--ease);
}

.btn--primary {
  background: var(--c-orange);
  color: #1B0A02;
  box-shadow: 3px 3px 0 rgba(194, 70, 26, 0.55);
}
.btn--primary:hover {
  background: var(--c-amber);
  transform: translateY(-2px);
  box-shadow: 4px 4px 0 rgba(194, 70, 26, 0.6);
}

.btn--outline {
  background: transparent;
  border-color: rgba(14, 27, 46, 0.45);
  color: var(--c-ink);
}
.btn--outline:hover {
  background: var(--c-ink);
  border-color: var(--c-ink);
  color: var(--c-paper);
  transform: translateY(-2px);
}

.btn--ghost {
  background: transparent;
  border-color: rgba(246, 242, 234, 0.35);
  color: var(--c-paper);
}
.btn--ghost:hover {
  border-color: var(--c-amber);
  color: var(--c-amber);
  transform: translateY(-2px);
}

.header-cta { flex: 0 0 auto; white-space: nowrap; }

/* 7. 页脚 ---------------------------------------------------------------- */
.site-footer {
  position: relative;
  background: var(--c-ink);
  color: rgba(246, 242, 234, 0.78);
  border-top: 1px solid var(--rule-invert);
  overflow: hidden;
}

.site-footer::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(246, 242, 234, 0.045) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(246, 242, 234, 0.045) 1px, transparent 1px);
  background-size: 72px 72px;
}

.site-footer::after {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 88px;
  height: 3px;
  background: var(--c-orange);
  z-index: 2;
}

.footer-top {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: clamp(40px, 6vw, 72px) var(--gutter) clamp(26px, 4vw, 44px);
  display: grid;
  gap: clamp(28px, 4vw, 56px);
  grid-template-columns: minmax(0, 1fr);
}

@media (min-width: 900px) {
  .footer-top { grid-template-columns: minmax(220px, 0.9fr) minmax(0, 2.6fr); }
}

.footer-brand { display: flex; flex-direction: column; gap: 16px; }

.footer-note {
  margin: 0;
  max-width: 34ch;
  font-size: 13.5px;
  line-height: 1.8;
  color: rgba(140, 153, 168, 0.95);
}
.footer-note--tight { margin-top: 14px; max-width: 26ch; }

.footer-cols {
  display: grid;
  gap: 26px 20px;
  grid-template-columns: minmax(0, 1fr);
}
@media (min-width: 520px) { .footer-cols { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (min-width: 1024px) { .footer-cols { grid-template-columns: repeat(4, minmax(0, 1fr)); } }

.footer-col { min-width: 0; }

.footer-col__title {
  margin: 0 0 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(246, 242, 234, 0.14);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--c-amber);
}

.footer-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-list a {
  font-size: 14px;
  line-height: 1.6;
  color: rgba(246, 242, 234, 0.76);
  text-decoration: none;
  transition: color 0.22s var(--ease), padding-left 0.22s var(--ease);
}
.footer-list a:hover,
.footer-list a:focus-visible { color: var(--c-orange); padding-left: 6px; }

.footer-list--contact li {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 10px;
  align-items: baseline;
}

.footer-key {
  font-family: var(--font-mono);
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.14em;
  color: var(--c-mist);
  padding-top: 2px;
}

.footer-val {
  font-size: 13.5px;
  line-height: 1.7;
  color: rgba(246, 242, 234, 0.82);
  word-break: break-word;
}

.footer-bottom {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 16px var(--gutter) 30px;
  border-top: 1px solid rgba(246, 242, 234, 0.12);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 24px;
}

.footer-meta {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  line-height: 1.6;
  color: rgba(140, 153, 168, 0.95);
}
.footer-meta--quiet { color: rgba(140, 153, 168, 0.8); }

/* 8. 章节标题体系 -------------------------------------------------------- */
.section-head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 10px 20px;
  align-items: baseline;
  margin-bottom: clamp(24px, 3vw, 40px);
}
@media (max-width: 640px) { .section-head { grid-template-columns: minmax(0, 1fr); gap: 8px; } }

.section-index {
  font-family: var(--font-mono);
  font-size: var(--fs-index);
  font-weight: 500;
  letter-spacing: 0.18em;
  color: var(--c-orange);
}

.section-title {
  margin: 0;
  font-size: var(--fs-section);
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.2;
  color: var(--c-ink);
}

/* 9. 卡片 / 标签 / 数字 / 引述 ------------------------------------------- */
.card {
  position: relative;
  background: var(--c-white);
  border: 1px solid var(--rule);
  border-radius: 2px;
  box-shadow: var(--shadow-layer);
  padding: clamp(18px, 2.4vw, 28px);
  transition: transform 0.3s var(--ease), box-shadow 0.3s var(--ease), border-color 0.3s var(--ease);
}
.card:hover {
  transform: translateY(-2px);
  border-color: rgba(255, 106, 26, 0.5);
  box-shadow: var(--shadow-layer-hover);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 10px;
  border: 1px solid var(--rule);
  border-radius: 2px;
  background: var(--c-paper);
  color: var(--c-ink-2);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  line-height: 1.3;
}
.tag--orange { background: rgba(255, 106, 26, 0.12); border-color: rgba(255, 106, 26, 0.42); color: var(--c-burnt); }
.tag--teal { background: rgba(15, 156, 119, 0.12); border-color: rgba(15, 156, 119, 0.42); color: #0B7458; }
.tag--ink { background: var(--c-ink); border-color: var(--c-ink); color: var(--c-paper); }

.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 500;
  letter-spacing: 0.01em;
}

.pull-quote {
  margin: 0;
  padding: 4px 0 4px 18px;
  border-left: 4px solid var(--c-orange);
  font-size: clamp(18px, 2vw, 23px);
  font-weight: 400;
  line-height: 1.6;
  color: var(--c-ink-2);
}

.link-inline {
  color: var(--c-burnt);
  text-decoration: none;
  border-bottom: 1px solid rgba(194, 70, 26, 0.35);
  transition: border-color 0.22s var(--ease), color 0.22s var(--ease);
}
.link-inline:hover { border-bottom-color: var(--c-burnt); color: var(--c-orange); }

/* 10. 面包屑 -------------------------------------------------------------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: var(--fs-index);
  font-weight: 500;
  letter-spacing: 0.14em;
  line-height: 1.6;
  color: var(--c-mist);
}
.breadcrumb a {
  color: var(--c-mist);
  text-decoration: none;
  transition: color 0.22s var(--ease);
}
.breadcrumb a:hover { color: var(--c-orange); }
.breadcrumb__sep { color: rgba(140, 153, 168, 0.55); }
.breadcrumb__current { color: var(--c-ink); }

/* 11. 表格 ---------------------------------------------------------------- */
.table-scroll {
  width: 100%;
  overflow-x: auto;
  border: 1px solid var(--rule);
  border-radius: 2px;
  background: var(--c-white);
  -webkit-overflow-scrolling: touch;
}

.data-table {
  width: 100%;
  min-width: 560px;
  background: var(--c-white);
  font-size: 14.5px;
  line-height: 1.65;
}
.data-table caption {
  caption-side: top;
  padding: 12px 14px;
  text-align: left;
  font-family: var(--font-mono);
  font-size: var(--fs-index);
  letter-spacing: 0.16em;
  color: var(--c-mist);
}
.data-table th,
.data-table td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--rule);
  text-align: left;
  vertical-align: top;
}
.data-table thead th {
  position: sticky;
  top: 0;
  z-index: 1;
  background: var(--c-ink-2);
  color: var(--c-paper);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.04em;
  white-space: nowrap;
}
.data-table tbody tr:nth-child(even) { background: var(--c-paper); }
.data-table tbody tr:last-child th,
.data-table tbody tr:last-child td { border-bottom: 0; }
.data-table .num,
.data-table th.num,
.data-table td.num { text-align: right; }

/* 12. 锚点索引条 ---------------------------------------------------------- */
.anchor-bar {
  position: sticky;
  top: calc(var(--header-h) + 12px);
  z-index: 40;
  display: flex;
  gap: 4px;
  overflow-x: auto;
  padding: 8px;
  background: rgba(246, 242, 234, 0.94);
  border: 1px solid var(--rule);
  border-radius: 2px;
  box-shadow: 0 8px 22px rgba(14, 27, 46, 0.07);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  -webkit-overflow-scrolling: touch;
}
.anchor-bar a {
  flex: 0 0 auto;
  padding: 7px 12px;
  border-radius: 2px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--c-ink-2);
  text-decoration: none;
  white-space: nowrap;
  transition: background-color 0.22s var(--ease), color 0.22s var(--ease);
}
.anchor-bar a:hover { background: rgba(255, 106, 26, 0.14); color: var(--c-burnt); }
.anchor-bar a[aria-current="true"] { background: var(--c-ink); color: var(--c-paper); }

/* 13. 图片容器基础规则 ---------------------------------------------------- */
.media-frame {
  position: relative;
  display: block;
  width: 100%;
  overflow: hidden;
  background: var(--c-white);
  border: 1px solid var(--rule);
  border-radius: 2px;
  box-shadow: var(--shadow-layer);
}
.media-frame img,
.media-frame svg { display: block; width: 100%; height: auto; }

.media-frame--16x9 { aspect-ratio: 16 / 9; }
.media-frame--4x3 { aspect-ratio: 4 / 3; }
.media-frame--1x1 { aspect-ratio: 1 / 1; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--wide { aspect-ratio: 21 / 9; }

.media-frame--16x9 img,
.media-frame--4x3 img,
.media-frame--1x1 img,
.media-frame--tall img,
.media-frame--wide img {
  height: 100%;
  object-fit: cover;
}

.media-frame__tag {
  position: absolute;
  left: 0;
  top: 0;
  z-index: 2;
  padding: 7px 10px;
  background: var(--c-ink);
  color: var(--c-paper);
  font-family: var(--font-mono);
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.14em;
}

.media-frame__placeholder {
  position: absolute;
  inset: 0;
  background-color: var(--c-paper-2);
  background-image:
    linear-gradient(135deg, rgba(14, 27, 46, 0.06) 25%, transparent 25%),
    linear-gradient(135deg, transparent 75%, rgba(14, 27, 46, 0.06) 75%);
  background-size: 22px 22px;
  background-position: 0 0, 11px 11px;
}

/* 14. 滚动显现 ------------------------------------------------------------ */
[data-reveal] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.44s var(--ease), transform 0.44s var(--ease);
  transition-delay: var(--reveal-delay, 0s);
}
[data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

/* 15. 降低动效 ------------------------------------------------------------ */
@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;
  }

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

  .scroll-progress { transition: none; }
}

/* 16. 小屏细节 ------------------------------------------------------------ */
@media (max-width: 640px) {
  .header-tagline { font-size: 11px; letter-spacing: 0.06em; }
  .utility-nav { gap: 14px; }
  .utility-nav a { font-size: 11.5px; }
  .brand__mark { width: 36px; height: 36px; font-size: 13.5px; }
  .brand__name { font-size: 17px; }
  .footer-list--contact li { grid-template-columns: minmax(0, 1fr); gap: 2px; }
  .footer-key { padding-top: 0; }
}