/* ============================================================
   欧博游艺 · 共享站点样式 /assets/site.css
   侧边轨道导航 + 堆叠面板 + 夜场竞技配色
   ============================================================ */

/* ---------- 1. reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; text-size-adjust: 100%; }
body, h1, h2, h3, h4, h5, p, ul, ol, li, figure, blockquote, dl, dd { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, svg, video { display: block; max-width: 100%; }
button { font: inherit; color: inherit; background: none; border: 0; }
a { color: inherit; text-decoration: none; }
table { border-collapse: collapse; width: 100%; }
hr { border: 0; }

/* ---------- 2. 变量 ---------- */
:root {
  /* 色板 */
  --ink: #0B1F1A;
  --panel: #101214;
  --deep: #07100D;
  --paper: #F3EFE4;
  --mist: #9AA7A1;
  --orange: #FF6A2A;
  --cyan: #35F2D0;
  --gold: #D9A441;

  /* 派生 */
  --paper-86: rgba(243, 239, 228, 0.86);
  --paper-70: rgba(243, 239, 228, 0.70);
  --paper-12: rgba(243, 239, 228, 0.12);
  --paper-08: rgba(243, 239, 228, 0.08);
  --cyan-08: rgba(53, 242, 208, 0.08);
  --cyan-50: rgba(53, 242, 208, 0.50);
  --orange-08: rgba(255, 106, 42, 0.08);
  --gold-50: rgba(217, 164, 65, 0.50);

  /* 排版 */
  --font-serif: "Noto Serif SC", "Songti SC", "SimSun", "STSong", serif;
  --font-sans: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "IBM Plex Mono", "JetBrains Mono", "SFMono-Regular", Consolas, monospace;

  /* 尺寸 */
  --rail: 104px;
  --max: 1360px;
  --gap: clamp(16px, 2.2vw, 32px);
  --pad-x: clamp(20px, 4.2vw, 64px);
  --radius: 2px;
}

/* ---------- 3. 基础排版 ---------- */
body {
  min-height: 100vh;
  background:
    radial-gradient(1200px 700px at 80% -12%, rgba(53, 242, 208, 0.09), transparent 62%),
    radial-gradient(900px 620px at 6% 108%, rgba(255, 106, 42, 0.08), transparent 66%),
    var(--ink);
  color: var(--paper-86);
  font-family: var(--font-sans);
  font-size: clamp(15px, 0.55vw + 13px, 17px);
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

p { max-width: 68ch; }

::selection { background: var(--orange); color: #160A02; }

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

#main-content { scroll-margin-top: 84px; }

/* ---------- 4. 容器与章节 ---------- */
.ob-main { display: block; }

.ob-shell {
  width: 100%;
  max-width: var(--max);
  margin-inline: auto;
  padding-inline: var(--pad-x);
}
.ob-shell--narrow { max-width: 900px; }

.ob-section {
  position: relative;
  padding-block: clamp(44px, 6.4vw, 104px);
}
.ob-section + .ob-section { border-top: 1px solid var(--paper-08); }

.ob-section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: clamp(24px, 3vw, 44px);
}

.ob-divider {
  height: 1px;
  border: 0;
  background: linear-gradient(90deg, var(--paper-12), transparent 85%);
  margin-block: clamp(20px, 3vw, 36px);
}

/* ---------- 5. 文字基元 ---------- */
.ob-eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--cyan);
}

.ob-display {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(34px, 5.2vw, 68px);
  line-height: 1.12;
  letter-spacing: 0.012em;
  color: var(--paper);
  max-width: 22ch;
}

.ob-title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(23px, 2.5vw, 36px);
  line-height: 1.28;
  letter-spacing: 0.02em;
  color: var(--paper);
}

.ob-panel-title {
  font-family: var(--font-sans);
  font-weight: 800;
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--paper);
  text-transform: uppercase;
}

.ob-lede {
  font-size: clamp(16px, 1.1vw, 18px);
  line-height: 1.8;
  color: var(--paper-70);
  max-width: 62ch;
}

.ob-data {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
  color: var(--paper);
}

/* ---------- 6. 按钮 ---------- */
.ob-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  padding: 0.85em 1.55em;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 14px;
  letter-spacing: 0.1em;
  line-height: 1.15;
  cursor: pointer;
  transition: background-color 0.22s ease, color 0.22s ease, border-color 0.22s ease, box-shadow 0.22s ease;
}

.ob-btn--solid {
  background: var(--orange);
  border-color: var(--orange);
  color: #180800;
}
.ob-btn--solid:hover { background: #ff8b57; border-color: #ff8b57; }
.ob-btn--solid:active { background: #e85a1c; border-color: #e85a1c; }

.ob-btn--ghost {
  background: rgba(243, 239, 228, 0.02);
  border-color: rgba(243, 239, 228, 0.28);
  color: var(--paper);
}
.ob-btn--ghost:hover {
  border-color: var(--cyan);
  color: var(--cyan);
  background: var(--cyan-08);
}

.ob-btn--quiet {
  padding: 0.35em 0;
  border: 0;
  border-bottom: 1px solid rgba(53, 242, 208, 0.42);
  border-radius: 0;
  color: var(--cyan);
  font-size: 13px;
  letter-spacing: 0.14em;
}
.ob-btn--quiet:hover { color: var(--paper); border-bottom-color: var(--orange); }

.ob-btn--rail {
  width: 100%;
  padding: 11px 4px;
  font-size: 11.5px;
  letter-spacing: 0.1em;
}

/* ---------- 7. 面包屑 ---------- */
.ob-crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6em;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.14em;
  color: var(--mist);
  padding-block: 22px;
}
.ob-crumbs__link { color: var(--paper-70); transition: color 0.2s ease; }
.ob-crumbs__link:hover { color: var(--cyan); }
.ob-crumbs__sep { color: rgba(243, 239, 228, 0.26); }
.ob-crumbs__current { color: var(--paper); }

/* ---------- 8. 栅格 ---------- */
.ob-grid { display: grid; gap: var(--gap); }
.ob-grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.ob-grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.ob-grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

/* ---------- 9. 面板 / 标签 ---------- */
.ob-panel {
  position: relative;
  padding: clamp(20px, 2.3vw, 34px);
  background: linear-gradient(178deg, rgba(16, 18, 20, 0.97), rgba(16, 18, 20, 0.80));
  border: 1px solid rgba(243, 239, 228, 0.10);
  border-radius: var(--radius);
  box-shadow: 0 22px 60px -40px rgba(0, 0, 0, 0.9);
}
.ob-panel::before {
  content: "";
  position: absolute;
  inset: 7px;
  border: 1px solid rgba(243, 239, 228, 0.05);
  pointer-events: none;
}

.ob-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.4em;
  padding: 0.34em 0.72em;
  border: 1px solid rgba(243, 239, 228, 0.22);
  border-radius: 1px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--paper-86);
  white-space: nowrap;
}
.ob-tag--cyan { color: var(--cyan); border-color: var(--cyan-50); background: var(--cyan-08); }
.ob-tag--orange { color: var(--orange); border-color: rgba(255, 106, 42, 0.55); background: var(--orange-08); }
.ob-tag--gold { color: var(--gold); border-color: var(--gold-50); background: rgba(217, 164, 65, 0.09); }

/* ---------- 10. 图像容器（页面阶段填充） ---------- */
.ob-media {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: 1px solid rgba(243, 239, 228, 0.13);
  border-radius: var(--radius);
  background:
    linear-gradient(140deg, rgba(53, 242, 208, 0.13), rgba(16, 18, 20, 0.94) 46%, rgba(255, 106, 42, 0.12));
  isolation: isolate;
}
.ob-media--wide { aspect-ratio: 21 / 9; }
.ob-media--tall { aspect-ratio: 3 / 4; }
.ob-media--square { aspect-ratio: 1 / 1; }

.ob-media__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.92) contrast(1.06);
}

.ob-media__frame {
  position: absolute;
  inset: 10px;
  border: 1px solid rgba(243, 239, 228, 0.14);
  pointer-events: none;
  z-index: 1;
}
.ob-media__frame::after {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 46px;
  height: 2px;
  background: var(--cyan);
  box-shadow: 0 0 12px rgba(53, 242, 208, 0.55);
}

.ob-media__cap {
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 2;
  padding: 12px 15px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.15em;
  color: rgba(243, 239, 228, 0.84);
  background: linear-gradient(0deg, rgba(7, 16, 13, 0.88), transparent);
  width: 100%;
}

/* ---------- 11. 横向记录带 ---------- */
.ob-band {
  display: flex;
  gap: 12px;
  overflow-x: auto;
  overscroll-behavior-x: contain;
  scroll-snap-type: x proximity;
  padding-block: 6px 12px;
  scrollbar-width: thin;
  scrollbar-color: rgba(53, 242, 208, 0.45) transparent;
}
.ob-band > * {
  flex: 0 0 auto;
  scroll-snap-align: start;
}
.ob-band::-webkit-scrollbar { height: 4px; }
.ob-band::-webkit-scrollbar-track { background: rgba(243, 239, 228, 0.06); }
.ob-band::-webkit-scrollbar-thumb { background: rgba(53, 242, 208, 0.42); }

/* ============================================================
   12. 头部：桌面侧边轨道
   ============================================================ */
.ob-head {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: var(--rail);
  display: flex;
  flex-direction: column;
  background: linear-gradient(180deg, #0A1714 0%, var(--deep) 44%, #050C0A 100%);
  border-right: 1px solid var(--paper-12);
  z-index: 90;
  overflow: hidden;
}

.ob-skip {
  position: fixed;
  top: 10px;
  left: calc(var(--rail) + 12px);
  z-index: 200;
  padding: 10px 18px;
  background: var(--cyan);
  color: #04120F;
  font-weight: 700;
  font-size: 13px;
  letter-spacing: 0.06em;
  border-radius: var(--radius);
  transform: translateY(-160%);
  transition: transform 0.2s ease;
}
.ob-skip:focus { transform: translateY(0); }

.ob-head__bar {
  flex: 0 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 9px;
  padding: 22px 8px 18px;
  border-bottom: 1px solid var(--paper-08);
}

.ob-head__brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  text-align: center;
}

.ob-head__mark {
  position: relative;
  display: block;
  width: 26px;
  height: 26px;
  border: 1px solid var(--cyan-50);
  background: linear-gradient(135deg, rgba(53, 242, 208, 0.30), rgba(255, 106, 42, 0.18));
  box-shadow: 0 0 20px rgba(53, 242, 208, 0.26);
}
.ob-head__mark::after {
  content: "";
  position: absolute;
  inset: 6px;
  border: 1px solid rgba(243, 239, 228, 0.55);
}

.ob-head__name {
  font-family: var(--font-sans);
  font-weight: 800;
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--paper);
}

.ob-head__sub {
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.24em;
  color: var(--mist);
}

/* 导航轨道 */
.ob-nav {
  flex: 1 1 auto;
  min-height: 0;
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  padding: 14px 0 8px;
  scrollbar-width: none;
}
.ob-nav::-webkit-scrollbar { width: 0; height: 0; }

.ob-nav__utility {
  margin: 0 10px 12px;
  padding: 0 4px 12px;
  border-bottom: 1px solid rgba(243, 239, 228, 0.07);
  font-family: var(--font-mono);
  font-size: 9px;
  line-height: 2;
  letter-spacing: 0.08em;
  color: rgba(154, 167, 161, 0.78);
  text-align: center;
  max-width: none;
}

.ob-nav__list { display: flex; flex-direction: column; gap: 2px; }
.ob-nav__item { display: flex; }

.ob-nav__link {
  position: relative;
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  padding: 9px 4px;
  color: rgba(243, 239, 228, 0.70);
  transition: color 0.2s ease, background-color 0.2s ease;
}
.ob-nav__link::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  width: 2px;
  height: 0;
  background: var(--cyan);
  transform: translateY(-50%);
  transition: height 0.24s ease, background-color 0.2s ease;
}
.ob-nav__link:hover,
.ob-nav__link:focus-visible {
  color: var(--paper);
  background: var(--cyan-08);
}
.ob-nav__link:hover::before,
.ob-nav__link:focus-visible::before { height: 62%; }

.ob-nav__num {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  color: rgba(154, 167, 161, 0.8);
  transition: color 0.2s ease;
}

.ob-nav__text {
  writing-mode: vertical-rl;
  text-orientation: mixed;
  font-size: 12px;
  letter-spacing: 0.1em;
  line-height: 1.1;
}

.ob-nav__link[aria-current="page"] {
  color: var(--orange);
  background: var(--orange-08);
}
.ob-nav__link[aria-current="page"] .ob-nav__num { color: var(--orange); }
.ob-nav__link[aria-current="page"]::before {
  height: 80%;
  background: var(--orange);
  box-shadow: 0 0 10px rgba(255, 106, 42, 0.6);
}

.ob-nav__foot {
  flex: 0 0 auto;
  padding: 12px 10px 18px;
  border-top: 1px solid var(--paper-08);
}

/* 移动端开关（桌面隐藏） */
.ob-nav-toggle { display: none; }

/* 遮罩（桌面不参与） */
.ob-scrim { display: none; }

/* 进度线：桌面为轨道右缘竖线 */
.ob-progress {
  position: absolute;
  right: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: rgba(243, 239, 228, 0.06);
  pointer-events: none;
  z-index: 2;
}
.ob-progress__bar {
  display: block;
  width: 100%;
  height: calc(var(--p, 0) * 100%);
  background: linear-gradient(180deg, var(--cyan), var(--orange));
  box-shadow: 0 0 10px rgba(53, 242, 208, 0.5);
  transition: height 0.12s linear;
}

/* ============================================================
   13. 页脚
   ============================================================ */
.ob-foot {
  position: relative;
  overflow: hidden;
  margin-top: clamp(56px, 8vw, 112px);
  border-top: 1px solid var(--paper-12);
  background: linear-gradient(180deg, #09130F 0%, var(--deep) 42%, #050B09 100%);
  color: var(--paper-70);
}
.ob-foot::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(640px 300px at 90% 0%, rgba(53, 242, 208, 0.11), transparent 70%),
    radial-gradient(520px 280px at 4% 100%, rgba(255, 106, 42, 0.10), transparent 72%);
}

.ob-foot__inner {
  position: relative;
  z-index: 1;
  max-width: var(--max);
  margin-inline: auto;
  padding: clamp(40px, 5vw, 72px) var(--pad-x) 26px;
}

.ob-foot__top {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 20px;
  padding-bottom: clamp(24px, 3vw, 38px);
  border-bottom: 1px solid var(--paper-12);
}

.ob-foot__brand {
  display: flex;
  flex-direction: column;
  gap: 10px;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(24px, 3vw, 38px);
  line-height: 1.2;
  letter-spacing: 0.04em;
  color: var(--paper);
  max-width: none;
}

.ob-foot__brandsub {
  font-family: var(--font-sans);
  font-weight: 400;
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

.ob-foot__line {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.28em;
  color: var(--gold);
  max-width: none;
}

.ob-foot__grid {
  display: grid;
  grid-template-columns: 1.1fr 1.25fr 1fr;
  gap: clamp(24px, 4vw, 64px);
  padding-block: clamp(28px, 4vw, 46px);
}

.ob-foot__col { min-width: 0; }

.ob-foot__h {
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--cyan);
}

.ob-foot__list { display: flex; flex-direction: column; gap: 9px; }

.ob-foot__link {
  display: inline-block;
  font-size: 14px;
  color: rgba(243, 239, 228, 0.78);
  border-bottom: 1px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}
.ob-foot__link:hover { color: var(--paper); border-bottom-color: var(--orange); }

.ob-foot__data {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--paper);
}

.ob-foot__addr {
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--paper-70);
}

.ob-foot__note {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px dashed rgba(243, 239, 228, 0.16);
  font-size: 12px;
  line-height: 1.75;
  color: var(--mist);
  max-width: 36ch;
}

.ob-foot__base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding-top: 20px;
  border-top: 1px solid var(--paper-12);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: rgba(154, 167, 161, 0.92);
}
.ob-foot__copy, .ob-foot__icp { max-width: none; }
.ob-foot__icp { color: rgba(243, 239, 228, 0.58); }

/* ============================================================
   14. 显现动效
   ============================================================ */
.ob-js [data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.62s ease, transform 0.62s ease;
  will-change: opacity, transform;
}
.ob-js [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

/* ============================================================
   15. 响应式
   ============================================================ */
@media (min-width: 1000px) {
  body { padding-left: var(--rail); }
}

@media (max-height: 800px) and (min-width: 1000px) {
  .ob-nav__utility { display: none; }
  .ob-head__sub { display: none; }
  .ob-head__bar { padding-block: 16px 14px; }
}

@media (max-width: 1100px) {
  .ob-grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 900px) {
  .ob-grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .ob-foot__grid { grid-template-columns: 1fr 1fr; }
  .ob-foot__col:last-child { grid-column: 1 / -1; }
}

@media (max-width: 999px) {
  :root { --rail: 0px; }

  html.ob-lock, html.ob-lock body { overflow: hidden; }

  body { padding-left: 0; padding-top: 64px; }

  .ob-skip { left: 12px; }

  .ob-head {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: auto;
    width: auto;
    height: 64px;
    flex-direction: row;
    align-items: center;
    overflow: visible;
    background: rgba(7, 16, 13, 0.94);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    border-right: 0;
    border-bottom: 1px solid var(--paper-12);
    z-index: 120;
  }

  .ob-head__bar {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    width: 100%;
    height: 64px;
    padding: 0 16px;
    border-bottom: 0;
  }

  .ob-head__brand {
    flex-direction: row;
    align-items: center;
    gap: 10px;
    text-align: left;
  }
  .ob-head__mark { width: 22px; height: 22px; }
  .ob-head__mark::after { inset: 5px; }
  .ob-head__name { font-size: 14px; letter-spacing: 0.12em; }
  .ob-head__sub { display: none; }

  .ob-nav-toggle {
    display: inline-flex;
    align-items: center;
    gap: 9px;
    padding: 9px 12px;
    border: 1px solid rgba(243, 239, 228, 0.24);
    border-radius: var(--radius);
    color: var(--paper);
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: 0.16em;
    cursor: pointer;
    transition: border-color 0.2s ease, color 0.2s ease, background-color 0.2s ease;
  }
  .ob-nav-toggle:hover { border-color: var(--cyan); color: var(--cyan); background: var(--cyan-08); }

  .ob-nav-toggle__bars {
    display: inline-flex;
    flex-direction: column;
    justify-content: space-between;
    width: 16px;
    height: 12px;
  }
  .ob-nav-toggle__bars i {
    display: block;
    height: 2px;
    width: 100%;
    background: currentColor;
    transform-origin: center;
    transition: transform 0.26s ease, opacity 0.2s ease;
  }
  .ob-head[data-open="true"] .ob-nav-toggle__bars i:nth-child(1) { transform: translateY(5px) rotate(45deg); }
  .ob-head[data-open="true"] .ob-nav-toggle__bars i:nth-child(2) { opacity: 0; }
  .ob-head[data-open="true"] .ob-nav-toggle__bars i:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

  .ob-nav {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: min(84vw, 340px);
    padding: 84px 22px 28px;
    overflow-y: auto;
    background: linear-gradient(180deg, #0C1916, var(--deep));
    border-left: 1px solid rgba(243, 239, 228, 0.14);
    box-shadow: -28px 0 70px rgba(0, 0, 0, 0.62);
    transform: translateX(102%);
    visibility: hidden;
    transition: transform 0.34s cubic-bezier(0.4, 0, 0.2, 1), visibility 0.34s;
    z-index: 130;
  }
  .ob-head[data-open="true"] .ob-nav {
    transform: translateX(0);
    visibility: visible;
  }

  .ob-nav__utility {
    margin: 0 0 14px;
    padding: 0 6px 14px;
    font-size: 10px;
    line-height: 2;
    text-align: left;
    letter-spacing: 0.14em;
  }

  .ob-nav__list { gap: 0; }

  .ob-nav__link {
    flex-direction: row;
    align-items: baseline;
    justify-content: flex-start;
    gap: 14px;
    padding: 16px 6px;
    border-bottom: 1px solid var(--paper-08);
  }
  .ob-nav__link::before {
    left: 0;
    top: auto;
    bottom: -1px;
    width: 0;
    height: 2px;
    transform: none;
    transition: width 0.28s ease, background-color 0.2s ease;
  }
  .ob-nav__link:hover::before,
  .ob-nav__link:focus-visible::before { height: 2px; width: 100%; }
  .ob-nav__link[aria-current="page"]::before { height: 2px; width: 100%; }

  .ob-nav__num { font-size: 11px; width: 24px; flex: 0 0 auto; }
  .ob-nav__text {
    writing-mode: horizontal-tb;
    font-size: 17px;
    letter-spacing: 0.12em;
  }

  .ob-nav__foot {
    padding: 22px 0 0;
    border-top: 0;
    margin-top: 8px;
  }
  .ob-btn--rail {
    font-size: 14px;
    padding: 0.85em 1.2em;
    letter-spacing: 0.14em;
  }

  .ob-scrim {
    display: block;
    position: fixed;
    inset: 0;
    background: rgba(4, 9, 8, 0.64);
    -webkit-backdrop-filter: blur(2px);
    backdrop-filter: blur(2px);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
    z-index: 110;
  }
  .ob-head[data-open="true"] .ob-scrim { opacity: 1; visibility: visible; }

  .ob-progress {
    top: 64px;
    left: 0;
    right: 0;
    bottom: auto;
    width: auto;
    height: 2px;
  }
  .ob-progress__bar {
    height: 100%;
    width: calc(var(--p, 0) * 100%);
    background: linear-gradient(90deg, var(--cyan), var(--orange));
    transition: width 0.12s linear;
  }
}

@media (max-width: 720px) {
  .ob-grid--2,
  .ob-grid--3,
  .ob-grid--4 { grid-template-columns: minmax(0, 1fr); }

  .ob-foot__grid { grid-template-columns: minmax(0, 1fr); gap: 26px; }
  .ob-foot__col:last-child { grid-column: auto; }
  .ob-foot__top { align-items: flex-start; }
  .ob-foot__base { justify-content: flex-start; }
  .ob-section__head { align-items: flex-start; }
}

/* ============================================================
   16. 减少动态
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
  .ob-js [data-reveal] {
    opacity: 1;
    transform: none;
  }
  .ob-nav, .ob-scrim { transition: none !important; }
  .ob-progress__bar { transition: none !important; }
}