/* ============================================================
   忆博战队 · 中文站 共享样式 /assets/site.css
   暗夜墨蓝基底 + 框景刻度 + 霓虹青单一强调色
   ============================================================ */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 110px;
}

body {
  margin: 0;
  background-color: var(--yb-ink);
  color: var(--yb-text);
  font-family: var(--yb-font-sans);
  font-size: 16px;
  line-height: 1.85;
  font-weight: 400;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img, svg, video, canvas { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
input, textarea, select { font: inherit; color: inherit; }
table { border-collapse: collapse; width: 100%; }
hr { border: 0; }

/* ---------- 2. Tokens ---------- */
:root {
  --yb-ink: #060A14;
  --yb-panel: #0D1526;
  --yb-steel: #16213D;
  --yb-line: #2B3A63;
  --yb-muted: #8A93AD;
  --yb-body: #C7CFE3;
  --yb-text: #E8ECF6;
  --yb-cyan: #35F0D0;
  --yb-purple: #7A5CFF;
  --yb-orange: #FF8A2B;
  --yb-alert: #FF3D6E;

  --yb-font-sans: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", "Heiti SC", sans-serif;
  --yb-font-mono: "JetBrains Mono", "SFMono-Regular", "Cascadia Mono", Consolas, "Courier New", monospace;

  --yb-radius-lg: 32px;
  --yb-radius: 24px;
  --yb-radius-sm: 16px;
  --yb-pill: 999px;

  --yb-container: 1240px;
  --yb-gutter: clamp(20px, 5vw, 64px);
  --yb-header-h: 84px;

  --yb-shadow-card: 0 18px 50px rgba(0, 0, 0, 0.45);
  --yb-glow-cyan: 0 0 14px rgba(53, 240, 208, 0.75);
}

/* ---------- 3. 基础排版 ---------- */
.yb-container {
  width: 100%;
  max-width: var(--yb-container);
  margin-inline: auto;
  padding-inline: var(--yb-gutter);
}

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

.yb-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.7em;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--yb-muted);
}
.yb-eyebrow::before {
  content: "";
  width: 26px;
  height: 1px;
  background: var(--yb-cyan);
  box-shadow: var(--yb-glow-cyan);
}

.yb-display {
  font-size: clamp(2.6rem, 9vw, 8.25rem);
  font-weight: 900;
  line-height: 0.9;
  letter-spacing: -0.03em;
  color: var(--yb-text);
}
.yb-display--glow {
  -webkit-text-stroke: 1px rgba(53, 240, 208, 0.35);
  text-shadow: 1px 0 0 rgba(122, 92, 255, 0.55), -1px 0 0 rgba(53, 240, 208, 0.4);
}
.yb-display--sm { font-size: clamp(2rem, 5.2vw, 4.4rem); }

.yb-lede {
  max-width: 30em;
  font-size: clamp(15px, 1.6vw, 19px);
  line-height: 1.9;
  color: #B9C2D8;
}

.yb-prose {
  max-width: 34em;
  font-size: 17px;
  line-height: 1.85;
  color: var(--yb-body);
}
.yb-prose h2,
.yb-prose h3 {
  margin-block: 1.6em 0.6em;
  color: var(--yb-text);
  font-weight: 800;
  line-height: 1.3;
  letter-spacing: -0.01em;
}
.yb-prose h2 { font-size: clamp(22px, 2.4vw, 30px); }
.yb-prose h3 { font-size: clamp(18px, 1.8vw, 22px); }
.yb-prose p + p { margin-top: 1.1em; }
.yb-prose strong { color: var(--yb-text); font-weight: 700; }
.yb-prose a {
  color: var(--yb-cyan);
  border-bottom: 1px solid rgba(53, 240, 208, 0.4);
}

/* ---------- 4. 通用按钮 ---------- */
.yb-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  padding: 0.72em 1.5em;
  border-radius: var(--yb-pill);
  border: 1px solid transparent;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1.2;
  white-space: nowrap;
  transition: transform 0.35s ease, background-color 0.35s ease, border-color 0.35s ease, box-shadow 0.35s ease, color 0.35s ease;
}

.yb-btn--action {
  background: var(--yb-orange);
  color: #150A02;
  box-shadow: 0 8px 26px rgba(255, 138, 43, 0.28);
}
.yb-btn--action:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 34px rgba(255, 138, 43, 0.4);
}

.yb-btn--cyan {
  background: var(--yb-cyan);
  color: #03110E;
}
.yb-btn--cyan:hover { transform: translateY(-2px); box-shadow: 0 12px 30px rgba(53, 240, 208, 0.32); }

.yb-btn--ghost {
  background: rgba(22, 33, 61, 0.55);
  border-color: var(--yb-line);
  color: var(--yb-text);
}
.yb-btn--ghost:hover {
  border-color: var(--yb-cyan);
  color: var(--yb-cyan);
  transform: translateY(-2px);
}

.yb-btn--line {
  background: transparent;
  border-color: rgba(53, 240, 208, 0.5);
  color: var(--yb-cyan);
}
.yb-btn--line:hover { background: rgba(53, 240, 208, 0.1); }

/* ---------- 5. 头部 ---------- */
.yb-skip {
  position: absolute;
  left: 50%;
  top: 8px;
  transform: translate(-50%, -160%);
  z-index: 120;
  padding: 10px 20px;
  border-radius: var(--yb-pill);
  background: var(--yb-cyan);
  color: #03110E;
  font-size: 14px;
  font-weight: 700;
  transition: transform 0.25s ease;
}
.yb-skip:focus { transform: translate(-50%, 0); }

.yb-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 60;
  background: linear-gradient(180deg, rgba(6, 10, 20, 0.86) 0%, rgba(6, 10, 20, 0) 100%);
  border-bottom: 1px solid transparent;
  transition: background-color 0.4s ease, border-color 0.4s ease, backdrop-filter 0.4s ease;
}
.yb-header[data-scrolled="true"] {
  background: rgba(6, 10, 20, 0.94);
  border-bottom-color: var(--yb-line);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

.yb-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  height: var(--yb-header-h);
  transition: height 0.35s ease;
}
.yb-header[data-scrolled="true"] .yb-header__inner { height: 64px; }

.yb-brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
}
.yb-brand__mark {
  display: block;
  width: 24px;
  height: 4px;
  border-radius: 2px;
  background: var(--yb-cyan);
  box-shadow: var(--yb-glow-cyan);
}
.yb-brand__text { display: flex; flex-direction: column; gap: 2px; line-height: 1.1; }
.yb-brand__name {
  font-size: 19px;
  font-weight: 900;
  letter-spacing: 0.06em;
  color: var(--yb-text);
}
.yb-brand__sub {
  font-size: 10px;
  letter-spacing: 0.28em;
  color: var(--yb-muted);
  transition: opacity 0.3s ease, max-height 0.3s ease;
}
.yb-header[data-scrolled="true"] .yb-brand__sub { opacity: 0; max-height: 0; overflow: hidden; }

/* 导航：移动端为右侧胶囊抽屉 */
.yb-nav {
  position: fixed;
  top: 0;
  right: 0;
  width: min(340px, 86vw);
  height: 100dvh;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 24px;
  padding: calc(var(--yb-header-h) + 12px) 28px 40px;
  background: linear-gradient(200deg, rgba(13, 21, 38, 0.99), rgba(6, 10, 20, 0.99));
  border-left: 1px solid var(--yb-line);
  border-radius: 28px 0 0 28px;
  box-shadow: -24px 0 60px rgba(0, 0, 0, 0.5);
  transform: translateX(106%);
  visibility: hidden;
  z-index: 80;
  transition: transform 0.45s cubic-bezier(0.22, 0.9, 0.24, 1), visibility 0.45s ease;
}
.yb-nav[data-open="true"] { transform: translateX(0); visibility: visible; }

.yb-nav__list { display: flex; flex-direction: column; }
.yb-nav__item { border-bottom: 1px solid rgba(43, 58, 99, 0.55); }
.yb-nav__link {
  display: block;
  padding: 15px 2px;
  font-size: 19px;
  font-weight: 700;
  letter-spacing: 0.03em;
  color: var(--yb-text);
  transition: color 0.3s ease, padding-left 0.3s ease;
}
.yb-nav__link:hover { color: var(--yb-cyan); padding-left: 10px; }
.yb-nav__link[aria-current="page"] {
  color: var(--yb-cyan);
  box-shadow: inset 3px 0 0 var(--yb-cyan);
  padding-left: 14px;
}
.yb-nav__foot { display: flex; }
.yb-nav__cta { width: 100%; }

.yb-nav-scrim {
  position: fixed;
  inset: 0;
  z-index: 70;
  background: rgba(3, 6, 14, 0.68);
  backdrop-filter: blur(3px);
  -webkit-backdrop-filter: blur(3px);
}
.yb-nav-scrim[hidden] { display: none; }

.yb-header__actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
}

.yb-status-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 14px;
  border: 1px solid var(--yb-line);
  border-radius: var(--yb-pill);
  background: rgba(13, 21, 38, 0.7);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--yb-muted);
  white-space: nowrap;
}
.yb-status-pill__dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--yb-cyan);
  box-shadow: var(--yb-glow-cyan);
  animation: yb-pulse 3s ease-in-out infinite;
}
@keyframes yb-pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.35; }
}

.yb-nav-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  border-radius: var(--yb-pill);
  border: 1px solid var(--yb-line);
  background: rgba(13, 21, 38, 0.85);
  transition: border-color 0.3s ease, background-color 0.3s ease;
}
.yb-nav-toggle:hover { border-color: var(--yb-cyan); }
.yb-nav-toggle__bars {
  display: flex;
  flex-direction: column;
  gap: 5px;
  width: 20px;
}
.yb-nav-toggle__bars span {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: var(--yb-cyan);
  transition: transform 0.32s ease, opacity 0.32s ease;
}
.yb-nav-toggle[aria-expanded="true"] .yb-nav-toggle__bars span:first-child { transform: translateY(3.5px) rotate(45deg); }
.yb-nav-toggle[aria-expanded="true"] .yb-nav-toggle__bars span:last-child { transform: translateY(-3.5px) rotate(-45deg); }

/* ---------- 6. 页脚 ---------- */
.yb-footer {
  position: relative;
  margin-top: clamp(64px, 10vw, 140px);
  background: linear-gradient(180deg, rgba(13, 21, 38, 0.9), var(--yb-ink) 78%);
  border-top: 1px solid var(--yb-line);
  border-radius: var(--yb-radius-lg) var(--yb-radius-lg) 0 0;
  overflow: hidden;
}
.yb-footer::before {
  content: "";
  position: absolute;
  inset: 0 auto auto 0;
  width: 60%;
  height: 320px;
  background: radial-gradient(70% 100% at 0% 0%, rgba(122, 92, 255, 0.18), transparent 70%);
  pointer-events: none;
}
.yb-footer__inner {
  position: relative;
  z-index: 1;
  padding-block: clamp(48px, 7vw, 88px) clamp(24px, 3vw, 36px);
}

.yb-footer__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 4vw, 48px);
}

.yb-footer__brand { display: flex; flex-direction: column; gap: 16px; }
.yb-footer__desc {
  max-width: 26em;
  font-size: 15px;
  line-height: 1.8;
  color: var(--yb-body);
}
.yb-footer__status {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--yb-muted);
}
.yb-footer__status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--yb-cyan);
  box-shadow: var(--yb-glow-cyan);
}

.yb-footer__col { display: flex; flex-direction: column; gap: 14px; }
.yb-footer__heading {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--yb-muted);
}
.yb-footer__list { display: flex; flex-direction: column; gap: 10px; }
.yb-footer__link {
  display: inline-block;
  font-size: 15px;
  color: var(--yb-body);
  border-bottom: 1px solid transparent;
  transition: color 0.3s ease, border-color 0.3s ease, transform 0.3s ease;
}
.yb-footer__link:hover {
  color: var(--yb-cyan);
  border-bottom-color: rgba(53, 240, 208, 0.6);
  transform: translateX(4px);
}

.yb-footer__facts { display: flex; flex-direction: column; gap: 12px; }
.yb-footer__fact { display: flex; flex-direction: column; gap: 3px; }
.yb-footer__fact-label {
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--yb-muted);
}
.yb-footer__fact-value {
  font-size: 14px;
  line-height: 1.7;
  color: var(--yb-text);
  word-break: break-word;
}
.yb-footer__note {
  font-size: 13px;
  line-height: 1.7;
  color: var(--yb-muted);
}
.yb-footer__icp {
  font-size: 13px;
  color: var(--yb-muted);
}

.yb-footer__legal {
  margin-top: clamp(32px, 5vw, 56px);
  padding-top: 20px;
  border-top: 1px solid var(--yb-line);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 10px 24px;
}
.yb-footer__copyright { font-size: 13px; color: var(--yb-text); }
.yb-footer__legal-note { font-size: 12px; color: var(--yb-muted); }

/* 赛程刻度带 */
.yb-ticker {
  position: relative;
  overflow: hidden;
  border-top: 1px solid var(--yb-line);
  background: rgba(6, 10, 20, 0.8);
  padding-block: 12px;
}
.yb-ticker__track {
  display: flex;
  align-items: center;
  gap: 40px;
  width: max-content;
  animation: yb-ticker-scroll 46s linear infinite;
}
.yb-ticker__item {
  font-family: var(--yb-font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--yb-muted);
  white-space: nowrap;
}
.yb-ticker__item::after {
  content: "◆";
  margin-left: 40px;
  color: rgba(53, 240, 208, 0.5);
  font-size: 8px;
  vertical-align: middle;
}
@keyframes yb-ticker-scroll {
  from { transform: translate3d(0, 0, 0); }
  to { transform: translate3d(-50%, 0, 0); }
}

/* ---------- 7. 滚动进度与返回顶部 ---------- */
.yb-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  z-index: 90;
  pointer-events: none;
}
.yb-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: left center;
  background: linear-gradient(90deg, var(--yb-cyan), var(--yb-purple));
  box-shadow: 0 0 12px rgba(53, 240, 208, 0.5);
}

.yb-backtop {
  position: fixed;
  right: clamp(16px, 3vw, 34px);
  bottom: clamp(16px, 3vw, 34px);
  z-index: 85;
  width: 50px;
  height: 50px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--yb-pill);
  border: 1px solid var(--yb-line);
  background: rgba(13, 21, 38, 0.92);
  color: var(--yb-cyan);
  font-size: 18px;
  opacity: 0;
  transform: translateY(14px);
  pointer-events: none;
  transition: opacity 0.35s ease, transform 0.35s ease, border-color 0.35s ease;
}
.yb-backtop[data-visible="true"] {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}
.yb-backtop:hover { border-color: var(--yb-cyan); box-shadow: 0 0 22px rgba(53, 240, 208, 0.22); }

/* ---------- 8. 章节与版式容器 ---------- */
.yb-section {
  position: relative;
  padding-block: clamp(56px, 8vw, 120px);
}
.yb-section--tight { padding-block: clamp(32px, 5vw, 64px); }
.yb-section--band {
  background: linear-gradient(180deg, rgba(22, 33, 61, 0.72), rgba(13, 21, 38, 0.32));
  border-block: 1px solid var(--yb-line);
}
.yb-section__head {
  display: flex;
  flex-direction: column;
  gap: 18px;
  margin-bottom: clamp(28px, 4vw, 52px);
}

.yb-divider {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--yb-line) 12%, var(--yb-line) 88%, transparent);
}
.yb-divider--accent { background: linear-gradient(90deg, var(--yb-cyan), transparent 70%); }

.yb-slice {
  position: relative;
  background: linear-gradient(120deg, rgba(122, 92, 255, 0.16), rgba(53, 240, 208, 0.08));
  clip-path: polygon(0 3%, 100% 0, 100% 97%, 0 100%);
  padding: clamp(28px, 5vw, 72px);
  border-radius: var(--yb-radius-lg);
}

/* ---------- 9. 框景刻度容器 ---------- */
.yb-frame {
  position: relative;
  border: 1px solid var(--yb-line);
  border-radius: var(--yb-radius-lg);
  padding: clamp(26px, 4.5vw, 64px);
  overflow: hidden;
  background:
    radial-gradient(120% 140% at 10% 0%, rgba(122, 92, 255, 0.16), transparent 58%),
    linear-gradient(160deg, rgba(13, 21, 38, 0.94), rgba(6, 10, 20, 0.92));
}
.yb-frame::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 14px;
  background-image: repeating-linear-gradient(90deg, var(--yb-line) 0 1px, transparent 1px 22px);
  opacity: 0.9;
  pointer-events: none;
}
.yb-frame--tight { padding: clamp(20px, 3vw, 36px); }
.yb-frame__corner {
  position: absolute;
  width: 22px;
  height: 22px;
  border: 1px solid var(--yb-cyan);
  pointer-events: none;
}
.yb-frame__corner--tl { top: 16px; left: 16px; border-right: 0; border-bottom: 0; border-radius: 10px 0 0 0; }
.yb-frame__corner--tr { top: 16px; right: 16px; border-left: 0; border-bottom: 0; border-radius: 0 10px 0 0; }
.yb-frame__corner--bl { bottom: 16px; left: 16px; border-right: 0; border-top: 0; border-radius: 0 0 0 10px; }
.yb-frame__corner--br { bottom: 16px; right: 16px; border-left: 0; border-top: 0; border-radius: 0 0 10px 0; }

/* ---------- 10. 栅格与卡片 ---------- */
.yb-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(16px, 2.4vw, 28px);
}
.yb-grid--2 { grid-template-columns: 1fr; }
.yb-grid--3 { grid-template-columns: 1fr; }

.yb-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: clamp(20px, 2.6vw, 32px);
  border: 1px solid var(--yb-line);
  border-radius: var(--yb-radius);
  background: linear-gradient(160deg, rgba(22, 33, 61, 0.85), rgba(13, 21, 38, 0.92));
  transition: transform 0.4s ease, border-color 0.4s ease, box-shadow 0.4s ease;
}
.yb-card:hover {
  transform: scale(1.02);
  border-color: rgba(53, 240, 208, 0.6);
  box-shadow: var(--yb-shadow-card);
}
.yb-card__title {
  font-size: clamp(18px, 2vw, 22px);
  font-weight: 800;
  line-height: 1.4;
  letter-spacing: -0.01em;
  color: var(--yb-text);
}
.yb-card__body { font-size: 15px; line-height: 1.8; color: var(--yb-body); }
.yb-card__meta {
  margin-top: auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-family: var(--yb-font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--yb-muted);
}

/* ---------- 11. 徽章 / 胶囊标签 / 数据块 ---------- */
.yb-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.45em;
  padding: 0.32em 0.9em;
  border: 1px solid currentColor;
  border-radius: var(--yb-pill);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  line-height: 1.6;
}
.yb-badge--cyan { color: var(--yb-cyan); background: rgba(53, 240, 208, 0.1); }
.yb-badge--purple { color: var(--yb-purple); background: rgba(122, 92, 255, 0.14); }
.yb-badge--orange { color: var(--yb-orange); background: rgba(255, 138, 43, 0.12); }
.yb-badge--alert { color: var(--yb-alert); background: rgba(255, 61, 110, 0.12); }

.yb-chips { display: flex; flex-wrap: wrap; gap: 10px; }
.yb-tab {
  padding: 0.55em 1.25em;
  border: 1px solid var(--yb-line);
  border-radius: var(--yb-pill);
  background: rgba(13, 21, 38, 0.62);
  color: var(--yb-muted);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.04em;
  transition: color 0.3s ease, background-color 0.3s ease, border-color 0.3s ease;
}
.yb-tab:hover { color: var(--yb-text); border-color: var(--yb-cyan); }
.yb-tab[aria-selected="true"] {
  background: var(--yb-cyan);
  border-color: var(--yb-cyan);
  color: #03110E;
}
.yb-panel[hidden] { display: none; }
.yb-panel { display: block; }

.yb-stat { display: flex; flex-direction: column; gap: 6px; }
.yb-stat__value {
  font-family: var(--yb-font-mono);
  font-size: clamp(28px, 4vw, 46px);
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--yb-cyan);
}
.yb-stat__label {
  font-size: 12px;
  letter-spacing: 0.24em;
  color: var(--yb-muted);
}

/* ---------- 12. 图片容器基础规则 ---------- */
.yb-media {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--yb-line);
  border-radius: var(--yb-radius);
  background: linear-gradient(140deg, var(--yb-steel), var(--yb-ink));
}
.yb-media > img,
.yb-media > video {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.yb-media::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(6, 10, 20, 0) 42%, rgba(6, 10, 20, 0.78) 100%);
  pointer-events: none;
}
.yb-media--wide { aspect-ratio: 16 / 9; }
.yb-media--bleed { aspect-ratio: 21 / 9; }
.yb-media--tall { aspect-ratio: 3 / 4; }
.yb-media--square { aspect-ratio: 1 / 1; }
.yb-media__tag {
  position: absolute;
  left: 16px;
  bottom: 16px;
  z-index: 2;
  font-family: var(--yb-font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--yb-cyan);
}
.yb-media__placeholder {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  letter-spacing: 0.28em;
  color: rgba(138, 147, 173, 0.7);
  background-image:
    repeating-linear-gradient(0deg, rgba(43, 58, 99, 0.5) 0 1px, transparent 1px 60px),
    repeating-linear-gradient(90deg, rgba(43, 58, 99, 0.5) 0 1px, transparent 1px 60px);
}

/* ---------- 13. 面包屑与章节索引 ---------- */
.yb-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6em;
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--yb-muted);
}
.yb-breadcrumb__item { display: flex; align-items: center; gap: 0.6em; }
.yb-breadcrumb__item + .yb-breadcrumb__item::before {
  content: "/";
  color: var(--yb-line);
}
.yb-breadcrumb__link { color: var(--yb-muted); transition: color 0.3s ease; }
.yb-breadcrumb__link:hover { color: var(--yb-cyan); }
.yb-breadcrumb__item[aria-current="page"] { color: var(--yb-text); }

.yb-index { display: none; }
.yb-index__list { display: flex; flex-direction: column; gap: 16px; }
.yb-index__link {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--yb-muted);
  transition: color 0.3s ease;
}
.yb-index__link::before {
  content: "";
  width: 18px;
  height: 1px;
  background: currentColor;
  transition: width 0.3s ease;
}
.yb-index__link:hover { color: var(--yb-text); }
.yb-index__link[aria-current="true"] { color: var(--yb-cyan); }
.yb-index__link[aria-current="true"]::before { width: 34px; box-shadow: var(--yb-glow-cyan); }

/* ---------- 14. 入场动效 ---------- */
.yb-js [data-reveal] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s cubic-bezier(0.2, 0.7, 0.3, 1), transform 0.6s cubic-bezier(0.2, 0.7, 0.3, 1);
  transition-delay: var(--yb-delay, 0ms);
}
.yb-js [data-reveal].is-visible { opacity: 1; transform: none; }

/* ---------- 15. 焦点可见 ---------- */
:focus-visible {
  outline: 2px solid var(--yb-cyan);
  outline-offset: 3px;
  border-radius: 6px;
}

/* ---------- 16. 响应式 ---------- */
@media (min-width: 640px) {
  .yb-grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .yb-grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .yb-footer__grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 899px) {
  .yb-status-pill { display: none; }
}

@media (max-width: 639px) {
  .yb-header__cta { display: none; }
  .yb-brand__sub { display: none; }
  .yb-media--wide { aspect-ratio: 4 / 3; }
}

@media (min-width: 1024px) {
  .yb-nav {
    position: static;
    height: auto;
    width: auto;
    flex-direction: row;
    align-items: center;
    justify-content: flex-end;
    flex: 1 1 auto;
    gap: 0;
    padding: 0;
    background: none;
    border: 0;
    border-radius: 0;
    box-shadow: none;
    transform: none;
    visibility: visible;
    transition: none;
  }
  .yb-nav__list {
    flex-direction: row;
    align-items: center;
    gap: clamp(12px, 2vw, 30px);
  }
  .yb-nav__item { border-bottom: 0; }
  .yb-nav__link {
    position: relative;
    padding: 6px 2px;
    font-size: 15px;
    font-weight: 600;
    letter-spacing: 0.04em;
    color: var(--yb-body);
  }
  .yb-nav__link:hover { color: var(--yb-cyan); padding-left: 2px; }
  .yb-nav__link::after {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    bottom: 0;
    height: 2px;
    border-radius: 2px;
    background: var(--yb-cyan);
    transform: scaleX(0);
    transform-origin: left center;
    transition: transform 0.32s ease;
  }
  .yb-nav__link:hover::after,
  .yb-nav__link[aria-current="page"]::after { transform: scaleX(1); }
  .yb-nav__link[aria-current="page"] {
    color: var(--yb-cyan);
    padding-left: 2px;
    box-shadow: none;
  }
  .yb-nav__foot { display: none; }
  .yb-nav-scrim { display: none !important; }
  .yb-nav-toggle { display: none; }

  .yb-footer__grid { grid-template-columns: 1.6fr 1fr 1.3fr 1fr; }
}

@media (min-width: 1200px) {
  .yb-grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .yb-index {
    display: block;
    position: fixed;
    left: clamp(12px, calc((100vw - var(--yb-container)) / 2 - 110px), 96px);
    top: 50%;
    transform: translateY(-50%);
    z-index: 40;
  }
}

@media (min-width: 1200px) and (max-width: 1500px) {
  .yb-index { left: 16px; }
}

@media (min-width: 1024px) {
  .yb-grid--stagger > *:nth-child(even) { margin-top: clamp(20px, 4vw, 56px); }
}

/* ---------- 17. 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;
    transition-delay: 0ms !important;
  }
  .yb-js [data-reveal] { opacity: 1 !important; transform: none !important; }
  .yb-ticker__track { animation: none !important; }
  .yb-status-pill__dot { animation: none !important; }
  .yb-card:hover { transform: none; }
}