/* ==========================================================================
   优博赛场 · 共享站点套件 /assets/site.css
   夜场直播氛围 + 数据仪表盘质感 + 粗野主义细节
   ========================================================================== */

/* ---------- 1. 变量 ---------- */
:root {
  --yb-navy: #0B1B33;
  --yb-navy-2: #14294A;
  --yb-navy-3: #1C3660;
  --yb-cyan: #16E0C8;
  --yb-orange: #FF5A2B;
  --yb-yellow: #FFC93C;
  --yb-paper: #F4F6F8;
  --yb-graphite: #2A3547;
  --yb-mist: #D7F4F0;
  --yb-red: #E5484D;

  --yb-fg: #F4F6F8;
  --yb-muted: rgba(244, 246, 248, 0.68);
  --yb-line: rgba(244, 246, 248, 0.16);
  --yb-surface: #14294A;
  --yb-shadow-card: 8px 8px 0 0 rgba(22, 224, 200, 0.85);

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

  --yb-radius: 2px;
  --yb-max: 1240px;
  --yb-header-h: 76px;
  --yb-gutter: clamp(18px, 4vw, 56px);
  --yb-ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--yb-header-h) + 28px);
}

body {
  margin: 0;
  background: var(--yb-navy);
  color: var(--yb-fg);
  font-family: var(--yb-font-sans);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd { margin: 0; }

ul, ol { margin: 0; padding: 0; list-style: none; }

a { color: inherit; text-decoration: none; }

button { font: inherit; color: inherit; }

table { border-collapse: collapse; width: 100%; }

hr { border: 0; }

:where(a, button, [tabindex], input, select, textarea):focus-visible {
  outline: 3px solid var(--yb-cyan);
  outline-offset: 3px;
  border-radius: var(--yb-radius);
}

/* ---------- 3. 通用容器与网格 ---------- */
.yb-shell {
  width: 100%;
  max-width: var(--yb-max);
  margin-inline: auto;
  padding-inline: var(--yb-gutter);
}

.yb-shell--wide { max-width: 1440px; }

.yb-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(20px, 3vw, 44px);
}

.yb-col-4 { grid-column: span 4; }
.yb-col-5 { grid-column: span 5; }
.yb-col-6 { grid-column: span 6; }
.yb-col-7 { grid-column: span 7; }
.yb-col-8 { grid-column: span 8; }
.yb-col-12 { grid-column: span 12; }

.yb-cluster {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}

.yb-stack { display: flex; flex-direction: column; gap: 14px; }

.yb-flow > * + * { margin-top: 14px; }

.yb-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;
}

/* ---------- 4. 分区与色环境翻转 ---------- */
.yb-section {
  position: relative;
  padding-block: clamp(56px, 8vw, 120px);
}

.yb-section--dark {
  background: var(--yb-navy);
  color: var(--yb-fg);
}

.yb-section--slate {
  background: var(--yb-navy-2);
  color: var(--yb-fg);
}

.yb-section--paper,
.yb-section--mist {
  --yb-fg: #2A3547;
  --yb-muted: rgba(42, 53, 71, 0.72);
  --yb-line: rgba(42, 53, 71, 0.16);
  --yb-surface: #FFFFFF;
  --yb-shadow-card: 8px 8px 0 0 var(--yb-navy);
  color: var(--yb-fg);
}

.yb-section--paper { background: var(--yb-paper); }
.yb-section--mist { background: var(--yb-mist); }

/* ---------- 5. 字体系统 ---------- */
.yb-kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 18px;
  font-family: var(--yb-font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--yb-cyan);
}

.yb-kicker::before {
  content: "";
  width: 26px;
  height: 2px;
  background: var(--yb-cyan);
  flex: 0 0 auto;
}

.yb-h1 {
  margin-bottom: 24px;
  font-size: clamp(44px, 9vw, 128px);
  font-weight: 900;
  letter-spacing: -0.03em;
  line-height: 0.96;
}

.yb-h2 {
  margin-bottom: 20px;
  font-size: clamp(28px, 4vw, 56px);
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.08;
}

.yb-h3 {
  margin-bottom: 14px;
  font-size: clamp(20px, 2.2vw, 24px);
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.3;
}

.yb-lede {
  margin-bottom: 26px;
  max-width: 52ch;
  font-size: clamp(17px, 1.6vw, 21px);
  font-weight: 500;
  line-height: 1.7;
  color: var(--yb-muted);
}

.yb-body {
  margin-bottom: 18px;
  max-width: 68ch;
  font-size: 16px;
  line-height: 1.75;
  color: var(--yb-muted);
}

.yb-num,
.yb-mono {
  font-family: var(--yb-font-mono);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum" 1, "lnum" 1;
  letter-spacing: -0.01em;
}

.yb-text-cyan { color: var(--yb-cyan); }
.yb-text-yellow { color: var(--yb-yellow); }
.yb-text-orange { color: var(--yb-orange); }

.yb-mt-lg { margin-top: clamp(28px, 4vw, 56px); }

/* ---------- 6. 按钮 ---------- */
.yb-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 20px;
  border: 2px solid currentColor;
  border-radius: var(--yb-radius);
  background: transparent;
  color: var(--yb-cyan);
  font-family: var(--yb-font-sans);
  font-size: 15px;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: 0.02em;
  cursor: pointer;
  text-align: center;
  transition: background-color 0.2s var(--yb-ease), color 0.2s var(--yb-ease),
    border-color 0.2s var(--yb-ease), box-shadow 0.2s var(--yb-ease),
    transform 0.2s var(--yb-ease);
}

.yb-btn:hover {
  background: var(--yb-cyan);
  border-color: var(--yb-cyan);
  color: var(--yb-navy);
}

.yb-btn--cyan {
  background: var(--yb-cyan);
  border-color: var(--yb-cyan);
  color: var(--yb-navy);
}

.yb-btn--cyan:hover {
  background: var(--yb-paper);
  border-color: var(--yb-paper);
  color: var(--yb-navy);
  box-shadow: 4px 4px 0 0 var(--yb-cyan);
  transform: translateY(-2px);
}

.yb-btn--orange {
  background: var(--yb-orange);
  border-color: var(--yb-orange);
  color: #FFFFFF;
}

.yb-btn--orange:hover {
  background: var(--yb-paper);
  border-color: var(--yb-paper);
  color: var(--yb-navy);
  box-shadow: 4px 4px 0 0 var(--yb-orange);
  transform: translateY(-2px);
}

.yb-btn--ghost {
  background: transparent;
  border-color: rgba(244, 246, 248, 0.45);
  color: var(--yb-paper);
}

.yb-btn--ghost:hover {
  background: var(--yb-paper);
  border-color: var(--yb-paper);
  color: var(--yb-navy);
}

/* ---------- 7. 头部 ---------- */
.yb-header {
  position: fixed;
  top: 0;
  right: 0;
  left: 0;
  z-index: 60;
  background: linear-gradient(
    180deg,
    rgba(11, 27, 51, 0.94) 0%,
    rgba(11, 27, 51, 0.6) 62%,
    rgba(11, 27, 51, 0) 100%
  );
  border-bottom: 2px solid transparent;
  transition: background-color 0.24s var(--yb-ease),
    border-color 0.24s var(--yb-ease), box-shadow 0.24s var(--yb-ease);
}

.yb-header.is-scrolled {
  background: var(--yb-navy);
  border-bottom-color: var(--yb-cyan);
  box-shadow: 0 18px 34px -26px rgba(0, 0, 0, 0.95);
}

.yb-header__inner {
  display: flex;
  align-items: center;
  gap: clamp(14px, 3vw, 42px);
  max-width: var(--yb-max);
  min-height: var(--yb-header-h);
  margin-inline: auto;
  padding-inline: var(--yb-gutter);
}

.yb-skip {
  position: absolute;
  top: -120px;
  left: 12px;
  z-index: 90;
  padding: 10px 16px;
  background: var(--yb-cyan);
  color: var(--yb-navy);
  font-size: 14px;
  font-weight: 700;
  border-radius: var(--yb-radius);
  transition: top 0.2s var(--yb-ease);
}

.yb-skip:focus {
  top: 12px;
}

/* 品牌 */
.yb-brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  padding: 10px 0;
}

.yb-brand__mark {
  position: relative;
  width: 14px;
  height: 14px;
  flex: 0 0 auto;
  background: var(--yb-cyan);
  border-radius: 50%;
  box-shadow: 0 0 0 4px rgba(22, 224, 200, 0.16),
    0 0 18px rgba(22, 224, 200, 0.7);
}

.yb-brand__mark::after {
  content: "";
  position: absolute;
  top: -5px;
  right: -7px;
  width: 6px;
  height: 6px;
  background: var(--yb-yellow);
}

.yb-brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.yb-brand__name {
  font-size: 19px;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--yb-paper);
}

.yb-brand__line {
  font-family: var(--yb-font-mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--yb-cyan);
}

/* 导航 */
.yb-nav {
  margin-left: auto;
}

.yb-nav__list {
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.6vw, 26px);
}

.yb-nav__link {
  position: relative;
  display: inline-block;
  padding: 8px 2px;
  font-size: 15px;
  font-weight: 600;
  color: rgba(244, 246, 248, 0.78);
  transition: color 0.18s var(--yb-ease);
}

.yb-nav__link::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: 0;
  left: 0;
  height: 3px;
  background: var(--yb-cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.22s var(--yb-ease);
}

.yb-nav__link:hover,
.yb-nav__link:focus-visible {
  color: var(--yb-paper);
}

.yb-nav__link:hover::after,
.yb-nav__link:focus-visible::after {
  transform: scaleX(1);
}

.yb-nav__link[aria-current="page"] {
  color: var(--yb-cyan);
}

.yb-nav__link[aria-current="page"]::after {
  transform: scaleX(1);
}

.yb-nav__cta { display: none; }

/* 头部操作区 */
.yb-header__actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
}

.yb-header__cta { padding: 10px 18px; font-size: 14px; }

.yb-nav__toggle {
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  padding: 9px 12px;
  background: transparent;
  border: 2px solid rgba(244, 246, 248, 0.42);
  border-radius: var(--yb-radius);
  color: var(--yb-paper);
  cursor: pointer;
  transition: border-color 0.2s var(--yb-ease),
    background-color 0.2s var(--yb-ease);
}

.yb-nav__toggle:hover {
  border-color: var(--yb-cyan);
  background: rgba(22, 224, 200, 0.12);
}

.yb-nav__toggle-bar {
  display: block;
  width: 18px;
  height: 2px;
  background: currentColor;
}

.yb-nav__toggle-label {
  font-family: var(--yb-font-mono);
  font-size: 10px;
  letter-spacing: 0.16em;
}

/* 滚动进度 */
.yb-progress {
  position: absolute;
  right: 0;
  bottom: 0;
  left: 0;
  height: 3px;
  background: rgba(22, 224, 200, 0.12);
  pointer-events: none;
}

.yb-progress__bar {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--yb-cyan), var(--yb-orange));
  transition: width 0.1s linear;
}

/* ---------- 8. 页脚 ---------- */
.yb-footer {
  position: relative;
  background: var(--yb-navy-2);
  color: var(--yb-fg);
  border-top: 2px solid var(--yb-line);
}

.yb-footer__inner {
  max-width: var(--yb-max);
  margin-inline: auto;
  padding: clamp(40px, 6vw, 76px) var(--yb-gutter) clamp(22px, 3vw, 34px);
}

.yb-footer__hero {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 18px;
  padding-bottom: clamp(22px, 3vw, 34px);
  border-bottom: 2px solid var(--yb-line);
}

.yb-footer__eyebrow {
  margin-bottom: 10px;
  font-family: var(--yb-font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--yb-cyan);
}

.yb-footer__claim {
  font-size: clamp(22px, 2.6vw, 34px);
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.24;
  color: var(--yb-paper);
}

.yb-footer__grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: clamp(22px, 3.4vw, 48px);
  padding-block: clamp(28px, 4vw, 48px);
}

.yb-footer__col--brand { min-width: 0; }

.yb-footer__brand {
  margin-bottom: 6px;
  font-size: 20px;
  font-weight: 900;
  letter-spacing: -0.01em;
  color: var(--yb-paper);
}

.yb-footer__brand-line {
  margin-bottom: 14px;
  font-family: var(--yb-font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--yb-cyan);
}

.yb-footer__note {
  max-width: 34ch;
  font-size: 14px;
  line-height: 1.7;
  color: rgba(244, 246, 248, 0.6);
}

.yb-footer__col-title {
  margin-bottom: 16px;
  font-family: var(--yb-font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--yb-yellow);
}

.yb-footer__list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.yb-footer__list a {
  position: relative;
  display: inline-block;
  font-size: 15px;
  color: rgba(244, 246, 248, 0.72);
  transition: color 0.18s var(--yb-ease), transform 0.18s var(--yb-ease);
}

.yb-footer__list a::before {
  content: "";
  position: absolute;
  top: 0.72em;
  left: -14px;
  width: 8px;
  height: 2px;
  background: var(--yb-cyan);
  opacity: 0;
  transition: opacity 0.18s var(--yb-ease);
}

.yb-footer__list a:hover,
.yb-footer__list a:focus-visible {
  color: var(--yb-cyan);
  transform: translateX(6px);
}

.yb-footer__list a:hover::before,
.yb-footer__list a:focus-visible::before {
  opacity: 1;
}

.yb-footer__contact {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 8px 26px;
  padding-block: clamp(22px, 3vw, 34px);
  border-top: 2px solid var(--yb-line);
  border-bottom: 2px solid var(--yb-line);
}

.yb-footer__contact-label {
  grid-row: 1 / -1;
  font-family: var(--yb-font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--yb-yellow);
}

.yb-footer__contact-row {
  font-family: var(--yb-font-mono);
  font-size: 14px;
  letter-spacing: 0.01em;
  line-height: 1.7;
  color: rgba(244, 246, 248, 0.74);
  word-break: break-word;
}

.yb-footer__base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 28px;
  padding-top: clamp(18px, 2.4vw, 26px);
}

.yb-footer__legal,
.yb-footer__year {
  font-family: var(--yb-font-mono);
  font-size: 13px;
  letter-spacing: 0.01em;
  color: rgba(244, 246, 248, 0.52);
}

.yb-footer__rule {
  height: 12px;
  background: repeating-linear-gradient(
    90deg,
    var(--yb-cyan) 0 2px,
    transparent 2px 18px
  );
  opacity: 0.34;
}

.yb-backtop {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  background: transparent;
  border: 2px solid var(--yb-cyan);
  border-radius: var(--yb-radius);
  color: var(--yb-cyan);
  font-family: var(--yb-font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.22s var(--yb-ease), visibility 0.22s var(--yb-ease),
    background-color 0.2s var(--yb-ease), color 0.2s var(--yb-ease);
}

.yb-backtop[data-visible="true"] {
  opacity: 1;
  visibility: visible;
}

.yb-backtop:hover {
  background: var(--yb-cyan);
  color: var(--yb-navy);
}

/* ---------- 9. 内容组件 ---------- */
.yb-card {
  position: relative;
  display: block;
  padding: clamp(20px, 2.4vw, 30px);
  background: var(--yb-surface);
  border: 2px solid var(--yb-line);
  border-radius: var(--yb-radius);
  color: var(--yb-fg);
  transition: transform 0.22s var(--yb-ease), box-shadow 0.22s var(--yb-ease),
    border-color 0.22s var(--yb-ease);
}

.yb-card:hover,
.yb-card:focus-within {
  transform: translateY(-4px);
  border-color: var(--yb-cyan);
  box-shadow: var(--yb-shadow-card);
}

.yb-card--float { margin-top: clamp(-32px, -3vw, -14px); }

.yb-card__meta {
  margin-bottom: 12px;
  font-family: var(--yb-font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--yb-cyan);
}

.yb-card__title {
  margin-bottom: 10px;
  font-size: 20px;
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.32;
}

.yb-card__text {
  font-size: 15px;
  line-height: 1.7;
  color: var(--yb-muted);
}

.yb-scorecard {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 14px;
  padding: 16px 22px;
  background: var(--yb-surface);
  border: 2px solid var(--yb-line);
  border-left: 6px solid var(--yb-orange);
  border-radius: var(--yb-radius);
}

.yb-scorecard__team {
  font-size: 15px;
  font-weight: 700;
  line-height: 1.4;
}

.yb-scorecard__team:last-of-type { text-align: right; }

.yb-scorecard__score {
  font-family: var(--yb-font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(28px, 4vw, 44px);
  font-weight: 600;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--yb-yellow);
}

.yb-scorecard__meta {
  grid-column: 1 / -1;
  font-family: var(--yb-font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--yb-muted);
}

.yb-figure {
  position: relative;
  display: block;
  margin: 0;
  border: 2px solid var(--yb-line);
  border-radius: var(--yb-radius);
  background: linear-gradient(135deg, var(--yb-navy-2), var(--yb-navy) 55%, #0A1830);
  overflow: hidden;
}

.yb-figure::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: linear-gradient(90deg, rgba(22, 224, 200, 0.14) 1px, transparent 1px),
    linear-gradient(0deg, rgba(22, 224, 200, 0.14) 1px, transparent 1px);
  background-size: 42px 42px;
  pointer-events: none;
}

.yb-figure__img {
  position: relative;
  z-index: 1;
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  filter: saturate(1.05) contrast(1.06);
}

.yb-figure--portrait .yb-figure__img { aspect-ratio: 4 / 5; }
.yb-figure--square .yb-figure__img { aspect-ratio: 1 / 1; }

.yb-figure__caption {
  position: relative;
  z-index: 2;
  padding: 10px 14px;
  border-top: 2px solid var(--yb-line);
  font-family: var(--yb-font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--yb-muted);
}

.yb-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border: 1px solid var(--yb-cyan);
  border-radius: var(--yb-radius);
  font-family: var(--yb-font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--yb-cyan);
}

.yb-tag--orange { border-color: var(--yb-orange); color: var(--yb-orange); }
.yb-tag--yellow { border-color: var(--yb-yellow); color: var(--yb-yellow); }

.yb-aside {
  padding: 20px 22px;
  border-left: 4px solid var(--yb-yellow);
  background: rgba(255, 201, 60, 0.09);
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--yb-muted);
}

.yb-index {
  border-top: 2px solid var(--yb-line);
}

.yb-index__item {
  border-bottom: 2px solid var(--yb-line);
}

.yb-index__link {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 14px 2px;
  transition: color 0.18s var(--yb-ease), padding-left 0.18s var(--yb-ease);
}

.yb-index__link:hover,
.yb-index__link:focus-visible {
  color: var(--yb-cyan);
  padding-left: 12px;
}

.yb-index__no {
  flex: 0 0 auto;
  min-width: 34px;
  font-family: var(--yb-font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--yb-yellow);
}

.yb-index__text {
  font-size: 16px;
  font-weight: 600;
}

.yb-timeline {
  position: relative;
  padding-left: 2px;
}

.yb-timeline::before {
  content: "";
  position: absolute;
  top: 8px;
  bottom: 8px;
  left: 9px;
  width: 2px;
  background: linear-gradient(180deg, var(--yb-cyan), rgba(22, 224, 200, 0.08));
}

.yb-timeline__item {
  position: relative;
  padding: 0 0 30px 42px;
}

.yb-timeline__item:last-child { padding-bottom: 0; }

.yb-timeline__node {
  position: absolute;
  top: 5px;
  left: 0;
  width: 20px;
  height: 20px;
  border: 3px solid var(--yb-line);
  border-radius: 50%;
  background: var(--yb-navy);
  transition: border-color 0.24s var(--yb-ease),
    background-color 0.24s var(--yb-ease), box-shadow 0.24s var(--yb-ease);
}

.yb-timeline__item.is-active .yb-timeline__node {
  border-color: var(--yb-cyan);
  background: var(--yb-cyan);
  box-shadow: 0 0 0 5px rgba(22, 224, 200, 0.16);
}

.yb-rule {
  height: 2px;
  margin-block: clamp(28px, 4vw, 52px);
  background: var(--yb-line);
}

.yb-rule--dashed {
  height: 0;
  background: none;
  border-top: 2px dashed var(--yb-line);
}

.yb-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 26px;
  font-family: var(--yb-font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--yb-muted);
}

.yb-breadcrumb li {
  display: flex;
  align-items: center;
  gap: 8px;
}

.yb-breadcrumb li + li::before {
  content: "/";
  color: var(--yb-cyan);
}

.yb-breadcrumb a {
  color: var(--yb-muted);
  transition: color 0.18s var(--yb-ease);
}

.yb-breadcrumb a:hover { color: var(--yb-cyan); }

.yb-prose {
  max-width: 68ch;
}

.yb-prose p {
  margin-bottom: 18px;
  line-height: 1.8;
}

.yb-prose a {
  color: var(--yb-cyan);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
  transition: background-color 0.18s var(--yb-ease), color 0.18s var(--yb-ease);
}

.yb-prose a:hover {
  background: var(--yb-cyan);
  color: var(--yb-navy);
  text-decoration: none;
}

.yb-prose ul,
.yb-prose ol {
  margin-bottom: 18px;
  padding-left: 1.25em;
  list-style: disc;
}

.yb-prose ol { list-style: decimal; }

.yb-prose li {
  margin-bottom: 8px;
  line-height: 1.75;
}

/* ---------- 10. 显现 ---------- */
.yb-reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.5s var(--yb-ease), transform 0.5s var(--yb-ease);
}

.yb-reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* ---------- 11. 响应式 ---------- */
@media (max-width: 1100px) {
  .yb-footer__grid { grid-template-columns: 1fr 1fr; }
  .yb-footer__col--brand { grid-column: 1 / -1; }
}

@media (max-width: 900px) {
  .yb-header__actions { margin-left: auto; }

  .yb-nav {
    position: absolute;
    top: 100%;
    right: 0;
    left: 0;
    display: none;
    margin: 0;
    padding: 10px var(--yb-gutter) 24px;
    background: var(--yb-navy-2);
    border-top: 2px solid var(--yb-line);
    border-bottom: 2px solid var(--yb-cyan);
    max-height: calc(100vh - var(--yb-header-h));
    overflow-y: auto;
    box-shadow: 0 30px 60px -30px rgba(0, 0, 0, 0.92);
  }

  .yb-nav[data-open="true"] { display: block; }

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

  .yb-nav__item {
    border-bottom: 1px solid var(--yb-line);
  }

  .yb-nav__link {
    display: block;
    padding: 16px 2px;
    font-size: 17px;
  }

  .yb-nav__link::after { height: 0; }

  .yb-nav__link[aria-current="page"] {
    padding-left: 14px;
    border-left: 4px solid var(--yb-cyan);
  }

  .yb-nav__cta {
    display: inline-flex;
    width: 100%;
    margin-top: 20px;
  }

  .yb-nav__toggle { display: inline-flex; }

  .yb-col-4,
  .yb-col-5,
  .yb-col-6,
  .yb-col-7,
  .yb-col-8 { grid-column: span 12; }

  .yb-card--float { margin-top: 0; }
}

@media (max-width: 640px) {
  .yb-header__cta { display: none; }

  .yb-brand__line { display: none; }

  .yb-footer__contact {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .yb-footer__contact-label { grid-row: auto; }

  .yb-footer__base { flex-direction: column; align-items: flex-start; }

  .yb-scorecard {
    grid-template-columns: 1fr;
    gap: 10px;
    text-align: left;
  }

  .yb-scorecard__team:last-of-type { text-align: left; }
}

@media (max-width: 560px) {
  .yb-footer__grid { grid-template-columns: 1fr; }
}

/* ---------- 12. 动效降级 ---------- */
@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;
  }

  .yb-reveal {
    opacity: 1;
    transform: none;
  }

  .yb-backtop { transition: none; }
}