.page-about {
  --about-rail-w: 200px;
  background: var(--yb-bg);
  color: var(--yb-ink);
  overflow-x: hidden;
}

/* ---------- 面包屑 ---------- */
.page-about .yb-breadcrumb {
  padding-block: clamp(18px, 3vw, 28px) 0;
}

/* ---------- 首屏导语 ---------- */
.page-about .about-hero {
  position: relative;
  padding-block: clamp(10px, 2vw, 18px) clamp(34px, 6vw, 68px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 74%;
  background:
    radial-gradient(120% 90% at 10% 0%, rgba(53, 231, 192, 0.14), transparent 62%),
    linear-gradient(180deg, var(--yb-layer), rgba(12, 36, 30, 0));
  clip-path: polygon(0 0, 100% 0, 100% 76%, 0 100%);
  pointer-events: none;
  z-index: 0;
}

.page-about .about-hero > * {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__title {
  font-family: var(--yb-font-serif);
  font-weight: 700;
  font-size: clamp(32px, 7vw, 66px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  margin: 14px 0 clamp(22px, 4vw, 38px);
  max-width: 17ch;
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(16px, 3vw, 28px);
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 2fr) minmax(0, 1fr);
    gap: clamp(32px, 5vw, 68px);
    align-items: start;
  }
}

.page-about .about-hero__lede {
  margin: 0;
  max-width: 34ch;
}

.page-about .about-hero__note {
  margin: 0;
  color: var(--yb-muted);
  padding-left: 18px;
  border-left: 2px solid var(--yb-grid);
}

/* ---------- 首屏数据块 ---------- */
.page-about .about-metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(28px, 5vw, 48px) 0 0;
  background: var(--yb-grid);
  border-radius: var(--yb-radius);
  overflow: hidden;
}

@media (min-width: 760px) {
  .page-about .about-metrics {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .about-metrics__item {
  background: var(--yb-layer);
  padding: clamp(18px, 3vw, 28px);
  transition: background 0.2s ease;
}

.page-about .about-metrics__item:hover {
  background: var(--yb-bg);
}

.page-about .about-metrics__item dt {
  font-family: var(--yb-font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(28px, 5vw, 46px);
  line-height: 1;
  color: var(--yb-accent);
}

.page-about .about-metrics__item dd {
  margin: 10px 0 0;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--yb-muted);
}

/* ---------- 通栏主图 ---------- */
.page-about .about-cover {
  margin: 0 auto;
}

.page-about .about-cover .yb-media {
  border-radius: var(--yb-radius);
  overflow: hidden;
}

.page-about .about-cover__caption {
  margin-top: 12px;
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--yb-muted);
}

/* ---------- 主体两栏 ---------- */
.page-about .about-body {
  display: grid;
  gap: clamp(30px, 5vw, 48px);
  padding-block: clamp(46px, 8vw, 96px);
}

@media (min-width: 1024px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(36px, 5vw, 72px);
    align-items: start;
  }
}

/* ---------- 左侧赛季刻度 ---------- */
.page-about .about-rail {
  background: var(--yb-layer);
  border-radius: var(--yb-radius-sm);
  padding: 18px 20px;
}

.page-about .about-rail__label {
  margin: 0 0 12px;
  font-family: var(--yb-font-cond);
  text-transform: uppercase;
  letter-spacing: 0.14em;
  font-size: 12px;
  color: var(--yb-muted);
}

.page-about .about-rail__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 10px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  white-space: nowrap;
  padding: 8px 14px;
  border-radius: var(--yb-pill);
  border: 1px solid var(--yb-grid);
  color: var(--yb-muted);
  text-decoration: none;
  font-size: 14px;
  transition: color 0.18s ease, border-color 0.18s ease, background 0.18s ease;
}

.page-about .about-rail__link .yb-num {
  font-size: 12px;
  color: var(--yb-accent);
}

.page-about .about-rail__link:hover {
  color: var(--yb-ink);
  border-color: var(--yb-accent);
  background: rgba(53, 231, 192, 0.08);
}

.page-about .about-rail__link:focus-visible {
  outline: 2px solid var(--yb-signal);
  outline-offset: 2px;
}

@media (min-width: 1024px) {
  .page-about .about-rail {
    position: sticky;
    top: 108px;
    padding: 0 0 0 18px;
    background: transparent;
    border-radius: 0;
    border-left: 1px solid var(--yb-grid);
  }

  .page-about .about-rail__list {
    display: grid;
    gap: 6px;
    overflow: visible;
  }

  .page-about .about-rail__link {
    border-color: transparent;
    border-radius: var(--yb-pill);
    padding: 8px 12px;
  }
}

/* ---------- 章节骨架 ---------- */
.page-about .about-section {
  padding-block: clamp(28px, 5vw, 44px);
  border-top: 1px solid var(--yb-grid);
}

.page-about .about-section:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-section__head {
  margin-bottom: clamp(18px, 3vw, 30px);
}

.page-about .about-section .yb-h2 {
  margin: 10px 0 0;
  font-family: var(--yb-font-serif);
  font-weight: 600;
  font-size: clamp(24px, 4vw, 38px);
  line-height: 1.25;
  letter-spacing: -0.01em;
  max-width: 24ch;
}

.page-about .about-section p {
  max-width: 68ch;
}

.page-about .about-section .yb-text + .yb-text {
  margin-top: 14px;
}

.page-about .about-section a {
  color: var(--yb-accent);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 231, 192, 0.4);
}

.page-about .about-section a:hover {
  border-bottom-color: var(--yb-accent);
}

.page-about .about-section a:focus-visible {
  outline: 2px solid var(--yb-signal);
  outline-offset: 3px;
}

/* ---------- 演进：折线 + 规范示意图 ---------- */
.page-about .about-evolve {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
  margin-bottom: clamp(24px, 4vw, 40px);
}

@media (min-width: 900px) {
  .page-about .about-evolve {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    align-items: end;
  }
}

.page-about .about-chart {
  margin: 0;
}

.page-about .about-chart svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-chart__grid {
  stroke: var(--yb-grid);
  stroke-width: 1;
}

.page-about .about-chart__line {
  fill: none;
  stroke: var(--yb-accent);
  stroke-width: 2;
  stroke-linejoin: round;
}

.page-about .about-chart__node {
  fill: var(--yb-bg);
  stroke: var(--yb-accent);
  stroke-width: 2;
}

.page-about .about-chart__label {
  fill: var(--yb-muted);
  font-family: var(--yb-font-mono);
  font-size: 12px;
}

.page-about .about-chart__caption {
  margin-top: 10px;
  font-size: 13px;
  color: var(--yb-muted);
  letter-spacing: 0.02em;
}

.page-about .about-evolve__figure {
  margin: 0;
}

.page-about .about-evolve__figure .yb-media {
  border-radius: var(--yb-radius-sm);
  overflow: hidden;
}

.page-about .about-evolve__figure .yb-media__label {
  display: block;
  margin-top: 10px;
  font-size: 13px;
  color: var(--yb-muted);
}

/* ---------- 赛季条目 ---------- */
.page-about .about-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-step {
  background: var(--yb-layer);
  border: 1px solid transparent;
  border-radius: var(--yb-radius-sm);
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.page-about .about-step:hover {
  border-color: var(--yb-grid);
  transform: translateY(-4px);
}

.page-about .about-step[open] {
  border-color: var(--yb-accent);
}

.page-about .about-step summary {
  list-style: none;
  cursor: pointer;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 16px;
  padding: 16px 20px;
}

.page-about .about-step summary::-webkit-details-marker {
  display: none;
}

.page-about .about-step summary::after {
  content: "+";
  font-family: var(--yb-font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--yb-accent);
}

.page-about .about-step[open] summary::after {
  content: "–";
}

.page-about .about-step summary:focus-visible {
  outline: 2px solid var(--yb-signal);
  outline-offset: -2px;
}

.page-about .about-step__no {
  font-family: var(--yb-font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(20px, 3vw, 30px);
  line-height: 1;
  color: var(--yb-signal);
}

.page-about .about-step__name {
  font-family: var(--yb-font-serif);
  font-weight: 600;
  font-size: clamp(16px, 2.2vw, 20px);
  color: var(--yb-ink);
}

.page-about .about-step__body {
  padding: 0 20px 20px;
  border-top: 1px solid var(--yb-grid);
  margin-top: 2px;
  padding-top: 14px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--yb-muted);
}

.page-about .about-step__body p {
  margin: 0;
  max-width: 62ch;
}

/* ---------- 团队角色 ---------- */
.page-about .about-roles {
  display: grid;
  gap: 16px;
  margin-top: clamp(20px, 3vw, 32px);
}

@media (min-width: 760px) {
  .page-about .about-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-role {
  padding: clamp(20px, 3vw, 28px);
  border: 1px solid var(--yb-grid);
  border-radius: var(--yb-radius);
  background: linear-gradient(160deg, var(--yb-layer), rgba(6, 20, 16, 0.6));
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.page-about .about-role:hover {
  transform: translateY(-4px);
  border-color: var(--yb-accent);
}

.page-about .about-role__no {
  margin: 0;
  font-family: var(--yb-font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(34px, 6vw, 52px);
  line-height: 1;
  color: var(--yb-accent);
}

.page-about .about-role__title {
  margin: 12px 0 10px;
  font-family: var(--yb-font-cond);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 15px;
  color: var(--yb-ink);
}

.page-about .about-role__desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--yb-muted);
}

/* ---------- 复核流程 ---------- */
.page-about .about-flow {
  display: grid;
  gap: clamp(20px, 3vw, 36px);
}

@media (min-width: 860px) {
  .page-about .about-flow {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    align-items: start;
  }
}

.page-about .about-flow__figure {
  margin: 0;
}

.page-about .about-flow__figure .yb-media {
  border-radius: var(--yb-radius-sm);
  overflow: hidden;
}

.page-about .about-flow__figure .yb-media__label {
  display: block;
  margin-top: 10px;
  font-size: 13px;
  color: var(--yb-muted);
}

.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: clamp(18px, 3vw, 28px);
}

.page-about .about-timeline > li {
  padding-left: 20px;
  border-left: 2px solid var(--yb-grid);
  transition: border-color 0.2s ease;
}

.page-about .about-timeline > li:hover {
  border-color: var(--yb-accent);
}

.page-about .about-timeline__time {
  display: block;
  font-family: var(--yb-font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 15px;
  color: var(--yb-signal);
}

.page-about .about-timeline__title {
  margin: 8px 0 8px;
  font-family: var(--yb-font-cond);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 14px;
  color: var(--yb-ink);
}

.page-about .about-timeline__desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--yb-muted);
}

/* ---------- 跨赛季可比 ---------- */
.page-about .about-note {
  margin: clamp(20px, 3vw, 30px) 0;
}

.page-about .about-compare {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-compare li {
  padding: 14px 18px;
  border-radius: var(--yb-radius-sm);
  background: var(--yb-layer);
  font-size: 15px;
  line-height: 1.7;
  color: var(--yb-muted);
  max-width: 66ch;
}

.page-about .about-compare .yb-num {
  font-family: var(--yb-font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 20px;
  color: var(--yb-cool);
  margin-right: 4px;
}

/* ---------- 协作生态 ---------- */
.page-about .about-partners {
  display: grid;
  gap: 14px;
  margin-top: clamp(20px, 3vw, 30px);
}

@media (min-width: 760px) {
  .page-about .about-partners {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-partners__item {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  padding: clamp(18px, 3vw, 24px);
  border: 1px solid var(--yb-grid);
  border-radius: var(--yb-radius-sm);
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.page-about .about-partners__item:hover {
  border-color: var(--yb-accent);
  transform: translateY(-4px);
}

.page-about .about-partners__no {
  font-family: var(--yb-font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(26px, 4vw, 38px);
  line-height: 1;
  color: var(--yb-accent);
  flex: none;
}

.page-about .about-partners__item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--yb-muted);
}

/* ---------- 下一个赛季 ---------- */
.page-about .about-section--next {
  position: relative;
  overflow: hidden;
}

.page-about .about-section--next::before {
  content: "";
  position: absolute;
  inset: auto -10% -40% -10%;
  height: 70%;
  background: radial-gradient(60% 100% at 20% 100%, rgba(53, 231, 192, 0.13), transparent 70%);
  pointer-events: none;
}

.page-about .about-section--next > * {
  position: relative;
}

.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3vw, 32px);
}

.page-about .about-actions .yb-btn {
  text-decoration: none;
  border-bottom: 0;
}

/* ---------- 窄屏收口 ---------- */
@media (max-width: 560px) {
  .page-about .about-hero::before {
    height: 82%;
    clip-path: polygon(0 0, 100% 0, 100% 86%, 0 100%);
  }

  .page-about .about-hero__title {
    max-width: none;
  }

  .page-about .about-step summary {
    grid-template-columns: auto 1fr auto;
    gap: 12px;
    padding: 14px 16px;
  }

  .page-about .about-step__body {
    padding: 12px 16px 18px;
  }

  .page-about .about-actions .yb-btn {
    width: 100%;
    text-align: center;
  }
}