.page-about {
  --ab-space: clamp(18px, 3.6vw, 44px);
  background-color: var(--s828-bg);
  background-image:
    radial-gradient(1100px 560px at 88% -8%, rgba(61, 232, 210, 0.10), transparent 62%),
    radial-gradient(880px 480px at 3% 4%, rgba(255, 122, 85, 0.07), transparent 60%);
  color: var(--s828-ink);
}

.page-about .s828-crumbs {
  margin-top: 18px;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  padding-block: clamp(22px, 4vw, 44px) clamp(38px, 6.5vw, 80px);
}

.page-about .ab-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 48px);
}

.page-about .ab-hero__main .s828-h1 {
  margin: 12px 0 0;
  font-size: clamp(34px, 7.6vw, 78px);
  line-height: 1.04;
  letter-spacing: -0.03em;
  font-weight: 300;
  max-width: 15ch;
}

.page-about .ab-hero__main .s828-lede {
  margin: 20px 0 0;
  max-width: 58ch;
  font-size: clamp(15.5px, 1.7vw, 18px);
  line-height: 1.95;
  color: #C6D8E6;
}

.page-about .ab-hero__aside {
  align-self: end;
  padding: 16px clamp(14px, 2.4vw, 22px) 6px;
  border: 1px solid var(--s828-line);
  border-radius: var(--s828-radius-lg);
  background: var(--s828-glass);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
}

.page-about .ab-hero__aside-title {
  margin: 0;
  padding-bottom: 10px;
  font-family: var(--s828-font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.18em;
  color: var(--s828-muted);
}

/* ---------- 首屏章节索引 ---------- */
.page-about .ab-nav {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-nav__link {
  display: grid;
  grid-template-columns: 2.2rem minmax(0, 1fr);
  align-items: baseline;
  gap: 10px;
  min-height: 44px;
  padding: 12px 0;
  border-top: 1px solid var(--s828-line);
  color: var(--s828-muted);
  text-decoration: none;
  font-size: 15px;
  line-height: 1.4;
  transition: color 0.25s var(--s828-ease), padding-left 0.25s var(--s828-ease);
}

.page-about .ab-nav__link:hover,
.page-about .ab-nav__link:focus-visible {
  color: var(--s828-ink);
}

.page-about .ab-nav__link.is-active {
  color: var(--s828-cyan);
  padding-left: 6px;
}

.page-about .ab-nav__num {
  font-family: var(--s828-font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  opacity: 0.85;
}

/* ---------- 章节骨架 ---------- */
.page-about .ab-chapter {
  border-top: 1px solid var(--s828-line);
  padding-block: clamp(36px, 6vw, 80px);
}

.page-about .ab-chapter__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(14px, 2.6vw, 30px);
}

.page-about .ab-chapter__rail {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.page-about .ab-chapter__num {
  font-family: var(--s828-font-mono);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.16em;
  color: var(--s828-cyan);
}

.page-about .ab-chapter__label {
  margin: 0;
  font-family: var(--s828-font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--s828-muted);
}

.page-about .ab-chapter__body > .s828-h2 {
  margin: 0 0 16px;
  font-size: clamp(26px, 3.6vw, 42px);
  font-weight: 300;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.page-about .ab-prose-intro {
  margin: 0 0 6px;
  max-width: 60ch;
  font-size: clamp(15px, 1.5vw, 16.5px);
  line-height: 1.9;
  color: #C6D8E6;
}

.page-about .ab-prose-after {
  margin: clamp(20px, 3vw, 28px) 0 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.9;
  color: var(--s828-muted);
}

.page-about .ab-prose p {
  margin: 0 0 1.2em;
  max-width: 66ch;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.95;
  color: #CFE0EC;
}

.page-about .ab-prose p:last-child {
  margin-bottom: 0;
}

/* ---------- 引言块 ---------- */
.page-about .ab-quote {
  margin: clamp(22px, 3.5vw, 34px) 0 0;
  padding: clamp(18px, 3vw, 28px) clamp(18px, 3vw, 30px);
  border-left: 3px solid var(--s828-coral);
  border-radius: 0 var(--s828-radius) var(--s828-radius) 0;
  background: var(--s828-glass-soft);
  font-size: clamp(17px, 2.1vw, 21px);
  font-weight: 300;
  line-height: 1.9;
  letter-spacing: 0.01em;
  color: var(--s828-ink);
}

.page-about .ab-quote cite {
  display: block;
  margin-top: 12px;
  font-family: var(--s828-font-mono);
  font-style: normal;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--s828-muted);
}

/* ---------- 原则卡片 ---------- */
.page-about .ab-principles {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: clamp(20px, 3vw, 28px);
}

.page-about .ab-principle {
  padding: clamp(16px, 2.4vw, 24px);
  border: 1px solid var(--s828-line);
  border-radius: var(--s828-radius);
  background: var(--s828-glass);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
}

.page-about .ab-principle__num {
  display: inline-block;
  margin-bottom: 10px;
  font-family: var(--s828-font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--s828-coral);
}

.page-about .ab-principle__title {
  margin: 0 0 10px;
  font-size: clamp(17px, 2.2vw, 20px);
  font-weight: 600;
  line-height: 1.45;
  letter-spacing: -0.01em;
  color: var(--s828-ink);
}

.page-about .ab-principle__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: #C1D4E2;
}

.page-about .ab-more {
  margin-top: 14px;
  padding-top: 10px;
  border-top: 1px dashed var(--s828-line);
}

.page-about .ab-more > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  min-height: 44px;
  cursor: pointer;
  list-style: none;
  font-family: var(--s828-font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--s828-cyan);
}

.page-about .ab-more > summary::-webkit-details-marker {
  display: none;
}

.page-about .ab-more > summary::after {
  content: "+";
  font-size: 16px;
  line-height: 1;
  transition: transform 0.25s var(--s828-ease);
}

.page-about .ab-more[open] > summary::after {
  transform: rotate(45deg);
}

.page-about .ab-more p {
  margin: 4px 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--s828-muted);
}

/* ---------- 版本时间轴 ---------- */
.page-about .ab-timeline-figure {
  margin: clamp(20px, 3vw, 30px) 0 clamp(22px, 3.5vw, 34px);
}

.page-about .ab-timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 22px;
  border-left: 1px solid var(--s828-line);
  display: grid;
  gap: 24px;
}

.page-about .ab-timeline__item {
  position: relative;
}

.page-about .ab-timeline__item::before {
  content: "";
  position: absolute;
  left: -27px;
  top: 7px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--s828-cyan);
  box-shadow: 0 0 0 4px rgba(61, 232, 210, 0.16);
}

.page-about .ab-timeline__item--key::before {
  background: var(--s828-coral);
  box-shadow: 0 0 0 4px rgba(255, 122, 85, 0.18);
}

.page-about .ab-timeline__year {
  display: block;
  font-family: var(--s828-font-mono);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--s828-cyan);
}

.page-about .ab-timeline__item--key .ab-timeline__year {
  color: var(--s828-coral);
}

.page-about .ab-timeline__ver {
  display: inline-block;
  margin-top: 6px;
  padding: 2px 8px;
  border: 1px solid var(--s828-line);
  border-radius: 999px;
  font-family: var(--s828-font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--s828-muted);
}

.page-about .ab-timeline__desc {
  margin: 8px 0 0;
  max-width: 40ch;
  font-size: 14.5px;
  line-height: 1.85;
  color: #C1D4E2;
}

.page-about .ab-timeline__note {
  margin: clamp(20px, 3vw, 28px) 0 0;
  padding: 14px 16px;
  border-left: 2px solid var(--s828-amber);
  background: rgba(255, 194, 75, 0.07);
  border-radius: 0 var(--s828-radius) var(--s828-radius) 0;
  font-size: 14px;
  line-height: 1.85;
  color: #D8E4EE;
}

/* ---------- 团队 ---------- */
.page-about .ab-team-media {
  margin: clamp(20px, 3vw, 28px) 0 clamp(20px, 3vw, 28px);
}

.page-about .ab-teams {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .ab-team {
  padding: 18px;
  border-radius: var(--s828-radius);
  background: var(--s828-layer);
  border-left: 3px solid var(--s828-line);
}

.page-about .ab-team--cyan {
  border-left-color: var(--s828-cyan);
}

.page-about .ab-team--coral {
  border-left-color: var(--s828-coral);
}

.page-about .ab-team--amber {
  border-left-color: var(--s828-amber);
}

.page-about .ab-team--dim {
  border-left-color: var(--s828-cyan-dim);
}

.page-about .ab-team__name {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 0.01em;
  color: var(--s828-ink);
}

.page-about .ab-team__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: #C1D4E2;
}

/* ---------- 质量指标 ---------- */
.page-about .ab-metrics {
  margin: 0 0 clamp(22px, 3.5vw, 32px);
  border-top: 1px solid var(--s828-line);
}

.page-about .ab-metrics__row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 6px 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--s828-line);
}

.page-about .ab-metrics__label {
  flex: 1 1 12rem;
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--s828-muted);
}

.page-about .ab-metrics__value {
  flex: 0 0 auto;
  margin: 0;
  font-family: var(--s828-font-mono);
  font-size: clamp(16px, 2.2vw, 20px);
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--s828-cyan);
}

/* ---------- 页尾收束 ---------- */
.page-about .ab-final {
  padding-block: clamp(40px, 6vw, 78px) clamp(46px, 7vw, 92px);
  border-top: 1px solid var(--s828-line);
}

.page-about .ab-final__panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3.5vw, 40px);
  align-items: center;
  padding: clamp(20px, 3.5vw, 40px);
  border: 1px solid var(--s828-line);
  border-radius: var(--s828-radius-lg);
  background:
    linear-gradient(135deg, rgba(61, 232, 210, 0.10) 0%, rgba(255, 122, 85, 0.09) 82%),
    var(--s828-layer);
}

.page-about .ab-final__text > .s828-h2 {
  margin: 10px 0 14px;
  font-size: clamp(24px, 3.4vw, 38px);
  font-weight: 300;
  line-height: 1.22;
  letter-spacing: -0.02em;
}

.page-about .ab-final__desc {
  margin: 0;
  max-width: 56ch;
  font-size: clamp(14.5px, 1.5vw, 16px);
  line-height: 1.9;
  color: #C6D8E6;
}

.page-about .ab-final__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: clamp(18px, 2.6vw, 24px);
}

.page-about .ab-final__media {
  margin: 0;
}

/* ---------- 响应式 ---------- */
@media (min-width: 700px) {
  .page-about .ab-teams {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .ab-principles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }
}

@media (min-width: 860px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 1.7fr) minmax(0, 1fr);
    align-items: end;
  }

  .page-about .ab-chapter__grid {
    grid-template-columns: minmax(0, 196px) minmax(0, 1fr);
    gap: clamp(24px, 4vw, 56px);
  }

  .page-about .ab-chapter__rail {
    display: block;
    position: relative;
    align-self: start;
    padding-left: 20px;
  }

  .page-about .ab-chapter__rail::before {
    content: "";
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    border-radius: 2px;
    background: linear-gradient(180deg, var(--s828-cyan) 0%, rgba(61, 232, 210, 0) 92%);
    opacity: 0.7;
  }

  .page-about .ab-chapter__label {
    margin-top: 8px;
  }

  .page-about .ab-final__panel {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 0.75fr);
  }
}

@media (min-width: 1000px) {
  .page-about .ab-timeline {
    grid-auto-flow: column;
    grid-auto-columns: minmax(0, 1fr);
    align-items: start;
    gap: 16px;
    padding: 26px 0 0;
    border-left: 0;
    border-top: 1px solid var(--s828-line);
  }

  .page-about .ab-timeline__item::before {
    left: 0;
    top: -31px;
  }

  .page-about .ab-timeline__desc {
    max-width: none;
    font-size: 14px;
  }

  .page-about .ab-timeline__ver {
    font-size: 10.5px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-nav__link,
  .page-about .ab-more > summary::after {
    transition: none;
  }

  .page-about .ab-nav__link.is-active {
    padding-left: 0;
  }
}