.page-about {
  --ab-rail-w: 216px;
  --ab-gap: clamp(20px, 4vw, 40px);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  padding: clamp(20px, 4vw, 34px) 0 clamp(44px, 6vw, 78px);
  border-bottom: 2px solid var(--line);
  overflow: hidden;
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  top: -35%;
  right: -12%;
  width: 62vw;
  height: 175%;
  background: radial-gradient(ellipse at center, rgba(34, 225, 214, 0.11), transparent 66%);
  pointer-events: none;
}

.page-about .ab-hero .wrap {
  position: relative;
  z-index: 1;
}

.page-about .ab-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
  margin-top: clamp(22px, 3.5vw, 42px);
}

.page-about .ab-hero__title {
  margin: 12px 0 0;
  color: var(--white);
  font-weight: 900;
  letter-spacing: -0.035em;
  line-height: 1.1;
  max-width: 18em;
}

.page-about .ab-hero__lede {
  margin: 20px 0 0;
  max-width: 46em;
  color: var(--text);
  line-height: 1.8;
}

.page-about .ab-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

/* 首屏数据块 */
.page-about .ab-hero__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px;
  background: var(--line);
  border: 2px solid var(--line);
  align-self: start;
}

.page-about .ab-stat {
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  gap: 6px;
  min-height: 106px;
  padding: 16px 16px 18px;
  background: var(--bg-2);
}

.page-about .ab-stat:nth-child(2),
.page-about .ab-stat:nth-child(3) {
  background: var(--bg-3);
}

.page-about .ab-stat__num {
  font-family: var(--font-mono);
  font-size: clamp(28px, 5vw, 44px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--white);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-stat__plus {
  font-size: 0.55em;
  color: var(--cyan);
  margin-left: 2px;
}

.page-about .ab-stat__label {
  font-size: 13px;
  line-height: 1.5;
  color: var(--text);
}

/* ---------- 章节标题 ---------- */
.page-about .ab-sec-head {
  margin-bottom: clamp(24px, 3.5vw, 40px);
}

.page-about .ab-sec-head h2 {
  margin: 12px 0 0;
  color: var(--white);
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.15;
}

.page-about .ab-sec-head__sub {
  margin: 14px 0 0;
  max-width: 58ch;
  color: var(--text);
  line-height: 1.75;
}

/* ---------- 时间轴 ---------- */
.page-about .ab-timeline {
  padding: clamp(46px, 7vw, 96px) 0;
  background: var(--bg);
  border-bottom: 2px solid var(--line);
}

.page-about .ab-timeline__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

.page-about .ab-rail {
  align-self: start;
  border: 2px solid var(--line);
  background: var(--bg-2);
  padding: 16px;
}

.page-about .ab-rail .eyebrow {
  margin: 0;
}

.page-about .ab-rail__list {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: flex;
  gap: 10px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .ab-rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 8px 12px;
  border: 2px solid var(--line);
  background: var(--bg-3);
  text-decoration: none;
  white-space: nowrap;
  transition: border-color 180ms ease, background-color 180ms ease;
}

.page-about .ab-rail__link:hover,
.page-about .ab-rail__link:focus-visible {
  border-color: var(--cyan);
  background: rgba(34, 225, 214, 0.09);
}

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

.page-about .ab-rail__yr {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--cyan);
}

.page-about .ab-rail__tag {
  font-size: 12px;
  color: var(--text);
}

/* 内容流 */
.page-about .ab-stream__media {
  margin: 0 0 clamp(28px, 4vw, 48px);
}

.page-about .media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .ab-node {
  position: relative;
  padding: 0 0 40px clamp(18px, 3vw, 34px);
  border-left: 2px solid var(--line);
}

.page-about .ab-node:last-child {
  padding-bottom: 0;
}

.page-about .ab-node::before {
  content: "";
  position: absolute;
  left: -8px;
  top: 8px;
  width: 14px;
  height: 14px;
  background: var(--bg);
  border: 2px solid var(--cyan);
}

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

.page-about .ab-node:target .ab-node__yr {
  color: var(--cyan);
}

.page-about .ab-node--now {
  border-left-color: var(--gold);
}

.page-about .ab-node--now::before {
  border-color: var(--gold);
  background: var(--gold);
}

.page-about .ab-node__yr {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(32px, 5.5vw, 54px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--white);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-node__badge {
  display: inline-block;
  margin: 12px 0 0;
  padding: 3px 9px;
  border: 2px solid var(--cyan);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--cyan);
}

.page-about .ab-node__badge--now {
  border-color: var(--gold);
  color: var(--gold);
}

.page-about .ab-node__title {
  margin: 16px 0 0;
  font-size: clamp(19px, 2.2vw, 24px);
  font-weight: 700;
  letter-spacing: -0.015em;
  line-height: 1.35;
  color: var(--white);
}

.page-about .ab-node__body {
  margin: 12px 0 0;
  max-width: 60ch;
  color: var(--text);
  line-height: 1.8;
}

/* ---------- 团队分工 ---------- */
.page-about .ab-team {
  padding: clamp(46px, 7vw, 96px) 0;
  background: var(--bg-2);
  border-bottom: 2px solid var(--line);
}

.page-about .ab-roles {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
}

.page-about .ab-role {
  position: relative;
  padding: 26px 22px 24px;
  background: var(--bg-3);
  border: 2px solid var(--line);
  border-left: 4px solid var(--cyan);
  transition: transform 200ms ease, border-color 200ms ease, box-shadow 200ms ease;
}

.page-about .ab-role:nth-child(2) {
  border-left-color: var(--gold);
}

.page-about .ab-role:nth-child(3) {
  border-left-color: var(--rose);
}

.page-about .ab-role:hover,
.page-about .ab-role:focus-visible {
  transform: translateY(-6px);
  border-color: var(--cyan);
  box-shadow: 8px 8px 0 0 rgba(34, 225, 214, 0.18);
  outline: none;
}

.page-about .ab-role:focus-visible {
  box-shadow: 8px 8px 0 0 rgba(34, 225, 214, 0.18), 0 0 0 2px var(--cyan);
}

.page-about .ab-role:hover .ab-role__note,
.page-about .ab-role:focus-visible .ab-role__note {
  border-top-color: var(--cyan);
  color: var(--white);
}

.page-about .ab-role__idx {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .ab-role:nth-child(2) .ab-role__idx {
  color: var(--gold);
}

.page-about .ab-role:nth-child(3) .ab-role__idx {
  color: var(--rose);
}

.page-about .ab-role__title {
  margin: 0;
  font-size: clamp(20px, 2.2vw, 25px);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--white);
}

.page-about .ab-role__desc {
  margin: 14px 0 0;
  color: var(--text);
  line-height: 1.8;
}

.page-about .ab-role__note {
  margin: 18px 0 0;
  padding-top: 14px;
  border-top: 2px solid var(--line);
  font-size: 13px;
  line-height: 1.7;
  color: var(--text);
  transition: border-color 200ms ease, color 200ms ease;
}

/* ---------- 归档流程 ---------- */
.page-about .ab-flow {
  padding: clamp(46px, 7vw, 96px) 0;
  background: var(--bg);
  border-bottom: 2px solid var(--line);
}

.page-about .ab-flow__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
  align-items: start;
}

.page-about .ab-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: abstep;
}

.page-about .ab-step {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 16px;
  align-items: start;
  padding: 22px 0;
  border-top: 2px solid var(--line);
  transition: background-color 180ms ease;
}

.page-about .ab-step:last-child {
  border-bottom: 2px solid var(--line);
}

.page-about .ab-step:hover,
.page-about .ab-step:focus-within {
  background: rgba(34, 225, 214, 0.05);
}

.page-about .ab-step__no {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: 0.02em;
  color: var(--cyan);
  padding-top: 2px;
}

.page-about .ab-step__title {
  margin: 0;
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--white);
  line-height: 1.4;
}

.page-about .ab-step__body p {
  margin: 8px 0 0;
  color: var(--text);
  line-height: 1.78;
}

.page-about .ab-flow__aside {
  border: 2px solid var(--line);
  background: var(--bg-2);
  padding: 16px;
}

.page-about .ab-flow__aside .media {
  margin: 0;
}

.page-about .ab-flow__note {
  margin: 16px 0 0;
  padding-top: 16px;
  border-top: 2px solid var(--line);
  font-size: 14px;
  line-height: 1.75;
  color: var(--text);
}

/* ---------- 数据源 ---------- */
.page-about .ab-sources {
  padding: clamp(46px, 7vw, 96px) 0;
  background: var(--bg-2);
  border-bottom: 2px solid var(--line);
}

.page-about .ab-src-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2px;
  background: var(--line);
  border: 2px solid var(--line);
}

.page-about .ab-src {
  background: var(--bg-3);
  padding: 26px 22px 28px;
  border-left: 4px solid var(--cyan);
  transition: background-color 200ms ease;
}

.page-about .ab-src--gold {
  border-left-color: var(--gold);
}

.page-about .ab-src--rose {
  border-left-color: var(--rose);
}

.page-about .ab-src:hover {
  background: var(--bg-2);
}

.page-about .ab-src__k {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .ab-src--gold .ab-src__k {
  color: var(--gold);
}

.page-about .ab-src--rose .ab-src__k {
  color: var(--rose);
}

.page-about .ab-src__t {
  margin: 0;
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.012em;
  color: var(--white);
  line-height: 1.4;
}

.page-about .ab-src__d {
  margin: 12px 0 0;
  color: var(--text);
  line-height: 1.78;
  max-width: 46ch;
}

.page-about .ab-src__d a,
.page-about .ab-sources__foot a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 2px solid rgba(34, 225, 214, 0.4);
}

.page-about .ab-src__d a:hover,
.page-about .ab-src__d a:focus-visible,
.page-about .ab-sources__foot a:hover,
.page-about .ab-sources__foot a:focus-visible {
  border-bottom-color: var(--cyan);
  outline: none;
}

.page-about .ab-sources__foot {
  margin: 24px 0 0;
  color: var(--text);
  line-height: 1.8;
  max-width: 68ch;
}

/* ---------- 本地服务 ---------- */
.page-about .ab-local {
  padding: clamp(46px, 7vw, 96px) 0;
  background: var(--bg);
  border-bottom: 2px solid var(--line);
}

.page-about .ab-local__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
  align-items: start;
}

.page-about .ab-local__intro {
  margin: 16px 0 0;
  max-width: 52ch;
  color: var(--text);
  line-height: 1.8;
}

.page-about .ab-local__list {
  margin: 26px 0 28px;
  padding: 0;
  border-top: 2px solid var(--line);
}

.page-about .ab-local__row {
  display: grid;
  grid-template-columns: minmax(0, 96px) minmax(0, 1fr);
  gap: 14px;
  padding: 14px 0;
  border-bottom: 2px solid var(--line);
}

.page-about .ab-local__row dt {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--cyan);
  padding-top: 3px;
}

.page-about .ab-local__row dd {
  margin: 0;
  color: var(--white);
  line-height: 1.6;
  word-break: break-word;
}

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

/* ---------- 结尾 ---------- */
.page-about .ab-cta {
  padding: clamp(46px, 7vw, 92px) 0 clamp(56px, 8vw, 104px);
  background: var(--bg-2);
}

.page-about .ab-cta__box {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  padding: clamp(26px, 4vw, 46px);
  background: var(--bg-3);
  border: 2px solid var(--line);
  border-top: 4px solid var(--cyan);
  box-shadow: 12px 12px 0 0 rgba(34, 225, 214, 0.12);
}

.page-about .ab-cta__text h2 {
  margin: 12px 0 0;
  color: var(--white);
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.15;
}

.page-about .ab-cta__text p {
  margin: 16px 0 0;
  max-width: 62ch;
  color: var(--text);
  line-height: 1.8;
}

.page-about .ab-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-content: start;
}

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-about .ab-roles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

@media (min-width: 900px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 52px;
    align-items: start;
  }

  .page-about .ab-timeline__grid {
    grid-template-columns: var(--ab-rail-w) minmax(0, 1fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .ab-rail {
    position: sticky;
    top: 96px;
    padding: 18px 0 18px 18px;
  }

  .page-about .ab-rail__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    border-left: 2px solid var(--line);
    margin-top: 16px;
  }

  .page-about .ab-rail__link {
    display: grid;
    grid-template-columns: 54px minmax(0, 1fr);
    gap: 8px;
    align-items: baseline;
    margin-left: -2px;
    border: 0;
    border-left: 2px solid transparent;
    background: transparent;
    padding: 12px 12px 12px 14px;
    white-space: normal;
  }

  .page-about .ab-rail__link:hover,
  .page-about .ab-rail__link:focus-visible {
    border-left-color: var(--cyan);
    background: linear-gradient(90deg, rgba(34, 225, 214, 0.12), transparent 78%);
  }

  .page-about .ab-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 22px;
  }

  .page-about .ab-roles .ab-role:nth-child(2) {
    margin-top: 26px;
  }

  .page-about .ab-roles .ab-role:nth-child(3) {
    margin-top: 52px;
  }

  .page-about .ab-flow__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 44px;
  }

  .page-about .ab-flow__aside {
    position: sticky;
    top: 96px;
  }

  .page-about .ab-src-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .ab-src:nth-child(2),
  .page-about .ab-src:nth-child(4) {
    background: var(--bg-2);
  }

  .page-about .ab-local__grid {
    grid-template-columns: minmax(0, 6fr) minmax(0, 6fr);
    gap: 48px;
  }

  .page-about .ab-cta__box {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: end;
    gap: 36px;
  }
}

@media (min-width: 1200px) {
  .page-about .ab-hero__grid {
    gap: 64px;
  }

  .page-about .ab-local__grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-role,
  .page-about .ab-role__note,
  .page-about .ab-src,
  .page-about .ab-step {
    transition: none;
  }

  .page-about .ab-role:hover,
  .page-about .ab-role:focus-visible {
    transform: none;
  }
}