.page-about {
  --ab-rule: 2px solid var(--line);
  --ab-pad: clamp(18px, 3vw, 28px);
  background: var(--ink-900);
  color: var(--warm);
}

.page-about .breadcrumb {
  padding: 14px 0 0;
  font-size: 13px;
}

.page-about a:focus-visible,
.page-about summary:focus-visible,
.page-about button:focus-visible {
  outline: 3px solid var(--cyan);
  outline-offset: 3px;
}

.page-about img {
  max-width: 100%;
  height: auto;
}

.page-about .eyebrow {
  color: var(--cyan);
  letter-spacing: .16em;
  text-transform: uppercase;
}

.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--font-display);
  color: var(--warm);
}

.page-about h2 {
  font-size: clamp(24px, 4.4vw, 40px);
  font-weight: 900;
  letter-spacing: -.015em;
  line-height: 1.16;
  margin: 8px 0 0;
}

.page-about h3 {
  font-size: clamp(19px, 2.7vw, 25px);
  font-weight: 800;
  line-height: 1.36;
  letter-spacing: -.01em;
  margin: 8px 0 0;
}

.page-about p {
  line-height: 1.8;
  margin: 10px 0 0;
}

.page-about .lede {
  color: var(--mist);
  font-size: clamp(15px, 2vw, 17px);
  line-height: 1.8;
  max-width: 36em;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  padding: clamp(18px, 3vw, 32px) 0 clamp(36px, 6vw, 72px);
}

.page-about .ab-hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 4vw, 52px);
  align-items: start;
}

.page-about h1 {
  font-size: clamp(34px, 8.4vw, 66px);
  font-weight: 900;
  line-height: 1.04;
  letter-spacing: -.03em;
  margin: 14px 0 0;
}

.page-about .ab-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3vw, 30px);
}

.page-about .ab-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0;
  margin: clamp(26px, 4vw, 38px) 0 0;
  border-top: 2px solid var(--line-strong);
}

.page-about .ab-stat {
  padding: 14px 10px 0 0;
  border-right: 1px solid var(--line);
}

.page-about .ab-stat:last-child {
  border-right: 0;
}

.page-about .ab-stat dt {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .04em;
  color: var(--mist-dim);
  line-height: 1.5;
}

.page-about .ab-stat dd {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-size: clamp(19px, 3.4vw, 30px);
  font-weight: 700;
  color: var(--warm);
  letter-spacing: -.01em;
}

.page-about .ab-hero-visual {
  border: 2px solid var(--line-strong);
  background: var(--ink-800);
  box-shadow: 9px 9px 0 var(--signal);
  padding: 10px;
}

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

.page-about .ab-hero-caption {
  margin: 10px 0 0;
  font-size: 11.5px;
  letter-spacing: .05em;
  color: var(--mist-dim);
  line-height: 1.6;
}

/* ---------- 通用章节 ---------- */
.page-about .ab-sect {
  padding: clamp(36px, 6vw, 84px) 0;
}

.page-about .ab-head {
  display: grid;
  gap: 6px;
  max-width: 46em;
  margin-bottom: clamp(24px, 4vw, 44px);
}

/* ---------- 时间线 ---------- */
.page-about .ab-timeline {
  border-top: 2px solid var(--line);
}

.page-about .ab-timeline-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(18px, 3vw, 34px);
}

.page-about .ab-axis-title {
  font-size: 11.5px;
  letter-spacing: .16em;
  color: var(--mist-dim);
  margin: 0 0 10px;
}

.page-about .ab-axis-list {
  display: flex;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0 0 10px;
  overflow-x: auto;
  scroll-snap-type: x proximity;
}

.page-about .ab-axis-list li {
  scroll-snap-align: start;
  flex: 0 0 auto;
}

.page-about .ab-axis-list a {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  min-width: 64px;
  padding: 6px 12px;
  border: 2px solid var(--line);
  background: var(--ink-800);
  color: var(--mist);
  font-size: 13px;
  letter-spacing: .06em;
  text-decoration: none;
  transition: border-color var(--ease), color var(--ease), background var(--ease);
}

.page-about .ab-axis-list a:hover,
.page-about .ab-axis-list a:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
  background: var(--ink-900);
}

.page-about .ab-nodes {
  display: grid;
  gap: clamp(16px, 2.6vw, 26px);
  min-width: 0;
}

.page-about .ab-node {
  position: relative;
  background: var(--ink-800);
  border: var(--ab-rule);
  border-left: 6px solid var(--signal);
  padding: var(--ab-pad);
  min-width: 0;
  transition: box-shadow var(--ease), border-color var(--ease), background var(--ease);
}

.page-about .ab-node:hover {
  background: var(--ink-700);
}

.page-about .ab-node:target {
  border-color: var(--signal);
  box-shadow: 8px 8px 0 rgba(255, 107, 42, .28);
}

.page-about .ab-node-year {
  margin: 0;
  font-size: clamp(38px, 9vw, 68px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.03em;
  color: var(--warm);
  opacity: .92;
}

.page-about .ab-node > p {
  color: var(--mist);
  font-size: 15.5px;
}

.page-about .ab-node-note {
  font-size: 12.5px;
  letter-spacing: .02em;
  color: var(--cyan);
  line-height: 1.7;
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  margin-top: 0;
  transition: max-height 180ms ease, opacity 180ms ease, margin-top 180ms ease;
}

.page-about .ab-node-note::before {
  content: "▸ ";
}

.page-about .ab-node:hover .ab-node-note,
.page-about .ab-node:focus-within .ab-node-note {
  max-height: 6em;
  opacity: 1;
  margin-top: 14px;
}

.page-about .ab-fig {
  margin: clamp(16px, 2.6vw, 22px) 0 0;
}

.page-about .ab-fig img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 2px solid var(--line-strong);
}

.page-about .ab-fig figcaption {
  margin-top: 8px;
  font-size: 11.5px;
  letter-spacing: .04em;
  color: var(--mist-dim);
  line-height: 1.6;
}

/* ---------- 原则 ---------- */
.page-about .ab-rules {
  background: linear-gradient(180deg, rgba(17, 24, 39, .9), rgba(9, 14, 36, 1));
  border-top: 2px solid var(--line);
  border-bottom: 2px solid var(--line);
}

.page-about .ab-rules-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.page-about .ab-rule {
  border: var(--ab-rule);
  background: var(--ink-900);
  padding: var(--ab-pad);
  transition: border-color var(--ease), background var(--ease), transform var(--ease);
}

.page-about .ab-rule:hover,
.page-about .ab-rule:focus-within {
  border-color: var(--cyan);
  background: var(--ink-800);
  transform: translate(-2px, -2px);
}

.page-about .ab-rule-no {
  margin: 0;
  font-size: 11.5px;
  letter-spacing: .18em;
  color: var(--signal);
}

.page-about .ab-rule p {
  color: var(--mist);
  font-size: 15px;
}

/* ---------- 团队 ---------- */
.page-about .ab-team-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(20px, 3.6vw, 40px);
  align-items: start;
}

.page-about .ab-team-intro > p {
  color: var(--mist);
  font-size: 15px;
}

.page-about .ab-team-list {
  display: grid;
  gap: 10px;
}

.page-about .ab-team-item {
  border: var(--ab-rule);
  background: var(--ink-800);
  transition: border-color var(--ease);
}

.page-about .ab-team-item[open] {
  border-color: var(--line-strong);
}

.page-about .ab-team-item summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-height: 52px;
  padding: 12px 16px;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  color: var(--warm);
}

.page-about .ab-team-item summary::-webkit-details-marker {
  display: none;
}

.page-about .ab-team-item summary::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--cyan);
}

.page-about .ab-team-item[open] summary::after {
  content: "–";
  color: var(--signal);
}

.page-about .ab-team-item summary:hover {
  color: var(--cyan);
}

.page-about .ab-team-item p {
  margin: 0;
  padding: 0 16px 16px;
  color: var(--mist);
  font-size: 14.5px;
  line-height: 1.8;
}

/* ---------- 年度回顾（暖纸面板） ---------- */
.page-about .ab-review-panel {
  background: var(--paper);
  color: var(--ink-900);
  border: 2px solid var(--ink-900);
  box-shadow: 10px 10px 0 var(--signal);
  padding: clamp(20px, 4vw, 44px);
}

.page-about .ab-review-panel .eyebrow {
  color: #a8400e;
}

.page-about .ab-review-panel h2 {
  color: var(--ink-900);
}

.page-about .ab-review-panel h3 {
  color: var(--ink-900);
  font-size: clamp(16px, 2.2vw, 20px);
}

.page-about .ab-review-panel p {
  color: var(--ink-800);
  font-size: 15px;
}

.page-about .ab-review-lede {
  max-width: 44em;
}

.page-about .ab-fig--wide img {
  border-color: var(--ink-900);
}

.page-about .ab-review-panel .ab-fig figcaption {
  color: #4a5265;
}

.page-about .ab-steps {
  list-style: none;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .ab-step {
  border-left: 6px solid var(--signal);
  background: rgba(9, 14, 36, .07);
  padding: 12px 14px;
  transition: background var(--ease), border-color var(--ease);
}

.page-about .ab-step:hover {
  background: rgba(9, 14, 36, .12);
  border-left-color: var(--ink-900);
}

.page-about .ab-step-year {
  margin: 0;
  font-size: 12px;
  letter-spacing: .16em;
  color: #a8400e;
}

.page-about .ab-step p {
  margin: 6px 0 0;
}

.page-about .ab-figs {
  list-style: none;
  margin: clamp(24px, 4vw, 34px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.page-about .ab-fig-item {
  border-top: 3px solid var(--ink-900);
  padding-top: 10px;
}

.page-about .ab-fig-num {
  display: block;
  font-size: clamp(20px, 3.4vw, 28px);
  font-weight: 700;
  letter-spacing: -.02em;
  color: var(--ink-900);
}

.page-about .ab-fig-label {
  display: block;
  margin-top: 4px;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--ink-800);
}

/* ---------- 下一步 ---------- */
.page-about .ab-next-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.page-about .ab-next-item {
  border: var(--ab-rule);
  background: var(--ink-800);
  padding: var(--ab-pad);
  transition: border-color var(--ease), background var(--ease);
}

.page-about .ab-next-item:hover {
  border-color: var(--cyan);
  background: var(--ink-700);
}

.page-about .ab-next-no {
  margin: 0;
  font-size: 11.5px;
  letter-spacing: .18em;
  color: var(--cyan);
}

.page-about .ab-next-item p {
  color: var(--mist);
  font-size: 14.5px;
}

.page-about .ab-cta {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
  margin-top: clamp(24px, 4vw, 40px);
  padding: clamp(20px, 3.4vw, 34px);
  border: 2px solid var(--signal);
  background: var(--ink-800);
}

.page-about .ab-cta h3 {
  margin: 0;
}

.page-about .ab-cta p {
  color: var(--mist);
  font-size: 15px;
  max-width: 40em;
}

.page-about .ab-cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

/* ---------- 断点 ---------- */
@media (max-width: 899px) {
  .page-about .ab-node-note {
    max-height: none;
    opacity: 1;
    margin-top: 14px;
  }

  .page-about .ab-rule:hover {
    transform: none;
  }
}

@media (min-width: 720px) {
  .page-about .ab-rules-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

  .page-about .ab-node:nth-child(even) {
    margin-left: clamp(16px, 4vw, 56px);
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero-grid {
    grid-template-columns: 7fr 5fr;
    gap: clamp(28px, 4vw, 56px);
  }

  .page-about .ab-hero-visual {
    align-self: start;
  }

  .page-about .ab-team-grid {
    grid-template-columns: 5fr 6fr;
  }

  .page-about .ab-step:nth-child(1) {
    width: 100%;
  }

  .page-about .ab-step:nth-child(2) {
    width: 78%;
  }

  .page-about .ab-step:nth-child(3) {
    width: 56%;
  }

  .page-about .ab-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
  }
}

@media (min-width: 960px) {
  .page-about .ab-timeline-grid {
    grid-template-columns: 148px minmax(0, 1fr);
    gap: clamp(20px, 3vw, 40px);
  }

  .page-about .ab-axis {
    position: sticky;
    top: 96px;
    align-self: start;
  }

  .page-about .ab-axis-list {
    flex-direction: column;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .ab-axis-list a {
    justify-content: flex-start;
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
  }
}