.page-about {
  background: var(--paper);
  color: var(--text);
  padding-bottom: clamp(64px, 9vw, 120px);
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumb {
  padding-top: calc(var(--header-h) + 28px);
}

/* ---------- 超大衬线编号 ---------- */
.page-about .about-num {
  display: block;
  font-family: var(--font-serif);
  font-size: clamp(56px, 12vw, 96px);
  line-height: .84;
  letter-spacing: -.045em;
  color: var(--ink-800);
  margin: 0 0 14px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  margin-top: 28px;
}

.page-about .about-hero__head {
  max-width: 900px;
}

.page-about .about-hero h1 {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(28px, 5.4vw, 52px);
  line-height: 1.1;
  letter-spacing: -.02em;
  margin: 0 0 18px;
  color: var(--text);
}

.page-about .about-hero .lede {
  font-size: clamp(16px, 2.1vw, 19px);
  line-height: 1.78;
  color: var(--muted);
  max-width: 64ch;
  margin: 0 0 40px;
}

.page-about .about-hero__figure {
  position: relative;
  margin: 0;
  aspect-ratio: 1600 / 700;
  overflow: hidden;
  background: var(--ink-900);
}

.page-about .about-hero__figure img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(.7) contrast(1.06);
}

.page-about .about-hero__cap {
  position: absolute;
  left: 0;
  bottom: 0;
  margin: 0;
  padding: 10px 16px;
  background: var(--ink-900);
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: var(--t12);
  letter-spacing: .06em;
  max-width: 90%;
}

/* ---------- 主体框架 ---------- */
.page-about .about-shell {
  padding-top: clamp(40px, 6vw, 72px);
}

.page-about .about-toc {
  margin: 0 0 36px;
  padding: 18px 0 0;
  border-top: 1px solid var(--hair-strong);
}

.page-about .about-toc__title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: var(--t12);
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .about-toc ol {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
}

.page-about .about-toc a {
  display: inline-block;
  font-size: var(--t14);
  color: var(--muted);
  text-decoration: none;
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-toc a:hover,
.page-about .about-toc a:focus-visible,
.page-about .about-toc a[aria-current="true"] {
  color: var(--text);
  border-bottom-color: var(--flare);
}

/* ---------- 章节 ---------- */
.page-about .about-sec {
  padding: clamp(36px, 5.5vw, 68px) 0;
  border-top: 1px solid var(--hair);
}

.page-about .about-body > .about-sec:first-of-type {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-sec__grid {
  display: grid;
  gap: 16px;
}

.page-about .about-sec__main h2 {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(22px, 3.6vw, 34px);
  line-height: 1.2;
  letter-spacing: -.02em;
  margin: 0 0 18px;
  color: var(--text);
}

.page-about .about-sec__intro {
  max-width: 68ch;
  margin: 0 0 28px;
  font-size: var(--t16);
  line-height: 1.78;
  color: var(--muted);
}

.page-about .about-sec__main .prose {
  max-width: 68ch;
}

.page-about .about-sec__main .prose p {
  margin: 0 0 1.2em;
  font-size: var(--t16);
  line-height: 1.78;
}

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

/* ---------- 02 图文分栏 ---------- */
.page-about .about-split {
  display: grid;
  gap: 28px;
}

.page-about .about-figure-b,
.page-about .about-figure-c {
  position: relative;
  margin: 0;
  overflow: hidden;
  background: var(--ink-900);
}

.page-about .about-figure-b {
  aspect-ratio: 4 / 3;
}

.page-about .about-figure-c {
  margin-top: 8px;
  aspect-ratio: 7 / 3;
}

.page-about .about-figure-b img,
.page-about .about-figure-c img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(.68) contrast(1.04);
}

.page-about .about-figure-cap {
  position: absolute;
  left: 0;
  bottom: 0;
  margin: 0;
  padding: 8px 14px;
  background: var(--ink-900);
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: var(--t12);
  letter-spacing: .05em;
  max-width: 92%;
}

/* ---------- 03 时间轴 ---------- */
.page-about .about-timeline {
  margin-top: 8px;
}

.page-about .about-timeline__list {
  list-style: none;
  margin: 0;
  padding: 0 0 0 28px;
  position: relative;
}

.page-about .about-timeline__list::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--hair-strong);
}

.page-about .about-timeline__item {
  position: relative;
  padding-bottom: 26px;
}

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

.page-about .about-timeline__dot {
  position: absolute;
  left: -28px;
  top: 5px;
  width: 11px;
  height: 11px;
  background: var(--paper);
  border: 1px solid var(--line);
}

.page-about .about-timeline__item.is-current .about-timeline__dot {
  background: var(--flare);
  border-color: var(--flare);
}

.page-about .about-timeline details > summary {
  list-style: none;
  cursor: pointer;
  outline-offset: 4px;
}

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

.page-about .about-timeline__year {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--t12);
  letter-spacing: .06em;
  color: var(--cyan);
  background: var(--ink-800);
  padding: 4px 8px;
  margin-bottom: 10px;
}

.page-about .about-timeline__name {
  display: block;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: var(--t20);
  letter-spacing: -.01em;
  color: var(--text);
  transition: color var(--dur) var(--ease);
}

.page-about .about-timeline summary:hover .about-timeline__name,
.page-about .about-timeline summary:focus-visible .about-timeline__name {
  color: var(--ink-800);
}

.page-about .about-timeline details > p {
  margin: 10px 0 0;
  max-width: 62ch;
  font-size: var(--t14);
  line-height: 1.78;
  color: var(--muted);
  border-left: 2px solid var(--hair-strong);
  padding-left: 14px;
}

/* ---------- 04 团队 ---------- */
.page-about .about-team {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--steel);
  border: 1px solid var(--steel);
}

.page-about .about-team li {
  background: var(--paper);
  padding: 22px 20px;
}

.page-about .about-team__num {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--t28);
  letter-spacing: .04em;
  line-height: 1;
  color: var(--ink-800);
}

.page-about .about-team__role {
  display: block;
  margin-top: 6px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: var(--t16);
  color: var(--text);
}

.page-about .about-team li p {
  margin: 12px 0 0;
  font-size: var(--t14);
  line-height: 1.72;
  color: var(--muted);
}

/* ---------- 05 数据卡 ---------- */
.page-about .about-stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--steel);
  border: 1px solid var(--steel);
}

.page-about .about-stats li {
  background: var(--mist);
  padding: 22px 20px;
  border-top: 2px solid var(--line);
}

.page-about .about-stats li:first-child {
  border-top-color: var(--flare);
}

.page-about .about-stats__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(26px, 5vw, 38px);
  letter-spacing: .02em;
  line-height: 1;
  color: var(--ink-900);
}

.page-about .about-stats__label {
  display: block;
  margin-top: 10px;
  font-size: var(--t14);
  line-height: 1.6;
  color: var(--muted);
}

.page-about .about-pullquote {
  margin: 28px 0 0;
  max-width: 62ch;
  padding: 4px 0 4px 18px;
  border-left: 2px solid var(--flare);
  font-family: var(--font-serif);
  font-size: clamp(17px, 2.2vw, 20px);
  line-height: 1.7;
  color: var(--ink-800);
}

/* ---------- 07 目标 ---------- */
.page-about .about-goals {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 22px;
}

.page-about .about-goals li {
  display: grid;
  grid-template-columns: 28px minmax(0, 1fr);
  gap: 16px;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--hair);
}

.page-about .about-goals li:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-goals__idx {
  font-family: var(--font-mono);
  font-size: var(--t14);
  letter-spacing: .08em;
  color: var(--flare);
  padding-top: 3px;
}

.page-about .about-goals h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: var(--t20);
  letter-spacing: -.01em;
  color: var(--text);
}

.page-about .about-goals p {
  margin: 0;
  max-width: 62ch;
  font-size: var(--t16);
  line-height: 1.75;
  color: var(--muted);
}

.page-about .about-cta {
  margin-top: 36px;
  padding-top: 28px;
  border-top: 1px solid var(--hair-strong);
  display: grid;
  gap: 18px;
}

.page-about .about-cta p {
  margin: 0;
  max-width: 58ch;
  font-size: var(--t16);
  line-height: 1.75;
  color: var(--muted);
}

.page-about .about-cta .btn {
  justify-self: start;
}

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

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

@media (min-width: 768px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
    gap: 36px;
    align-items: start;
  }

  .page-about .about-figure-c {
    margin-top: 32px;
  }
}

/* ---------- 大屏：编号列 + 正文列 ---------- */
@media (min-width: 900px) {
  .page-about .about-sec__grid {
    grid-template-columns: 140px minmax(0, 1fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .about-sec__aside {
    position: sticky;
    top: calc(var(--header-h) + 32px);
  }
}

/* ---------- 大屏：目录侧栏 + 横向时间轴 ---------- */
@media (min-width: 1000px) {
  .page-about .about-shell {
    display: grid;
    grid-template-columns: 200px minmax(0, 1fr);
    gap: 72px;
    align-items: start;
  }

  .page-about .about-toc {
    position: sticky;
    top: calc(var(--header-h) + 32px);
    margin-bottom: 0;
    padding: 4px 0 0 20px;
    border-top: 0;
    border-left: 1px solid var(--hair-strong);
  }

  .page-about .about-toc ol {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 10px;
  }

  .page-about .about-timeline__list {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 30px;
    padding-left: 0;
  }

  .page-about .about-timeline__list::before {
    left: 0;
    right: 0;
    top: 5px;
    bottom: auto;
    width: auto;
    height: 1px;
  }

  .page-about .about-timeline__item {
    position: relative;
    padding-top: 28px;
    padding-bottom: 0;
  }

  .page-about .about-timeline__dot {
    left: 0;
    top: 0;
  }

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

@media (min-width: 1200px) {
  .page-about .about-shell {
    grid-template-columns: 220px minmax(0, 1fr);
    gap: 96px;
  }
}

/* ---------- 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc a,
  .page-about .about-timeline__name {
    transition: none;
  }
}