.page-about {
  --ab-gap: clamp(20px, 4vw, 56px);
  --ab-hair: rgba(53, 224, 214, .28);
  --ab-pad: clamp(48px, 9vw, 104px);
  color: var(--bd-white);
  background:
    radial-gradient(900px 520px at 84% -6%, rgba(53, 224, 214, .10), transparent 62%),
    radial-gradient(720px 460px at 6% 18%, rgba(255, 90, 31, .07), transparent 60%),
    var(--bd-deep);
  overflow-x: hidden;
}

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

.page-about figure {
  margin: 0;
}

/* ---------- 面包屑 ---------- */

.page-about .ab-crumb {
  padding-top: clamp(88px, 12vh, 128px);
}

/* ---------- 首屏 ---------- */

.page-about .ab-hero {
  padding: clamp(20px, 3vw, 36px) 0 clamp(48px, 8vw, 96px);
}

.page-about .ab-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 5vw, 64px);
  align-items: start;
}

.page-about .ab-hero__side {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--bd-line);
}

.page-about .ab-hero__side-label {
  margin: 0;
  font-family: var(--bd-mono);
  font-size: 11px;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--bd-cyan);
}

.page-about .ab-hero__year {
  margin: 0;
  font-family: var(--bd-mono);
  font-weight: 700;
  font-size: clamp(64px, 15vw, 118px);
  line-height: .85;
  letter-spacing: -.05em;
  color: var(--bd-white);
}

.page-about .ab-hero__side-note {
  margin: 4px 0 0;
  max-width: 30ch;
  font-size: 13px;
  line-height: 1.7;
  color: var(--bd-grey);
}

.page-about .ab-hero__title {
  margin: 14px 0 0;
  max-width: 20ch;
  letter-spacing: -.02em;
}

.page-about .ab-hero__lead {
  margin: 22px 0 0;
  max-width: 34ch;
  font-size: 17px;
  line-height: 1.75;
  color: var(--bd-grey);
}

.page-about .ab-hero__tags {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 28px;
  border-top: 1px solid var(--bd-line);
  padding-top: 18px;
}

.page-about .ab-hero__tags li {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  font-size: 13px;
  letter-spacing: .04em;
  color: var(--bd-grey);
}

.page-about .ab-hero__tag-num {
  font-family: var(--bd-mono);
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--bd-white);
}

/* ---------- 章节通用 ---------- */

.page-about .ab-section {
  position: relative;
  padding: var(--ab-pad) 0;
}

.page-about .ab-section + .ab-section {
  border-top: 1px solid var(--bd-line);
}

.page-about .ab-head {
  max-width: 68ch;
  margin-bottom: clamp(24px, 4vw, 48px);
}

.page-about .ab-head .bd-title {
  margin: 10px 0 14px;
}

.page-about .ab-head .bd-prose {
  margin: 0;
  color: var(--bd-grey);
}

/* ---------- 发展阶段 ---------- */

.page-about .ab-stage__media {
  margin-bottom: clamp(32px, 5vw, 56px);
}

.page-about .ab-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
}

.page-about .ab-tl__axis {
  display: none;
  position: absolute;
  left: 4px;
  top: 34px;
  bottom: 34px;
  width: 2px;
  height: auto;
}

.page-about .ab-tl__item {
  position: relative;
  padding: 22px 0 22px 26px;
  border-bottom: 1px solid var(--bd-line);
}

.page-about .ab-tl__item:last-child {
  border-bottom: none;
}

.page-about .ab-tl__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 34px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--bd-orange);
  box-shadow: 0 0 0 4px rgba(255, 90, 31, .14);
}

.page-about .ab-tl__mark {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin-bottom: 8px;
}

.page-about .ab-tl__ver {
  font-family: var(--bd-mono);
  font-size: clamp(26px, 6vw, 40px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--bd-white);
}

.page-about .ab-tl__yr {
  font-family: var(--bd-mono);
  font-size: 11px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--bd-cyan);
}

.page-about .ab-tl__body h3 {
  margin: 0 0 10px;
}

.page-about .ab-tl__body p {
  margin: 0;
  max-width: 52ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--bd-grey);
}

.page-about .ab-tl__more {
  margin-top: 14px;
  padding-left: 0;
  border-left: 2px solid transparent;
  transition: border-color .2s var(--bd-ease), padding-left .2s var(--bd-ease);
}

.page-about .ab-tl__more[open] {
  padding-left: 14px;
  border-left-color: var(--bd-cyan);
}

.page-about .ab-tl__more summary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  list-style: none;
  cursor: pointer;
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--bd-cyan);
}

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

.page-about .ab-tl__more summary::after {
  content: "＋";
  font-size: 12px;
  line-height: 1;
}

.page-about .ab-tl__more[open] summary::after {
  content: "－";
}

.page-about .ab-tl__more p {
  margin: 10px 0 0;
  max-width: 50ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--bd-grey);
}

/* ---------- 数据体系 ---------- */

.page-about .ab-data__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 5vw, 64px);
  align-items: start;
}

.page-about .ab-data__facts {
  margin: 0;
  display: grid;
  gap: 0;
}

.page-about .ab-data__fact {
  display: grid;
  gap: 6px;
  padding: 22px 0;
  border-top: 1px solid var(--bd-line);
}

.page-about .ab-data__fact dt {
  font-family: var(--bd-mono);
  font-size: clamp(24px, 4vw, 34px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.01em;
  color: var(--bd-cyan);
}

.page-about .ab-data__fact dd {
  margin: 0;
  max-width: 48ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--bd-grey);
}

.page-about .ab-data__aside {
  display: grid;
  gap: 18px;
  align-content: start;
}

.page-about .ab-data__note {
  padding: 20px 22px;
  border-radius: var(--bd-radius);
}

.page-about .ab-data__note p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--bd-grey);
}

/* ---------- 团队 ---------- */

.page-about .ab-team__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  border-top: 1px solid var(--bd-line);
}

.page-about .ab-team__card {
  position: relative;
  padding: clamp(24px, 4vw, 40px) 0;
  transition: transform .25s var(--bd-ease);
}

.page-about .ab-team__card + .ab-team__card {
  border-top: 1px solid var(--bd-line);
}

.page-about .ab-team__card::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--bd-cyan), transparent 70%);
  opacity: 0;
  transition: opacity .25s var(--bd-ease);
}

.page-about .ab-team__card:hover {
  transform: translateY(-4px);
}

.page-about .ab-team__card:hover::after {
  opacity: 1;
}

.page-about .ab-team__loc {
  margin: 0;
  font-family: var(--bd-mono);
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--bd-cyan);
}

.page-about .ab-team__card h3 {
  margin: 12px 0 12px;
}

.page-about .ab-team__card > p {
  margin: 0;
  max-width: 46ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--bd-grey);
}

.page-about .ab-team__points {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .ab-team__points li {
  position: relative;
  padding-left: 18px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--bd-white);
}

.page-about .ab-team__points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 10px;
  height: 1px;
  background: var(--bd-cyan);
}

.page-about .ab-team__map {
  margin-top: clamp(28px, 5vw, 52px);
}

/* ---------- 合作生态 ---------- */

.page-about .ab-eco__tree {
  position: relative;
  padding-top: 8px;
}

.page-about .ab-eco__root {
  position: relative;
  display: flex;
  justify-content: center;
  margin-bottom: 46px;
}

.page-about .ab-eco__root::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 100%;
  width: 1px;
  height: 46px;
  background: linear-gradient(180deg, var(--ab-hair), transparent);
}

.page-about .ab-eco__branch {
  list-style: none;
  margin: 0;
  padding: 24px 0 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
  position: relative;
}

.page-about .ab-eco__card {
  position: relative;
  padding: 24px 22px;
  background: var(--bd-panel);
  border: 1px solid var(--bd-line);
  border-radius: var(--bd-radius);
  transition: transform .25s var(--bd-ease), border-color .25s var(--bd-ease);
}

.page-about .ab-eco__card:hover {
  transform: translateY(-4px);
  border-color: var(--ab-hair);
}

.page-about .ab-eco__num {
  display: block;
  font-family: var(--bd-mono);
  font-size: 22px;
  font-weight: 700;
  line-height: 1;
  color: var(--bd-orange);
}

.page-about .ab-eco__card h3 {
  margin: 14px 0 10px;
}

.page-about .ab-eco__card p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--bd-grey);
}

/* ---------- 长期记录 ---------- */

.page-about .ab-proof__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--bd-line);
  border: 1px solid var(--bd-line);
  border-radius: var(--bd-radius);
  overflow: hidden;
}

.page-about .ab-proof__item {
  display: grid;
  gap: 10px;
  padding: 26px 24px;
  background: var(--bd-deep);
}

.page-about .ab-proof__num {
  font-family: var(--bd-mono);
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--bd-white);
}

.page-about .ab-proof__txt {
  margin: 0;
  max-width: 34ch;
  font-size: 15px;
  line-height: 1.72;
  color: var(--bd-grey);
}

/* ---------- 收尾 ---------- */

.page-about .ab-cta {
  padding: clamp(48px, 8vw, 96px) 0 clamp(56px, 9vw, 112px);
  border-top: 1px solid var(--bd-line);
  background:
    radial-gradient(680px 340px at 18% 0%, rgba(255, 90, 31, .10), transparent 66%),
    var(--bd-midnight);
}

.page-about .ab-cta h2 {
  margin: 0 0 14px;
  max-width: 26ch;
}

.page-about .ab-cta__text {
  margin: 0;
  max-width: 46ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--bd-grey);
}

.page-about .ab-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .ab-cta__extra {
  margin: 24px 0 0;
  max-width: 52ch;
  font-size: 14px;
  line-height: 1.75;
  color: var(--bd-grey);
}

.page-about .ab-cta__extra a {
  color: var(--bd-cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 224, 214, .4);
  transition: color .15s var(--bd-ease), border-color .15s var(--bd-ease);
}

.page-about .ab-cta__extra a:hover,
.page-about .ab-cta__extra a:focus-visible {
  color: var(--bd-white);
  border-bottom-color: var(--bd-orange);
}

.page-about .ab-cta__extra a:focus-visible,
.page-about .ab-eco__card:focus-within {
  outline: 2px solid var(--bd-cyan);
  outline-offset: 3px;
}

/* ---------- 桌面布局 ---------- */

@media (min-width: 760px) {
  .page-about .ab-proof__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 820px) {
  .page-about .ab-team__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .ab-team__card + .ab-team__card {
    border-top: none;
    border-left: 1px solid var(--ab-hair);
    padding-left: clamp(24px, 3.5vw, 48px);
  }

  .page-about .ab-team__card:first-child {
    padding-right: clamp(24px, 3.5vw, 48px);
  }
}

@media (min-width: 860px) {
  .page-about .ab-tl__axis {
    display: block;
    left: 4px;
  }

  .page-about .ab-tl__item {
    display: grid;
    grid-template-columns: 150px minmax(0, 1fr);
    gap: 32px;
    padding: 30px 0 30px 34px;
  }

  .page-about .ab-tl__item::before {
    top: 36px;
  }

  .page-about .ab-tl__mark {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
    margin-bottom: 0;
  }

  .page-about .ab-tl__yr {
    margin-top: 2px;
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 250px) minmax(0, 1fr);
    gap: clamp(32px, 5vw, 72px);
  }

  .page-about .ab-hero__side {
    position: sticky;
    top: calc(var(--bd-bar) + 32px);
    border-bottom: none;
    border-left: 1px solid var(--bd-line);
    padding: 4px 0 4px 22px;
  }
}

@media (min-width: 940px) {
  .page-about .ab-data__grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, .6fr);
  }
}

@media (min-width: 960px) {
  .page-about .ab-eco__branch {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 24px;
    padding-top: 30px;
  }

  .page-about .ab-eco__branch::before {
    content: "";
    position: absolute;
    top: 0;
    left: 16.66%;
    right: 16.66%;
    height: 1px;
    background: var(--ab-hair);
  }

  .page-about .ab-eco__card::before {
    content: "";
    position: absolute;
    top: -30px;
    left: 50%;
    width: 1px;
    height: 30px;
    background: var(--ab-hair);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-team__card,
  .page-about .ab-eco__card,
  .page-about .ab-tl__more {
    transition: none;
  }
}