.page-about {
  position: relative;
  display: block;
  overflow-x: clip;
  background:
    radial-gradient(1100px 620px at 80% -8%, rgba(75, 59, 122, 0.40), transparent 64%),
    radial-gradient(840px 560px at 0% 20%, rgba(31, 143, 191, 0.20), transparent 68%);
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumb {
  padding-top: 26px;
}

.page-about .about-crumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--tx-3);
}

.page-about .about-crumb li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--line-strong);
}

.page-about .about-crumb a {
  color: var(--tx-2);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-crumb a:hover,
.page-about .about-crumb a:focus-visible {
  color: var(--c-lake-mist);
  border-bottom-color: var(--c-lake-mist);
}

.page-about .about-crumb [aria-current="page"] {
  color: var(--c-data);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  margin-top: 22px;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero__media {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.page-about .about-hero__media img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 42%;
  opacity: 0.42;
  filter: saturate(0.85) contrast(1.06);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background: linear-gradient(180deg, rgba(6, 16, 32, 0.34) 0%, rgba(6, 16, 32, 0.80) 58%, rgba(6, 16, 32, 0.96) 100%);
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 2;
  padding: clamp(58px, 9vw, 116px) 0 clamp(46px, 6vw, 76px);
}

.page-about .about-hero__title {
  margin: 18px 0 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(38px, 7.4vw, 68px);
  line-height: 0.98;
  letter-spacing: -0.02em;
  color: var(--tx-1);
}

.page-about .about-hero__title span {
  display: block;
  margin-top: 0.12em;
  background: linear-gradient(96deg, var(--c-lake-mist) 0%, var(--c-data) 58%, var(--c-dusk-light) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.page-about .about-hero__lead {
  max-width: 58ch;
  margin: 22px 0 0;
  font-size: 17px;
  line-height: 1.78;
  color: var(--tx-2);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px 16px;
  margin-top: 36px;
  padding-top: 26px;
  border-top: 1px solid var(--line);
}

.page-about .fact__num {
  display: block;
  font-family: var(--font-display);
  font-size: clamp(32px, 5vw, 44px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--tx-1);
}

.page-about .fact__label {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--tx-3);
}

/* ---------- 章节骨架 ---------- */
.page-about .section {
  padding: clamp(54px, 7vw, 92px) 0;
}

.page-about .chapter-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
}

.page-about .chapter-tag {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line-strong);
}

.page-about .chapter-tag__no {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--c-data);
}

.page-about .chapter-tag__label {
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--tx-3);
}

.page-about .chapter-lead {
  max-width: 54ch;
  margin: 18px 0 0;
  font-size: 18px;
  line-height: 1.72;
  color: var(--tx-1);
}

.page-about .chapter-body > p {
  max-width: 68ch;
  margin: 16px 0 0;
  line-height: 1.78;
  color: var(--tx-2);
}

/* ---------- 看台视角 ---------- */
.page-about .principle-list {
  display: grid;
  gap: 0;
  margin: 32px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.page-about .principle-list li {
  display: grid;
  gap: 6px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .principle-list__k {
  font-family: var(--font-display);
  font-size: 21px;
  letter-spacing: 0.02em;
  line-height: 1.2;
  color: var(--c-lake-mist);
}

.page-about .principle-list p {
  margin: 0;
  line-height: 1.72;
  color: var(--tx-2);
}

/* ---------- 发展历程 ---------- */
.page-about .timeline-visual {
  margin: 34px 0 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

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

.page-about .track {
  position: relative;
  list-style: none;
  margin: 44px 0 0;
  padding: 0 0 0 34px;
}

.page-about .track::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: linear-gradient(180deg, var(--c-lake) 0%, var(--c-dusk-light) 56%, rgba(168, 214, 232, 0.18) 100%);
}

.page-about .track__item {
  position: relative;
  padding: 0 0 36px;
  outline: none;
  border-radius: 6px;
}

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

.page-about .track__item:focus-visible {
  outline: 2px solid var(--c-lake);
  outline-offset: 8px;
}

.page-about .track__node {
  position: absolute;
  left: -31px;
  top: 4px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--c-sky);
  border: 2px solid var(--c-lake);
  box-shadow: 0 0 0 4px rgba(31, 143, 191, 0.16);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .track__node--data {
  border-color: var(--c-data);
  box-shadow: 0 0 0 4px rgba(127, 227, 212, 0.16);
}

.page-about .track__node--dusk {
  border-color: var(--c-dusk-light);
  box-shadow: 0 0 0 4px rgba(154, 138, 203, 0.20);
}

.page-about .track__node--hoop {
  border-color: var(--c-hoop);
  box-shadow: 0 0 0 4px rgba(240, 135, 46, 0.18);
}

.page-about .track__item:hover .track__node,
.page-about .track__item:focus-within .track__node {
  transform: scale(1.28);
}

.page-about .track__year {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--c-data);
}

.page-about .track__title {
  margin: 8px 0 0;
  font-family: var(--font-display);
  font-size: clamp(22px, 3.2vw, 28px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  color: var(--tx-1);
}

.page-about .track__text {
  max-width: 62ch;
  margin: 9px 0 0;
  line-height: 1.72;
  color: var(--tx-2);
}

.page-about .track__more {
  max-width: 62ch;
  margin: 8px 0 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--tx-2);
  opacity: 0.82;
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: 34px;
}

.page-about .team-card {
  padding: 22px 20px 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(158deg, rgba(31, 143, 191, 0.13), rgba(75, 59, 122, 0.10));
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .team-card:hover,
.page-about .team-card:focus-within {
  transform: translateY(-4px);
  border-color: var(--line-strong);
}

.page-about .team-card__num {
  display: block;
  font-family: var(--font-display);
  font-size: 40px;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--c-lake-mist);
}

.page-about .team-card__title {
  margin: 12px 0 0;
  font-size: 16px;
  line-height: 1.4;
  color: var(--tx-1);
}

.page-about .team-card p {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--tx-2);
}

.page-about .team-visual {
  margin: 30px 0 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

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

.page-about .team-visual .media__caption {
  padding: 14px 18px 16px;
  font-size: 13px;
  line-height: 1.65;
  color: var(--tx-3);
  border-top: 1px solid var(--line);
}

/* ---------- 横向数据带 ---------- */
.page-about .about-band {
  position: relative;
  padding: clamp(46px, 6vw, 76px) 0;
  background: var(--c-paper);
  color: var(--paper-tx-1);
}

.page-about .about-band::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  background: linear-gradient(180deg, var(--c-lake) 0%, var(--c-dusk) 60%, var(--c-hoop) 100%);
}

.page-about .band__eyebrow {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--paper-tx-2);
}

.page-about .band-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 26px 18px;
  margin-top: 24px;
}

.page-about .band-item__num {
  display: block;
  font-family: var(--font-display);
  font-size: clamp(38px, 5.4vw, 56px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--c-lake-deep);
}

.page-about .band-item__label {
  display: block;
  margin-top: 10px;
  font-size: 14px;
  line-height: 1.5;
  color: var(--paper-tx-2);
}

.page-about .band__note {
  max-width: 78ch;
  margin: 32px 0 0;
  padding-top: 20px;
  border-top: 1px solid rgba(10, 26, 47, 0.12);
  font-size: 15px;
  line-height: 1.75;
  color: var(--paper-tx-2);
}

/* ---------- 双轨建设 ---------- */
.page-about .dual-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  margin-top: 32px;
}

.page-about .dual-card {
  padding: 26px 22px 28px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: rgba(10, 26, 47, 0.55);
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .dual-card:hover,
.page-about .dual-card:focus-within {
  transform: translateY(-4px);
  border-color: var(--line-strong);
}

.page-about .dual-card--m {
  border-top: 3px solid var(--c-hoop);
}

.page-about .dual-card--p {
  border-top: 3px solid var(--c-lake);
}

.page-about .dual-card__tag {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--tx-3);
}

.page-about .dual-card__title {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-size: clamp(21px, 3vw, 26px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--tx-1);
}

.page-about .dual-card ul {
  display: grid;
  gap: 11px;
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .dual-card li {
  position: relative;
  padding-left: 18px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--tx-2);
}

.page-about .dual-card li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--c-lake-mist);
}

.page-about .dual-card--m li::before {
  background: var(--c-hoop);
}

.page-about .dual-card--p li::before {
  background: var(--c-lake);
}

.page-about .dual-bridge {
  margin: 26px 0 0;
  padding: 20px 22px;
  border-left: 2px solid var(--c-dusk-light);
  border-radius: 0 var(--radius) var(--radius) 0;
  background: rgba(75, 59, 122, 0.18);
  line-height: 1.78;
  color: var(--tx-2);
}

/* ---------- 覆盖与合作 ---------- */
.page-about .reach-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

/* ---------- 站点信息 ---------- */
.page-about .about-meta {
  margin-top: clamp(26px, 4vw, 48px);
  padding: clamp(46px, 6vw, 72px) 0 clamp(58px, 8vw, 96px);
  border-top: 1px solid var(--line);
}

.page-about .about-meta__title {
  margin: 0 0 22px;
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--tx-3);
}

.page-about .meta-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  margin: 0;
}

.page-about .meta-list > div {
  display: flex;
  align-items: baseline;
  gap: 16px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .meta-list dt {
  flex: 0 0 86px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--tx-3);
}

.page-about .meta-list dd {
  margin: 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--tx-2);
}

.page-about .about-meta__contact {
  margin: 26px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--tx-3);
}

.page-about .about-meta__contact a {
  color: var(--c-lake);
  text-decoration: none;
  border-bottom: 1px solid rgba(31, 143, 191, 0.45);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-meta__contact a:hover,
.page-about .about-meta__contact a:focus-visible {
  color: var(--c-data);
  border-bottom-color: var(--c-data);
}

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

  .page-about .about-hero__facts {
    gap: 24px;
  }

  .page-about .principle-list li {
    grid-template-columns: 104px minmax(0, 1fr);
    gap: 24px;
    align-items: baseline;
  }

  .page-about .meta-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 48px;
  }
}

@media (min-width: 860px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .band-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0;
    margin-top: 28px;
  }

  .page-about .band-item {
    padding: 0 26px;
    border-left: 1px solid rgba(10, 26, 47, 0.14);
  }

  .page-about .band-item:first-child {
    padding-left: 0;
    border-left: 0;
  }

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

@media (min-width: 960px) {
  .page-about .chapter-grid {
    grid-template-columns: 156px minmax(0, 1fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .chapter-tag {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    position: sticky;
    top: calc(var(--bar-h) + 28px);
  }

  .page-about .track {
    margin-left: 34px;
    padding-left: 40px;
  }

  .page-about .track__node {
    left: -37px;
  }

  .page-about .track__more {
    max-height: 0;
    margin-top: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height 240ms var(--ease), opacity 180ms var(--ease), margin-top 240ms var(--ease);
  }

  .page-about .track__item:hover .track__more,
  .page-about .track__item:focus-within .track__more {
    max-height: 160px;
    margin-top: 9px;
    opacity: 1;
  }

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

@media (min-width: 1200px) {
  .page-about .track {
    margin-left: 56px;
    padding-left: 48px;
  }

  .page-about .timeline-visual {
    margin-left: 212px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .team-card,
  .page-about .dual-card,
  .page-about .track__node,
  .page-about .track__more {
    transition: none;
  }

  .page-about .track__more {
    max-height: none;
    opacity: 0.82;
    overflow: visible;
  }
}