.page-about {
  --about-rail-w: 196px;
  background: var(--bg);
  color: var(--text);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: calc(var(--header-h) + 44px) 0 52px;
  background:
    radial-gradient(880px 420px at 82% -12%, rgba(138, 107, 255, 0.18), transparent 62%),
    radial-gradient(660px 360px at 2% 10%, rgba(56, 225, 208, 0.11), transparent 60%),
    var(--bg);
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
  margin-top: 26px;
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  max-width: 16em;
}

.page-about .about-hero__lede {
  margin-top: 18px;
  max-width: 34em;
  color: var(--muted);
}

.page-about .about-hero__facts {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
}

.page-about .about-hero__figure {
  margin: 0;
  min-width: 0;
}

.page-about .about-hero__media {
  border: 1px solid var(--line);
  box-shadow: 0 0 0 6px rgba(30, 42, 62, 0.28);
}

.page-about .sb-media {
  position: relative;
  width: 100%;
  overflow: hidden;
}

.page-about .sb-media__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

/* ---------- 布局骨架 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 36px;
  padding-top: 48px;
  padding-bottom: 72px;
}

.page-about .about-rail {
  display: none;
}

.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 56px;
  min-width: 0;
}

/* ---------- 章节头 ---------- */
.page-about .about-chapter {
  min-width: 0;
  scroll-margin-top: calc(var(--header-h) + 24px);
}

.page-about .about-chapter__head {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding-bottom: 14px;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--line);
}

.page-about .about-chapter__head::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 52px;
  height: 2px;
  background: var(--cyan);
}

.page-about .about-chapter__idx {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--violet);
  flex: none;
}

.page-about .about-chapter__head .sb-h2 {
  margin: 0;
}

.page-about .about-chapter__body {
  min-width: 0;
}

.page-about .about-lede {
  color: var(--text);
  font-size: 17px;
}

.page-about .about-chapter__body .sb-text + .sb-text {
  margin-top: 16px;
}

.page-about .about-inline-link {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(56, 225, 208, 0.4);
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .about-inline-link:hover,
.page-about .about-inline-link:focus-visible {
  border-bottom-color: var(--cyan);
  color: var(--text);
}

/* ---------- 数据条 ---------- */
.page-about .about-stats {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
}

/* ---------- 归档节奏 ---------- */
.page-about .about-chapter__body--split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

.page-about .about-archive__figure {
  margin: 0;
  min-width: 0;
}

.page-about .about-archive__note {
  margin-top: 22px;
}

.page-about .about-archive__note p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--text);
}

/* ---------- 团队分工 ---------- */
.page-about .about-team {
  margin-top: 28px;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .about-team__card {
  position: relative;
  min-width: 0;
  padding: 24px 22px 20px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 2px solid var(--cyan);
  transition:
    border-color var(--dur) var(--ease),
    background-color var(--dur) var(--ease),
    transform var(--dur) var(--ease);
}

.page-about .about-team__card:nth-child(2) {
  border-top-color: var(--violet);
}

.page-about .about-team__card:nth-child(3) {
  border-top-color: var(--amber);
}

.page-about .about-team__card:hover,
.page-about .about-team__card:focus-within {
  background: var(--raised);
  transform: translateY(-2px);
  border-left-color: var(--cyan);
  border-right-color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .about-team__count {
  display: block;
  font-family: var(--font-mono);
  font-size: 48px;
  line-height: 1;
  font-weight: 600;
  letter-spacing: -0.03em;
  color: var(--cyan);
}

.page-about .about-team__card:nth-child(2) .about-team__count {
  color: var(--violet);
}

.page-about .about-team__card:nth-child(3) .about-team__count {
  color: var(--amber);
}

.page-about .about-team__card .sb-h3 {
  margin: 14px 0 10px;
}

.page-about .about-team__card .sb-text {
  font-size: 15px;
  color: var(--muted);
}

.page-about .about-team__out {
  margin: 18px 0 0;
  padding-top: 14px;
  border-top: 1px dashed var(--line);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.8;
  letter-spacing: 0.02em;
  color: var(--faint);
  transition: color var(--dur) var(--ease);
}

.page-about .about-team__card:hover .about-team__out,
.page-about .about-team__card:focus-within .about-team__out {
  color: var(--cyan);
}

/* ---------- 内容来源 ---------- */
.page-about .about-source__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

.page-about .about-source__figure {
  margin: 0;
  min-width: 0;
}

.page-about .about-flow {
  margin-top: 32px;
  padding: 22px 18px 16px;
  background: var(--panel);
  border: 1px solid var(--line);
}

.page-about .about-flow__cap {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--faint);
}

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

.page-about .about-flow__node rect {
  fill: var(--raised);
  stroke: var(--line);
}

.page-about .about-flow__node text {
  fill: var(--text);
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 600;
}

.page-about .about-flow__link line {
  stroke: var(--line);
  stroke-width: 2;
}

.page-about .about-flow__link polygon {
  fill: var(--cyan);
}

/* ---------- 版本演进 ---------- */
.page-about .about-lines {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  position: relative;
}

.page-about .about-lines::before {
  content: "";
  position: absolute;
  left: 30px;
  top: 40px;
  bottom: 40px;
  width: 1px;
  background: linear-gradient(to bottom, var(--cyan), var(--line) 45%);
}

.page-about .about-lines__item {
  position: relative;
  display: grid;
  grid-template-columns: 62px minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.page-about .about-lines__item + .about-lines__item {
  margin-top: 32px;
}

.page-about .about-lines__mark {
  position: relative;
  z-index: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 62px;
  height: 34px;
  background: var(--panel);
  border: 1px solid var(--line);
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .about-lines__item:hover .about-lines__mark {
  border-color: var(--cyan);
  background: var(--raised);
}

.page-about .about-lines__content {
  min-width: 0;
  padding-top: 2px;
}

.page-about .about-lines__content .sb-h3 {
  margin: 0 0 8px;
}

.page-about .about-lines__content .sb-text {
  font-size: 15px;
  color: var(--muted);
}

/* ---------- 一起做事 ---------- */
.page-about .about-cta {
  padding: 26px 22px 24px;
  background: linear-gradient(160deg, var(--raised) 0%, var(--panel) 72%);
  border: 1px solid var(--line);
  border-left: 3px solid var(--cyan);
}

.page-about .about-cta .sb-text {
  color: var(--muted);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.page-about .about-signoff {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 34px;
}

.page-about .about-signoff__rule {
  display: block;
  width: 46px;
  height: 2px;
  background: var(--line);
  flex: none;
}

.page-about .about-signoff p {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--faint);
}

/* ---------- 平板 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero {
    padding: calc(var(--header-h) + 60px) 0 68px;
  }

  .page-about .about-hero__facts,
  .page-about .about-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
  }

  .page-about .about-team {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .about-team__card:first-child {
    grid-column: span 2;
  }

  .page-about .about-cta {
    padding: 32px 30px 30px;
  }

  .page-about .about-lines__item {
    grid-template-columns: 76px minmax(0, 1fr);
    gap: 22px;
  }

  .page-about .about-lines__mark {
    width: 76px;
  }

  .page-about .about-lines::before {
    left: 37px;
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 1024px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 48px;
    align-items: center;
  }

  .page-about .about-layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 52px;
    padding-top: 72px;
    padding-bottom: 96px;
  }

  .page-about .about-rail {
    display: block;
    position: sticky;
    top: calc(var(--header-h) + 28px);
    align-self: start;
  }

  .page-about .about-rail__title {
    margin: 0;
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: 0.16em;
    color: var(--faint);
    text-transform: uppercase;
  }

  .page-about .about-rail__list {
    list-style: none;
    margin: 14px 0 0;
    padding: 0;
    display: grid;
    gap: 2px;
  }

  .page-about .about-rail__item a {
    display: block;
    padding: 9px 0 9px 16px;
    border-left: 2px solid var(--line);
    color: var(--muted);
    font-size: 14px;
    line-height: 1.4;
    text-decoration: none;
    transition:
      color var(--dur) var(--ease),
      border-color var(--dur) var(--ease),
      padding-left var(--dur) var(--ease);
  }

  .page-about .about-rail__item a:hover,
  .page-about .about-rail__item a:focus-visible {
    color: var(--text);
    border-left-color: var(--faint);
  }

  .page-about .about-rail__item[data-active] a {
    color: var(--text);
    border-left-color: var(--cyan);
    padding-left: 21px;
  }

  .page-about .about-body {
    gap: 76px;
  }

  .page-about .about-chapter__body--split {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .about-team {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
  }

  .page-about .about-team__card:first-child {
    grid-column: auto;
  }

  .page-about .about-source__grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .about-flow {
    padding: 26px 26px 20px;
  }

  .page-about .about-cta {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    gap: 32px;
    padding: 34px 36px;
  }

  .page-about .about-cta .sb-text:first-child {
    grid-column: 1;
  }

  .page-about .about-cta .sb-text:nth-child(2) {
    grid-column: 1;
  }

  .page-about .about-cta__actions {
    grid-column: 2;
    grid-row: 1 / span 2;
    margin-top: 0;
    flex-direction: column;
    align-items: stretch;
  }
}

@media (min-width: 1280px) {
  .page-about {
    --about-rail-w: 216px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-team__card,
  .page-about .about-team__out,
  .page-about .about-lines__mark,
  .page-about .about-inline-link,
  .page-about .about-rail__item a {
    transition: none;
  }

  .page-about .about-team__card:hover,
  .page-about .about-team__card:focus-within {
    transform: none;
  }
}