.page-about {
  --ab-rail: 176px;
  --ab-gap: 46px;
  --ab-chapter: clamp(68px, 8vw, 112px);
}

.page-about .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

/* ── 页首面包屑 ── */
.page-about .about-topbar {
  padding: 26px 0 0;
}

/* ── 首屏 ── */
.page-about .about-hero {
  padding: clamp(26px, 4.5vw, 52px) 0 clamp(34px, 5vw, 66px);
}

.page-about .about-hero__grid {
  display: grid;
  gap: 30px;
}

.page-about h1 {
  margin: 14px 0 0;
  font-size: clamp(33px, 7vw, 58px);
  line-height: 1.08;
  letter-spacing: -0.022em;
  font-weight: 800;
  color: var(--text-strong);
  text-wrap: balance;
}

.page-about .about-hero__lead {
  margin: 20px 0 0;
  max-width: 46ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--text);
}

.page-about .about-hero__facts {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 26px;
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-hero__facts li {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding-right: 26px;
  border-right: 1px solid var(--line);
}

.page-about .about-hero__facts li:last-child {
  padding-right: 0;
  border-right: 0;
}

.page-about .about-hero__facts .num {
  font-size: 21px;
  font-weight: 700;
  color: var(--cyan);
  line-height: 1;
}

.page-about .about-hero__fl {
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--text-dim);
}

.page-about .about-hero__cta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 30px 0 0;
}

.page-about .about-hero__visual {
  position: relative;
  min-height: 220px;
  aspect-ratio: 4 / 5;
  max-height: 440px;
  border: 1px solid var(--line-violet);
  background:
    radial-gradient(120% 80% at 50% 100%, var(--glow-a), transparent 68%),
    var(--bg-2);
  overflow: hidden;
}

.page-about .about-sky {
  display: block;
  width: 100%;
  height: 100%;
}

/* ── 时间轴 + 内容双栏 ── */
.page-about .about-chronicle {
  display: grid;
  gap: 10px;
}

.page-about .about-rail {
  position: relative;
}

.page-about .about-rail__list {
  display: flex;
  gap: 6px;
  margin: 0;
  padding: 10px 0 14px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .about-rail__list::-webkit-scrollbar {
  display: none;
}

.page-about .about-rail__item {
  flex: 0 0 auto;
}

.page-about .about-rail__link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 7px 13px;
  border: 1px solid var(--line);
  border-radius: var(--r);
  text-decoration: none;
  white-space: nowrap;
  transition: border-color 0.22s var(--ease), color 0.22s var(--ease);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  border-color: var(--line-violet);
}

.page-about .about-rail__year {
  font-size: 12.5px;
  font-weight: 700;
  color: var(--cyan);
}

.page-about .about-rail__name {
  font-size: 13px;
  color: var(--text-dim);
}

.page-about .about-rail__link:hover .about-rail__name {
  color: var(--cream);
}

/* ── 章节 ── */
.page-about .about-flow {
  padding-top: 8px;
}

.page-about .about-chapter {
  padding: var(--ab-chapter) 0;
  border-bottom: 1px solid var(--line-soft);
  scroll-margin-top: calc(var(--hdr-h) + 24px);
}

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

.page-about .about-chapter__head h2 {
  margin: 10px 0 0;
  font-size: clamp(23px, 3.6vw, 33px);
  line-height: 1.2;
  letter-spacing: -0.016em;
  font-weight: 700;
  color: var(--text-strong);
}

.page-about .about-chapter .prose p {
  margin: 0 0 1.05em;
  color: var(--text);
  line-height: 1.78;
}

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

.page-about .about-chapter--paper {
  border-left: 2px solid var(--violet);
  padding-left: clamp(16px, 2.6vw, 32px);
  background: linear-gradient(180deg, rgba(243, 236, 223, 0.055), rgba(243, 236, 223, 0.016));
}

/* ── 图片 ── */
.page-about .figure {
  margin: 26px 0 0;
}

.page-about .about-desk__figure,
.page-about .about-coverage__figure {
  margin-top: 28px;
}

/* ── 版本演进 ── */
.page-about .about-ver {
  margin-top: 26px;
}

.page-about .about-ver__chart {
  display: block;
  width: 100%;
  height: auto;
  overflow: visible;
}

.page-about .about-ver__axis line {
  stroke: var(--line);
  stroke-width: 1;
}

.page-about .about-ver__ticks text {
  fill: var(--text-dim);
  font-family: var(--font-mono);
  font-size: 11px;
}

.page-about .about-ver__line {
  fill: none;
  stroke: var(--violet);
  stroke-width: 2;
  stroke-linejoin: round;
  stroke-linecap: round;
}

.page-about .about-ver__dots circle {
  fill: var(--bg);
  stroke: var(--cyan);
  stroke-width: 2;
  transition: fill 0.22s var(--ease), r 0.22s var(--ease);
}

.page-about .about-ver__dots circle:hover {
  fill: var(--cyan);
  r: 7;
}

.page-about .about-ver__list {
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.page-about .about-ver__item {
  display: grid;
  grid-template-columns: 54px minmax(0, 1fr);
  gap: 3px 14px;
  padding: 15px 0;
  border-bottom: 1px solid var(--line-soft);
  transition: background 0.22s var(--ease);
}

.page-about .about-ver__item:hover {
  background: rgba(122, 59, 255, 0.07);
}

.page-about .about-ver__tag {
  font-size: 15px;
  font-weight: 700;
  color: var(--cyan);
  transition: color 0.22s var(--ease);
}

.page-about .about-ver__item:hover .about-ver__tag {
  color: var(--orange);
}

.page-about .about-ver__when {
  align-self: center;
  font-size: 11.5px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dim);
}

.page-about .about-ver__what {
  grid-column: 2;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--text);
}

/* ── 编辑台清单 ── */
.page-about .about-desk__list {
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  border-left: 1px solid var(--line-violet);
}

.page-about .about-desk__list li {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 14px;
  padding: 9px 0 9px 20px;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--text);
}

.page-about .about-desk__list li::before {
  content: "";
  position: absolute;
  left: -3px;
  top: 18px;
  width: 5px;
  height: 5px;
  background: var(--cyan);
  transform: rotate(45deg);
}

.page-about .about-desk__k {
  flex: 0 0 44px;
  font-size: 12.5px;
  font-weight: 700;
  color: var(--orange);
  letter-spacing: 0.04em;
}

/* ── 团队分段标签 ── */
.page-about .about-team {
  margin-top: 26px;
}

.page-about .about-team .tabs__list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.page-about .about-team .tabs__tab {
  cursor: pointer;
  font-size: 13px;
  padding: 8px 14px;
  border: 1px solid var(--line);
  border-radius: var(--r);
  background: transparent;
  color: var(--text-dim);
  transition: color 0.22s var(--ease), border-color 0.22s var(--ease), background 0.22s var(--ease);
}

.page-about .about-team .tabs__tab:hover {
  border-color: var(--line-violet);
  color: var(--cream);
}

.page-about .about-team .tabs__tab[aria-selected="true"] {
  border-color: var(--violet);
  background: rgba(122, 59, 255, 0.16);
  color: var(--text-strong);
}

.page-about .about-team__panel {
  padding: 22px 0 0;
}

.page-about .about-team__lead {
  margin: 0 0 16px;
  font-size: 15px;
  line-height: 1.78;
  color: var(--text);
  max-width: 62ch;
}

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

.page-about .about-team__list li {
  position: relative;
  padding-left: 20px;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--text-dim);
}

.page-about .about-team__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 8px;
  height: 1px;
  background: var(--cyan);
}

/* ── 覆盖范围统计 ── */
.page-about .about-coverage__stats {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 30px;
  margin: 22px 0 0;
  padding: 14px 0 16px;
  list-style: none;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-coverage__stats li {
  display: flex;
  align-items: baseline;
  gap: 7px;
  font-size: 13.5px;
  color: var(--text-dim);
}

.page-about .about-coverage__stats .num {
  font-size: 22px;
  font-weight: 700;
  color: var(--cyan);
  line-height: 1;
}

/* ── 下一程 ── */
.page-about .about-next__list {
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 2px;
}

.page-about .about-next__item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 16px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-next__item:first-child {
  border-top: 1px solid var(--line-soft);
}

.page-about .about-next__idx {
  grid-row: 1 / span 2;
  font-size: 13px;
  font-weight: 700;
  color: var(--violet);
  letter-spacing: 0.08em;
  padding-top: 4px;
}

.page-about .about-next__item h3 {
  margin: 0;
  font-size: 17px;
  font-weight: 600;
  color: var(--text-strong);
}

.page-about .about-next__item p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.74;
  color: var(--text-dim);
}

.page-about .about-next__close {
  margin: 34px 0 0;
  padding-left: clamp(16px, 2.6vw, 32px);
  border-left: 2px solid var(--orange);
  font-size: 16.5px;
  line-height: 1.76;
  color: var(--text-strong);
  max-width: 60ch;
}

/* ── 继续浏览 ── */
.page-about .about-route {
  display: grid;
  gap: 20px;
  margin-top: clamp(46px, 6vw, 76px);
  padding-top: 28px;
  border-top: 1px solid var(--line);
}

.page-about .about-route__item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 2px 14px;
  text-decoration: none;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line-soft);
  transition: border-color 0.22s var(--ease);
}

.page-about .about-route__item:hover {
  border-color: var(--violet);
}

.page-about .about-route__coord {
  grid-row: 1 / span 2;
  font-size: 12px;
  font-weight: 700;
  color: var(--cyan);
  padding-top: 3px;
}

.page-about .about-route__label {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-strong);
}

.page-about .about-route__hint {
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-dim);
}

/* ── 响应式 ── */
@media (min-width: 640px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.78fr);
    align-items: stretch;
    gap: 40px;
  }

  .page-about .about-hero__visual {
    min-height: 320px;
    max-height: none;
    aspect-ratio: auto;
  }

  .page-about .about-ver__list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0 28px;
  }

  .page-about .about-route {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 28px;
  }

  .page-about .about-route__item {
    padding-bottom: 0;
    border-bottom: 0;
  }
}

@media (min-width: 940px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    gap: 0 48px;
  }

  .page-about .about-chronicle {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: 0 var(--ab-gap);
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--hdr-h) + 28px);
    align-self: start;
    padding-top: 4px;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    gap: 0;
    padding: 0;
    overflow: visible;
    border-left: 1px solid var(--line-violet);
  }

  .page-about .about-rail__link {
    position: relative;
    flex-direction: row;
    align-items: baseline;
    gap: 10px;
    padding: 9px 0 9px 22px;
    border: 0;
    border-radius: 0;
    white-space: normal;
  }

  .page-about .about-rail__link::before {
    content: "";
    position: absolute;
    left: -3px;
    top: 16px;
    width: 5px;
    height: 5px;
    background: var(--dust);
    transform: rotate(45deg);
    transition: background 0.22s var(--ease), box-shadow 0.22s var(--ease);
  }

  .page-about .about-rail__link:hover::before,
  .page-about .about-rail__link:focus-visible::before {
    background: var(--cyan);
    box-shadow: 0 0 0 4px rgba(43, 227, 198, 0.16);
  }

  .page-about .about-rail__link:hover,
  .page-about .about-rail__link:focus-visible {
    border-color: transparent;
  }

  .page-about .about-rail__year {
    flex: 0 0 58px;
  }

  .page-about .about-flow {
    padding-top: 0;
  }

  .page-about .about-ver__list {
    grid-template-columns: minmax(0, 1fr);
    gap: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}