.page-about {
  --ab-rail: 190px;
  --ab-text: rgba(232, 237, 242, .84);
}

/* ---------- 面包屑与首屏 ---------- */
.page-about .ms-crumb {
  padding-top: 20px;
}

.page-about .ab-hero {
  padding-bottom: 12px;
}

.page-about .ab-hero__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
  padding-top: 26px;
  padding-bottom: 10px;
}

.page-about .ab-hero__eyebrow {
  margin: 0 0 14px;
  font-family: var(--ms-display);
  font-size: 12.5px;
  letter-spacing: .08em;
  color: var(--ms-cyan);
  text-transform: uppercase;
}

.page-about .ab-hero__title {
  margin: 0;
  font-family: var(--ms-display);
  font-weight: 800;
  font-size: clamp(30px, 7.2vw, 46px);
  line-height: 1.16;
  letter-spacing: -.01em;
  color: var(--ms-white);
  max-width: 15em;
}

.page-about .ab-hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 26px;
  margin: 22px 0 0;
  padding: 16px 0 0;
  border-top: 1px solid var(--ms-line-soft);
}

.page-about .ab-hero__metaitem {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .ab-hero__metaitem dt {
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--ms-silver);
}

.page-about .ab-hero__metaitem dd {
  margin: 0;
  font-family: var(--ms-display);
  font-size: 15px;
  letter-spacing: .04em;
  color: var(--ms-white);
}

.page-about .ab-hero__aside {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.page-about .ab-hero__text {
  margin: 0;
  font-size: 16.5px;
  line-height: 1.8;
  color: var(--ab-text);
}

.page-about .ab-hero__text--sub {
  font-size: 15px;
  color: var(--ms-silver);
  padding-left: 16px;
  border-left: 2px solid var(--ms-line-amber);
}

.page-about .ab-hero__figure {
  margin: 10px 0 0;
  border: 1px solid var(--ms-line);
  background:
    linear-gradient(155deg, rgba(45, 212, 200, .10), transparent 45%),
    linear-gradient(320deg, rgba(242, 169, 59, .12), transparent 55%),
    var(--ms-panel);
  box-shadow: var(--ms-shadow);
  overflow: hidden;
}

.page-about .ms-figure__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .ms-figure__cap {
  padding: 10px 14px 12px;
  font-family: var(--ms-serif);
  font-size: 13px;
  line-height: 1.6;
  color: var(--ms-silver);
  border-top: 1px solid var(--ms-line-soft);
}

/* ---------- 时间轴区 ---------- */
.page-about .ab-timeline__head {
  margin-bottom: 26px;
}

.page-about .ab-jump {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 38px;
}

.page-about .ab-jump__link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 8px 14px;
  border: 1px solid var(--ms-line-soft);
  border-radius: var(--ms-radius);
  background: rgba(14, 34, 51, .5);
  color: var(--ms-silver);
  font-size: 13.5px;
  text-decoration: none;
  transition: border-color .25s var(--ms-ease), color .25s var(--ms-ease), background-color .25s var(--ms-ease);
}

.page-about .ab-jump__link:hover,
.page-about .ab-jump__link:focus-visible {
  border-color: var(--ms-line-amber);
  background: rgba(242, 169, 59, .08);
  color: var(--ms-white);
}

.page-about .ab-jump__idx {
  font-family: var(--ms-display);
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--ms-amber);
}

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

.page-about .ab-stages::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 10px;
  bottom: 34px;
  width: 1px;
  background: linear-gradient(180deg,
    rgba(143, 232, 224, 0) 0%,
    rgba(143, 232, 224, .18) 8%,
    rgba(143, 232, 224, .18) 88%,
    rgba(143, 232, 224, 0) 100%);
}

.page-about .ab-stage {
  position: relative;
  padding-bottom: 46px;
}

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

.page-about .ab-stage::before {
  content: "";
  position: absolute;
  left: -28px;
  top: 7px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ms-amber);
  box-shadow: 0 0 0 4px rgba(242, 169, 59, .12);
  transition: box-shadow .3s var(--ms-ease), background-color .3s var(--ms-ease);
}

.page-about .ab-stage:hover::before {
  background: var(--ms-cyan);
  box-shadow: 0 0 0 7px rgba(45, 212, 200, .18);
}

.page-about .ab-stage__rail {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 12px;
}

.page-about .ab-stage__num {
  font-family: var(--ms-display);
  font-weight: 800;
  font-size: 30px;
  line-height: 1;
  letter-spacing: .06em;
  color: var(--ms-amber-deep);
  transition: color .3s var(--ms-ease);
}

.page-about .ab-stage:hover .ab-stage__num {
  color: var(--ms-amber);
}

.page-about .ab-stage__title {
  margin: 0 0 14px;
  font-family: var(--ms-serif);
  font-weight: 600;
  font-size: clamp(20px, 4.6vw, 26px);
  line-height: 1.4;
  color: var(--ms-white);
}

.page-about .ab-stage__text {
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ab-text);
}

.page-about .ab-stage__body {
  max-width: 66ch;
}

.page-about .ab-stage__figure {
  margin: 22px 0 20px;
  border: 1px solid var(--ms-line);
  background:
    linear-gradient(200deg, rgba(45, 212, 200, .10), transparent 55%),
    var(--ms-panel);
  box-shadow: var(--ms-shadow);
  overflow: hidden;
}

.page-about .ms-list {
  margin: 18px 0 0;
}

.page-about .ms-list li {
  line-height: 1.75;
}

.page-about .ab-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 22px;
}

/* ---------- 平板与桌面 ---------- */
@media (min-width: 640px) {
  .page-about .ab-hero__inner {
    gap: 30px;
  }
}

@media (min-width: 900px) {
  .page-about .ms-crumb {
    padding-top: 26px;
  }

  .page-about .ab-hero__inner {
    grid-template-columns: minmax(0, 0.86fr) minmax(0, 1.14fr);
    gap: 64px;
    align-items: start;
    padding-top: 38px;
    padding-bottom: 26px;
  }

  .page-about .ab-hero__title {
    font-size: clamp(34px, 3.4vw, 48px);
  }

  .page-about .ab-hero__meta {
    flex-direction: column;
    gap: 14px;
    margin-top: 28px;
  }

  .page-about .ab-hero__text {
    font-size: 17px;
  }

  .page-about .ab-hero__figure {
    margin-top: 14px;
  }

  .page-about .ab-stages {
    padding-left: 56px;
  }

  .page-about .ab-stages::before {
    left: 5px;
  }

  .page-about .ab-stage {
    display: grid;
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: 0 44px;
    padding-bottom: 64px;
  }

  .page-about .ab-stage::before {
    left: -56px;
    top: 9px;
  }

  .page-about .ab-stage__rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    margin-bottom: 0;
    padding-top: 4px;
  }

  .page-about .ab-stage__num {
    font-size: 38px;
  }

  .page-about .ab-stage__title {
    font-size: 26px;
  }

  .page-about .ab-stage__body {
    max-width: 62ch;
  }

  .page-about .ab-stage__figure--wide {
    margin-right: -8%;
  }
}

@media (min-width: 1180px) {
  .page-about .ab-hero__inner {
    gap: 76px;
  }

  .page-about .ab-stage__num {
    font-size: 44px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-jump__link,
  .page-about .ab-stage::before,
  .page-about .ab-stage__num {
    transition: none;
  }
}