.page-about {
  --ab-rail: 64px;
  display: block;
  background: var(--white);
  color: var(--ink);
  font-family: var(--font-sans);
}

.page-about *,
.page-about *::before,
.page-about *::after {
  box-sizing: border-box;
}

.page-about .ab-wrap {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 0 var(--gut) 120px;
}

.page-about .breadcrumb {
  padding: 22px 0 18px;
}

/* ---------- 首屏 ---------- */

.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius);
  background: linear-gradient(168deg, var(--navy) 0%, var(--navy-mid) 58%, #0d4f89 100%);
  color: var(--white);
  padding: clamp(40px, 6vw, 84px) clamp(22px, 4.5vw, 64px) clamp(34px, 5vw, 60px);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 5px;
  background: linear-gradient(90deg, var(--blue), var(--mist) 42%, var(--orange) 76%, var(--orange-lt));
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image: repeating-linear-gradient(90deg, rgba(127, 196, 242, 0.14) 0 1px, transparent 1px 52px);
}

.page-about .ab-hero > * {
  position: relative;
  z-index: 1;
}

.page-about .ab-hero-kicker {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin: 0 0 20px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--mist);
}

.page-about .ab-hero-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--neon);
  box-shadow: 0 0 0 4px rgba(76, 227, 154, 0.16);
}

.page-about .ab-hero-title {
  margin: 0 0 24px;
  max-width: 15ch;
  font-size: clamp(32px, 6.2vw, 82px);
  font-weight: 900;
  line-height: 1.06;
  letter-spacing: -0.02em;
}

.page-about .ab-hero-lede {
  margin: 0 0 40px;
  max-width: 56ch;
  font-size: clamp(15px, 1.6vw, 18px);
  line-height: 1.8;
  color: rgba(234, 245, 253, 0.84);
}

.page-about .ab-hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  background: rgba(127, 196, 242, 0.2);
  border-top: 1px solid rgba(127, 196, 242, 0.2);
  border-bottom: 1px solid rgba(127, 196, 242, 0.2);
}

.page-about .ab-hero-stat {
  background: rgba(6, 26, 46, 0.55);
  padding: 18px 16px;
}

.page-about .ab-hero-stat dt {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--mist);
}

.page-about .ab-hero-stat dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(24px, 3.4vw, 36px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  color: var(--orange-lt);
}

/* ---------- 章节骨架 ---------- */

.page-about .ab-sec {
  position: relative;
  padding-top: clamp(46px, 6vw, 86px);
  border-top: 1px solid var(--line);
}

.page-about .ab-hero + .ab-sec {
  margin-top: clamp(46px, 6vw, 86px);
}

.page-about .ab-sec-head {
  display: flex;
  gap: clamp(16px, 3vw, 30px);
  align-items: flex-start;
  margin-bottom: clamp(24px, 3.4vw, 42px);
}

.page-about .ab-sec-num {
  flex: none;
  font-family: var(--font-mono);
  font-size: clamp(26px, 4.2vw, 54px);
  font-weight: 700;
  line-height: 0.92;
  letter-spacing: -0.04em;
  font-variant-numeric: tabular-nums;
  color: var(--blue);
}

.page-about .ab-sec-headtext {
  padding-top: 2px;
}

.page-about .ab-sec-kicker {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--gray);
}

.page-about .ab-sec-title {
  margin: 0;
  font-size: clamp(21px, 2.9vw, 36px);
  font-weight: 800;
  line-height: 1.28;
  letter-spacing: -0.015em;
  color: var(--ink);
}

.page-about .ab-intro {
  max-width: 60ch;
  margin: 0 0 clamp(24px, 3.4vw, 40px);
  font-size: 16px;
  line-height: 1.85;
  color: var(--gray);
}

/* ---------- 双栏 ---------- */

.page-about .ab-cols {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 52px);
}

.page-about .ab-main p {
  max-width: 60ch;
  margin: 0 0 18px;
  font-size: 16px;
  line-height: 1.9;
  color: var(--ink);
}

.page-about .ab-main p:last-child {
  margin-bottom: 0;
}

.page-about .ab-main a {
  color: var(--blue);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
}

.page-about .ab-main a:hover {
  border-bottom-color: var(--orange);
  color: var(--orange);
}

.page-about .ab-side-title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--gray);
}

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

.page-about .ab-side-list li {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
  line-height: 1.6;
  color: var(--gray);
}

.page-about .ab-side-list b {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--blue);
}

.page-about .ab-side-note {
  margin: 14px 0 0;
  font-size: 13px;
  line-height: 1.8;
  color: var(--gray);
}

/* ---------- 媒体框 ---------- */

.page-about .media-frame {
  position: relative;
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--snow);
}

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

.page-about .ab-figure {
  margin-top: clamp(28px, 4vw, 52px);
}

.page-about .ab-figure--wide {
  margin-bottom: clamp(28px, 4vw, 48px);
}

.page-about .media-frame-caption {
  padding: 12px 16px;
  border-top: 1px solid var(--line);
  background: var(--white);
  font-size: 13px;
  line-height: 1.7;
  color: var(--gray);
}

/* ---------- 排班 ---------- */

.page-about .ab-shifts {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: clamp(26px, 4vw, 46px);
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-shift {
  background: var(--white);
  padding: 22px 20px 24px;
}

.page-about .ab-shift-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 12px;
}

.page-about .ab-shift-name {
  margin: 0;
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .ab-shift-tag {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--blue);
  border: 1px solid var(--line);
  padding: 2px 7px;
  border-radius: var(--radius);
}

.page-about .ab-shift p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--gray);
}

/* ---------- 目录字段 ---------- */

.page-about .ab-fields {
  margin: clamp(26px, 4vw, 44px) 0 0;
  border-top: 1px solid var(--line);
}

.page-about .ab-field {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 5px;
  padding: 15px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .ab-field dt {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--blue);
}

.page-about .ab-field dd {
  margin: 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--gray);
}

/* ---------- 时间轴 ---------- */

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

.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 30px;
  bottom: 30px;
  width: 1px;
  background: var(--line);
}

.page-about .ab-node {
  position: relative;
  padding-left: 30px;
  border-bottom: 1px solid var(--line);
}

.page-about .ab-node::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 28px;
  z-index: 1;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--neon);
  box-shadow: 0 0 0 3px rgba(76, 227, 154, 0.16);
}

.page-about .ab-node-btn {
  display: block;
  width: 100%;
  margin: 0;
  padding: 20px 0;
  border: 0;
  background: none;
  text-align: left;
  font: inherit;
  color: inherit;
  cursor: pointer;
}

.page-about .ab-node-ver {
  display: block;
  margin-bottom: 7px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--orange);
}

.page-about .ab-node-title {
  display: block;
  font-size: clamp(17px, 2vw, 22px);
  font-weight: 700;
  line-height: 1.45;
  color: var(--ink);
  transition: color 0.18s ease;
}

.page-about .ab-node-btn:hover .ab-node-title,
.page-about .ab-node-btn:focus-visible .ab-node-title {
  color: var(--blue);
}

.page-about .ab-node-btn:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: 3px;
}

.page-about .ab-node-panel .disclosure-body {
  max-width: 58ch;
  padding: 0 0 22px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--gray);
}

.page-about .ab-node-panel .disclosure-body p {
  margin: 0;
}

/* ---------- 指标条 ---------- */

.page-about .ab-metrics {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1px;
  list-style: none;
  margin: clamp(26px, 4vw, 44px) 0 0;
  padding: 0;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-metrics li {
  background: var(--snow);
  padding: 20px 18px 22px;
}

.page-about .ab-metric-num {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: clamp(26px, 3.6vw, 38px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  color: var(--orange);
}

.page-about .ab-metric-label {
  display: block;
  font-size: 13px;
  line-height: 1.65;
  color: var(--gray);
}

/* ---------- 承诺 ---------- */

.page-about .ab-pledges {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 34px);
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-pledge {
  padding-top: 18px;
  border-top: 2px solid var(--blue);
}

.page-about .ab-pledge-idx {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.2em;
  color: var(--mist);
}

.page-about .ab-pledge-title {
  margin: 0 0 10px;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.45;
  color: var(--ink);
}

.page-about .ab-pledge p {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--gray);
}

.page-about .ab-note {
  max-width: 60ch;
  margin: clamp(24px, 3.4vw, 36px) 0 0;
  padding-left: 14px;
  border-left: 2px solid var(--line);
  font-size: 14px;
  line-height: 1.85;
  color: var(--gray);
}

/* ---------- 结尾行动 ---------- */

.page-about .ab-cta {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  margin-top: clamp(30px, 4vw, 52px);
  padding: clamp(24px, 3.4vw, 38px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(140deg, var(--snow) 0%, var(--white) 62%, rgba(127, 196, 242, 0.16) 100%);
}

.page-about .ab-cta-text {
  margin: 0;
  max-width: 56ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink);
}

.page-about .ab-cta-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
}

/* ---------- 纪年刻度：桌面端 ---------- */

@media (min-width: 900px) {
  .page-about .ab-wrap {
    position: relative;
    padding-left: calc(var(--gut) + var(--ab-rail));
  }

  .page-about .ab-wrap::before {
    content: "";
    position: absolute;
    left: var(--gut);
    top: 150px;
    bottom: 140px;
    width: 1px;
    background: linear-gradient(180deg, transparent, var(--line) 6%, var(--line) 94%, transparent);
  }

  .page-about .ab-sec-head::before {
    content: "";
    position: absolute;
    left: calc(var(--ab-rail) * -1 - 4px);
    top: 14px;
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background: var(--neon);
    box-shadow: 0 0 0 4px rgba(76, 227, 154, 0.14);
  }

  .page-about .ab-cols {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
  }

  .page-about .ab-cols--media {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    align-items: start;
  }

  .page-about .ab-side {
    padding-left: clamp(18px, 2.4vw, 34px);
    border-left: 1px solid var(--line);
  }

  .page-about .ab-shifts {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .ab-pledges {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .ab-cta {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    align-items: center;
  }

  .page-about .ab-field {
    grid-template-columns: 118px minmax(0, 1fr);
    gap: 24px;
    align-items: baseline;
  }
}

@media (min-width: 720px) {
  .page-about .ab-hero-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (max-width: 899px) {
  .page-about .ab-side {
    padding-top: 4px;
  }

  .page-about .ab-timeline::before {
    left: 4px;
  }

  .page-about .ab-node {
    padding-left: 24px;
  }

  .page-about .ab-node::before {
    left: 1px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-node-title {
    transition: none;
  }
}