.page-about {
  --ab-rail: 92px;
  background: var(--paper);
  color: var(--graphite);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  padding: 26px 0 38px;
  border-bottom: 1px solid var(--line);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(78deg, rgba(11, 59, 92, .05) 0 1px, transparent 1px 26px);
  pointer-events: none;
}

.page-about .ab-hero__inner {
  position: relative;
}

.page-about .ab-hero__eyebrow {
  margin: 22px 0 12px;
  color: var(--sea);
  letter-spacing: .16em;
}

.page-about .ab-hero__title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(28px, 6.2vw, 52px);
  line-height: 1.14;
  letter-spacing: -.01em;
  color: var(--sea);
  margin: 0 0 16px;
  max-width: 15em;
}

.page-about .ab-hero__lead {
  margin: 0 0 28px;
  font-size: clamp(15px, 2.6vw, 17px);
  line-height: 1.78;
  max-width: 38em;
}

.page-about .ab-hero__stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  box-shadow: var(--shadow-1);
}

.page-about .ab-hero__stats li {
  background: var(--white);
  padding: 14px 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 5px;
  min-width: 0;
}

.page-about .ab-hero__num {
  font-size: 24px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--sea);
  letter-spacing: .01em;
}

.page-about .ab-hero__label {
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--muted);
  letter-spacing: .02em;
}

/* ---------- 章节骨架与左侧编号轨道 ---------- */
.page-about .ab-chapter {
  padding: 34px 0;
  border-top: 1px solid var(--line);
}

.page-about .ab-chapter--last {
  padding-bottom: 56px;
}

.page-about .ab-chapter__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .ab-chapter__rail {
  display: flex;
  align-items: center;
  gap: 10px;
}

.page-about .ab-chapter__dot {
  width: 10px;
  height: 10px;
  flex: none;
  background: var(--orange);
}

.page-about .ab-chapter__num {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .18em;
  color: var(--sea);
}

.page-about .ab-chapter__title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(22px, 4.6vw, 34px);
  line-height: 1.2;
  letter-spacing: -.01em;
  color: var(--sea);
  margin: 0 0 14px;
}

.page-about .ab-chapter__lead {
  margin: 0 0 22px;
  font-size: 16px;
  line-height: 1.78;
  max-width: 40em;
}

.page-about .ab-chapter__tail {
  margin: 20px 0 0;
  font-size: 15.5px;
  line-height: 1.78;
  max-width: 42em;
  padding-left: 14px;
  border-left: 2px solid var(--orange);
}

.page-about .ab-chapter__tail a,
.page-about .ab-path__item a,
.page-about .ab-metrics__foot a {
  color: var(--teal-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .ab-chapter__tail a:hover,
.page-about .ab-path__item a:hover,
.page-about .ab-metrics__foot a:hover {
  color: var(--orange-press);
}

/* ---------- 图片 ---------- */
.page-about .ab-figure {
  margin: 0 0 24px;
}

.page-about .ab-figure--flush {
  margin-bottom: 0;
}

.page-about .ab-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 职能卡片 ---------- */
.page-about .ab-roles {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .ab-role {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 4px;
  box-shadow: var(--shadow-1);
  transition: border-color .24s var(--ease), box-shadow .24s var(--ease);
}

.page-about .ab-role[open] {
  border-color: var(--sea);
  box-shadow: var(--shadow-2);
}

.page-about .ab-role__summary {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 44px 16px 18px;
  cursor: pointer;
  list-style: none;
}

.page-about .ab-role__summary::-webkit-details-marker {
  display: none;
}

.page-about .ab-role__summary::after {
  content: "+";
  position: absolute;
  top: 14px;
  right: 16px;
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--orange-press);
}

.page-about .ab-role[open] .ab-role__summary::after {
  content: "–";
}

.page-about .ab-role__tag {
  font-size: 10.5px;
  letter-spacing: .18em;
  color: var(--orange-press);
}

.page-about .ab-role__name {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 19px;
  line-height: 1.3;
  color: var(--sea);
}

.page-about .ab-role__more {
  font-size: 12.5px;
  color: var(--muted);
}

.page-about .ab-role__text {
  margin: 0;
  padding: 14px 18px 18px;
  border-top: 1px solid var(--line);
  font-size: 15px;
  line-height: 1.78;
}

/* ---------- 一天的时间表 ---------- */
.page-about .ab-day {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-day__item {
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  gap: 14px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

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

.page-about .ab-day__time {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .06em;
  color: var(--orange-press);
  padding-top: 3px;
}

.page-about .ab-day__body h3 {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 16.5px;
  line-height: 1.4;
  color: var(--sea);
}

.page-about .ab-day__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
}

/* ---------- 服务网络 ---------- */
.page-about .ab-net {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  margin-bottom: 8px;
}

.page-about .ab-net__field {
  position: relative;
  height: 190px;
  border: 1px solid var(--line);
  background-color: var(--mist);
  background-image: radial-gradient(rgba(27, 127, 120, .5) 1.6px, transparent 1.7px);
  background-size: 18px 18px;
}

.page-about .ab-net__hub {
  position: absolute;
  width: 9px;
  height: 9px;
  background: var(--orange);
  box-shadow: 0 0 0 4px rgba(255, 107, 53, .18);
}

.page-about .ab-net__hub--a { top: 18%; left: 24%; }
.page-about .ab-net__hub--b { top: 44%; left: 52%; }
.page-about .ab-net__hub--c { top: 68%; left: 30%; }
.page-about .ab-net__hub--d { top: 30%; left: 76%; }

.page-about .ab-net__note {
  margin: 10px 0 0;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--muted);
}

.page-about .ab-net__facts {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-net__facts li {
  background: var(--white);
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 13px 16px;
  font-size: 14.5px;
  line-height: 1.6;
}

.page-about .ab-net__num {
  font-size: 20px;
  font-weight: 700;
  color: var(--teal-deep);
  letter-spacing: .02em;
}

/* ---------- 指标深色区 ---------- */
.page-about .ab-metrics {
  position: relative;
  overflow: hidden;
  background: var(--ink);
  color: var(--white);
  padding: 40px 0;
}

.page-about .ab-metrics::before {
  content: "";
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(78deg, rgba(46, 196, 182, .13) 0 1px, transparent 1px 42px);
  pointer-events: none;
}

.page-about .ab-metrics .container {
  position: relative;
}

.page-about .ab-metrics__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 22px;
}

.page-about .ab-metrics__num {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .18em;
  color: var(--teal);
}

.page-about .ab-metrics__head h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(21px, 4.4vw, 32px);
  line-height: 1.22;
  letter-spacing: -.01em;
  color: var(--white);
}

.page-about .ab-metrics__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .ab-metric {
  background: rgba(255, 255, 255, .045);
  border: 1px solid rgba(255, 255, 255, .16);
  border-top: 2px solid var(--teal);
  padding: 20px 18px;
}

.page-about .ab-metric__value {
  display: block;
  font-size: clamp(30px, 7.4vw, 44px);
  font-weight: 700;
  line-height: 1;
  color: var(--white);
  letter-spacing: .01em;
}

.page-about .ab-metric__unit {
  font-size: .42em;
  margin-left: 5px;
  letter-spacing: .06em;
  color: var(--teal);
}

.page-about .ab-metric__label {
  display: block;
  margin-top: 12px;
  font-size: 14.5px;
  line-height: 1.75;
  color: rgba(255, 255, 255, .8);
}

.page-about .ab-metrics__foot {
  margin: 22px 0 0;
  padding-top: 16px;
  border-top: 1px solid rgba(255, 255, 255, .16);
  font-size: 14px;
  line-height: 1.75;
  color: rgba(255, 255, 255, .74);
}

.page-about .ab-metrics__foot a {
  color: var(--teal);
}

.page-about .ab-metrics__foot a:hover {
  color: var(--white);
}

/* ---------- 迭代路径 ---------- */
.page-about .ab-path {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-path__item {
  position: relative;
  padding: 0 0 20px 26px;
  border-left: 1px solid var(--line);
}

.page-about .ab-path__item:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.page-about .ab-path__item::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 5px;
  width: 9px;
  height: 9px;
  background: var(--orange);
}

.page-about .ab-path__tag {
  display: block;
  font-size: 10.5px;
  letter-spacing: .18em;
  color: var(--teal-deep);
  margin-bottom: 5px;
}

.page-about .ab-path__item h3 {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 17px;
  line-height: 1.35;
  color: var(--sea);
}

.page-about .ab-path__item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
}

/* ---------- 合作入口 ---------- */
.page-about .ab-coop {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}

.page-about .ab-coop__card {
  display: flex;
  flex-direction: column;
  gap: 12px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 4px;
  box-shadow: var(--shadow-1);
  padding: 22px 20px;
  transition: box-shadow .24s var(--ease), transform .24s var(--ease);
}

.page-about .ab-coop__card:hover {
  box-shadow: var(--shadow-2);
  transform: translateY(-2px);
}

.page-about .ab-coop__tag {
  font-size: 10.5px;
  letter-spacing: .18em;
  color: var(--orange-press);
}

.page-about .ab-coop__card h3 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 20px;
  line-height: 1.3;
  color: var(--sea);
}

.page-about .ab-coop__card p {
  margin: 0;
  flex: 1;
  font-size: 15px;
  line-height: 1.78;
}

.page-about .ab-coop__card .btn {
  align-self: flex-start;
}

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

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

  .page-about .ab-net__facts li {
    flex-direction: column;
    gap: 4px;
    padding: 16px;
  }

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

@media (min-width: 760px) {
  .page-about .ab-hero {
    padding: 34px 0 46px;
  }

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

  .page-about .ab-hero__num {
    font-size: 30px;
  }
}

@media (min-width: 900px) {
  .page-about .ab-chapter {
    padding: 54px 0;
  }

  .page-about .ab-chapter__inner {
    position: relative;
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: 32px;
  }

  .page-about .ab-chapter__inner::before {
    content: "";
    position: absolute;
    left: 4.5px;
    top: 0;
    bottom: 0;
    width: 1px;
    background: var(--line);
  }

  .page-about .ab-chapter__rail {
    position: relative;
    z-index: 1;
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
    padding-top: 5px;
  }

  .page-about .ab-chapter__dot {
    background: var(--orange);
  }

  .page-about .ab-chapter__lead {
    max-width: 36em;
  }

  .page-about .ab-net {
    grid-template-columns: 1.02fr .98fr;
    gap: 28px;
    align-items: start;
  }

  .page-about .ab-net__field {
    height: 230px;
  }

  .page-about .ab-coop {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
  }

  .page-about .ab-metrics {
    padding: 56px 0;
  }

  .page-about .ab-day__item {
    grid-template-columns: 76px minmax(0, 1fr);
    gap: 20px;
  }
}

@media (min-width: 1180px) {
  .page-about .ab-chapter:nth-of-type(even) .ab-chapter__body {
    margin-left: 26px;
  }

  .page-about .ab-path__item {
    padding-left: 30px;
    padding-bottom: 24px;
  }

  .page-about .ab-role__summary {
    padding: 20px 46px 18px 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-role,
  .page-about .ab-coop__card {
    transition: none;
  }

  .page-about .ab-coop__card:hover {
    transform: none;
  }
}