.page-about {
  --ab-line: rgba(200, 205, 212, 0.2);
  --ab-line-soft: rgba(200, 205, 212, 0.12);
  --ab-card: #12263D;
  --ab-card-deep: rgba(18, 38, 61, 0.68);
  --ab-hover: #1E4A63;
  --ab-cyan: #35E0D0;
  --ab-orange: #FF7A29;
  --ab-batik: #4E7FB8;
  --ab-silver: #C8CDD4;
  --ab-body: rgba(244, 247, 250, 0.8);
  background: #0B1A2B;
  color: #F4F7FA;
  padding-bottom: 0;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  padding: 26px 0 48px;
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(78, 127, 184, 0.16) 1px, transparent 1px),
    linear-gradient(90deg, rgba(78, 127, 184, 0.16) 1px, transparent 1px);
  background-size: 64px 64px;
  -webkit-mask-image: linear-gradient(180deg, #000 0%, rgba(0, 0, 0, 0.15) 82%, transparent 100%);
  mask-image: linear-gradient(180deg, #000 0%, rgba(0, 0, 0, 0.15) 82%, transparent 100%);
  pointer-events: none;
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  top: -28%;
  right: -14%;
  width: min(560px, 78vw);
  aspect-ratio: 1 / 1;
  border-radius: 50%;
  background: radial-gradient(circle at 42% 42%, rgba(53, 224, 208, 0.2), transparent 64%);
  pointer-events: none;
}

.page-about .ab-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .breadcrumb {
  margin-bottom: 22px;
}

.page-about .ab-hero__kicker {
  margin: 0 0 14px;
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--ab-cyan);
}

.page-about .ab-hero__title {
  margin: 0 0 18px;
  max-width: 22ch;
  font-size: clamp(30px, 7.6vw, 54px);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.page-about .ab-hero__lead {
  margin: 0 0 30px;
  max-width: 64ch;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--ab-body);
}

.page-about .ab-hero__stats {
  list-style: none;
  margin: 0;
  padding: 22px 0 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  border-top: 1px solid var(--ab-line);
}

.page-about .ab-stat {
  border: 1px solid var(--ab-line);
  border-left: 2px solid var(--ab-cyan);
  background: var(--ab-card-deep);
  border-radius: 4px;
  padding: 14px 14px 12px;
  transition: background-color 0.2s cubic-bezier(0.4, 0.1, 0.2, 1), border-color 0.2s cubic-bezier(0.4, 0.1, 0.2, 1);
}

.page-about .ab-stat:hover {
  background: var(--ab-hover);
  border-color: rgba(53, 224, 208, 0.42);
}

.page-about .ab-stat__num {
  display: block;
  font-size: 24px;
  line-height: 1.1;
  color: var(--ab-cyan);
  letter-spacing: 0.02em;
}

.page-about .ab-stat__k {
  display: block;
  margin-top: 6px;
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--ab-silver);
}

/* ---------- 主体骨架 ---------- */
.page-about .ab-body {
  display: grid;
  gap: 28px;
  padding-top: 40px;
  padding-bottom: 8px;
}

.page-about .ab-side {
  border: 1px solid var(--ab-line);
  background: rgba(18, 38, 61, 0.6);
  border-radius: 4px;
  padding: 16px 18px 18px;
}

.page-about .ab-side__title {
  margin: 0 0 12px;
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--ab-cyan);
}

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

.page-about .ab-side__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 8px 10px;
  border-left: 2px solid transparent;
  border-radius: 2px;
  font-size: 14px;
  color: var(--ab-silver);
  text-decoration: none;
  transition: color 0.18s cubic-bezier(0.4, 0.1, 0.2, 1),
    background-color 0.18s cubic-bezier(0.4, 0.1, 0.2, 1),
    border-color 0.18s cubic-bezier(0.4, 0.1, 0.2, 1);
}

.page-about .ab-side__link:hover,
.page-about .ab-side__link:focus-visible {
  color: #F4F7FA;
  background: var(--ab-hover);
  border-left-color: var(--ab-cyan);
}

.page-about .ab-side__code {
  flex: 0 0 auto;
  font-size: 11.5px;
  color: var(--ab-cyan);
  letter-spacing: 0.08em;
}

/* ---------- 章节 ---------- */
.page-about .ab-flow {
  min-width: 0;
}

.page-about .ab-sec {
  margin-bottom: 56px;
  scroll-margin-top: 96px;
}

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

.page-about .ab-sec__head {
  display: grid;
  gap: 8px;
  padding-bottom: 14px;
  margin-bottom: 22px;
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-sec__idx {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 11.5px;
  letter-spacing: 0.22em;
  color: var(--ab-cyan);
}

.page-about .ab-sec__idx::after {
  content: "";
  width: 34px;
  height: 1px;
  background: var(--ab-cyan);
  opacity: 0.6;
}

.page-about .ab-sec__title {
  margin: 0;
  font-size: clamp(22px, 5vw, 34px);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.015em;
}

.page-about .ab-sec__lead {
  margin: 0 0 24px;
  max-width: 68ch;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--ab-body);
}

.page-about .ab-sec__lead--after {
  margin: 22px 0 0;
}

.page-about .ab-inline {
  color: var(--ab-cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 224, 208, 0.42);
  transition: border-color 0.18s cubic-bezier(0.4, 0.1, 0.2, 1), color 0.18s cubic-bezier(0.4, 0.1, 0.2, 1);
}

.page-about .ab-inline:hover,
.page-about .ab-inline:focus-visible {
  color: #F4F7FA;
  border-bottom-color: var(--ab-orange);
}

/* ---------- 时间轴 ---------- */
.page-about .ab-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 18px;
  position: relative;
}

.page-about .ab-step {
  position: relative;
  border: 1px solid var(--ab-line);
  border-radius: 4px;
  background: linear-gradient(160deg, rgba(18, 38, 61, 0.92), rgba(11, 26, 43, 0.7));
  padding: 20px 18px 18px;
  overflow: hidden;
  transition: border-color 0.22s cubic-bezier(0.4, 0.1, 0.2, 1), transform 0.22s cubic-bezier(0.4, 0.1, 0.2, 1);
}

.page-about .ab-step::before {
  content: "";
  position: absolute;
  left: 0;
  top: 20px;
  bottom: 20px;
  width: 2px;
  background: var(--ab-cyan);
  opacity: 0.45;
  transform: scaleY(0.32);
  transform-origin: top center;
  transition: transform 0.32s cubic-bezier(0.4, 0.1, 0.2, 1), opacity 0.32s cubic-bezier(0.4, 0.1, 0.2, 1);
}

.page-about .ab-step:hover,
.page-about .ab-step:focus-within {
  border-color: rgba(53, 224, 208, 0.45);
  transform: translateY(-2px);
}

.page-about .ab-step:hover::before,
.page-about .ab-step:focus-within::before {
  transform: scaleY(1);
  opacity: 1;
}

.page-about .ab-step__year {
  display: block;
  margin-bottom: 10px;
  font-size: clamp(34px, 11vw, 54px);
  font-weight: 300;
  line-height: 1;
  letter-spacing: 0.02em;
  color: rgba(53, 224, 208, 0.88);
}

.page-about .ab-step__eyebrow {
  margin: 0 0 8px;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--ab-orange);
}

.page-about .ab-step__title {
  margin: 0 0 10px;
  font-size: 19px;
  font-weight: 700;
  line-height: 1.38;
  letter-spacing: -0.01em;
}

.page-about .ab-step__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.82;
  color: var(--ab-body);
}

.page-about .ab-step__more {
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px dashed var(--ab-line);
  display: grid;
  gap: 7px;
}

.page-about .ab-step__mrow {
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--ab-silver);
}

.page-about .ab-step__mk {
  flex: 0 0 auto;
  min-width: 62px;
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--ab-cyan);
}

/* ---------- 资料库规模 ---------- */
.page-about .ab-metrics {
  list-style: none;
  margin: 0 0 22px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 10px;
}

.page-about .ab-metric {
  border: 1px solid var(--ab-line-soft);
  border-radius: 4px;
  background: rgba(18, 38, 61, 0.5);
  padding: 14px 16px;
}

.page-about .ab-metric__n {
  display: block;
  font-size: 22px;
  line-height: 1.15;
  color: #F4F7FA;
  letter-spacing: 0.02em;
}

.page-about .ab-metric__k {
  display: block;
  margin-top: 5px;
  font-size: 12.5px;
  color: var(--ab-silver);
}

.page-about .ab-db {
  display: grid;
  gap: 20px;
}

.page-about .ab-db__panel {
  border: 1px solid var(--ab-line);
  border-radius: 4px;
  background: rgba(18, 38, 61, 0.55);
  padding: 18px 16px;
}

.page-about .ab-letters {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 8px;
}

.page-about .ab-letter {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 11px 13px;
  border: 1px solid var(--ab-line-soft);
  border-radius: 3px;
  background: rgba(11, 26, 43, 0.6);
  transition: background-color 0.2s cubic-bezier(0.4, 0.1, 0.2, 1), border-color 0.2s cubic-bezier(0.4, 0.1, 0.2, 1);
}

.page-about .ab-letter:hover {
  background: var(--ab-hover);
  border-color: rgba(53, 224, 208, 0.4);
}

.page-about .ab-letter__k {
  font-size: 20px;
  line-height: 1;
  color: var(--ab-cyan);
}

.page-about .ab-letter__v {
  font-size: 13.5px;
  color: #F4F7FA;
}

.page-about .ab-db__note {
  margin: 16px 0 0;
  font-size: 13.5px;
  line-height: 1.78;
  color: var(--ab-silver);
}

.page-about .ab-db__media {
  margin: 0;
}

/* ---------- 成本四项 ---------- */
.page-about .ab-costs {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .ab-cost {
  border: 1px solid var(--ab-line);
  border-radius: 4px;
  background: rgba(18, 38, 61, 0.52);
  padding: 18px 16px 16px;
  transition: background-color 0.22s cubic-bezier(0.4, 0.1, 0.2, 1), border-color 0.22s cubic-bezier(0.4, 0.1, 0.2, 1);
}

.page-about .ab-cost:hover {
  background: var(--ab-hover);
  border-color: rgba(53, 224, 208, 0.38);
}

.page-about .ab-cost__bar {
  display: block;
  height: 5px;
  width: 100%;
  border-radius: 3px;
  margin-bottom: 14px;
}

.page-about .ab-cost__bar--1 { background: #35E0D0; }
.page-about .ab-cost__bar--2 { background: #FF7A29; }
.page-about .ab-cost__bar--3 { background: #4E7FB8; }
.page-about .ab-cost__bar--4 { background: #C8CDD4; }

.page-about .ab-cost__no {
  margin: 0 0 6px;
  font-size: 11.5px;
  letter-spacing: 0.2em;
  color: var(--ab-silver);
}

.page-about .ab-cost__title {
  margin: 0 0 9px;
  font-size: 18px;
  font-weight: 700;
  line-height: 1.35;
}

.page-about .ab-cost__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ab-body);
}

.page-about .ab-cost__more {
  margin: 12px 0 0;
  padding-top: 10px;
  border-top: 1px dashed var(--ab-line);
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--ab-silver);
}

/* ---------- 团队 ---------- */
.page-about .ab-team {
  display: grid;
  gap: 22px;
}

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

.page-about .ab-team__item {
  display: grid;
  grid-template-columns: 54px minmax(0, 1fr);
  gap: 14px;
  align-items: stretch;
  padding: 14px 16px;
  border: 1px solid var(--ab-line);
  border-radius: 4px;
  background: rgba(18, 38, 61, 0.5);
  transition: border-color 0.2s cubic-bezier(0.4, 0.1, 0.2, 1);
}

.page-about .ab-team__item:hover {
  border-color: rgba(255, 122, 41, 0.45);
}

.page-about .ab-team__num {
  font-size: 22px;
  line-height: 1;
  color: var(--ab-orange);
  padding-right: 12px;
  border-right: 1px solid var(--ab-line);
  display: flex;
  align-items: flex-start;
  justify-content: flex-start;
  padding-top: 2px;
}

.page-about .ab-team__name {
  margin: 0 0 5px;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.4;
}

.page-about .ab-team__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
  color: var(--ab-body);
}

.page-about .ab-team__media {
  margin: 0;
}

/* ---------- 覆盖范围 ---------- */
.page-about .ab-coverage {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 10px;
}

.page-about .ab-coverage__item {
  border: 1px solid var(--ab-line-soft);
  border-top: 2px solid var(--ab-batik);
  border-radius: 3px;
  background: rgba(18, 38, 61, 0.45);
  padding: 14px 14px 12px;
  transition: border-top-color 0.2s cubic-bezier(0.4, 0.1, 0.2, 1);
}

.page-about .ab-coverage__item:hover {
  border-top-color: var(--ab-cyan);
}

.page-about .ab-coverage__n {
  display: block;
  font-size: 22px;
  line-height: 1.15;
  color: var(--ab-cyan);
  letter-spacing: 0.02em;
}

.page-about .ab-coverage__k {
  display: block;
  margin-top: 6px;
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--ab-silver);
}

/* ---------- 纠错 ---------- */
.page-about .ab-fix {
  display: grid;
  gap: 12px;
}

.page-about .ab-fix__card {
  position: relative;
  border: 1px solid var(--ab-line);
  border-radius: 4px;
  background: rgba(18, 38, 61, 0.55);
  padding: 18px 16px;
  transition: background-color 0.2s cubic-bezier(0.4, 0.1, 0.2, 1), border-color 0.2s cubic-bezier(0.4, 0.1, 0.2, 1);
}

.page-about .ab-fix__card:hover {
  background: var(--ab-hover);
  border-color: rgba(53, 224, 208, 0.38);
}

.page-about .ab-fix__k {
  margin: 0 0 10px;
  font-size: 11.5px;
  letter-spacing: 0.2em;
  color: var(--ab-silver);
}

.page-about .ab-fix__n {
  margin: 0 0 10px;
  font-size: 34px;
  line-height: 1;
  font-weight: 300;
  color: var(--ab-orange);
  letter-spacing: 0.02em;
}

.page-about .ab-fix__n span {
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--ab-silver);
  margin-left: 4px;
}

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

/* ---------- 底部行动区 ---------- */
.page-about .ab-cta {
  margin-top: 64px;
  padding: 40px 0 44px;
  background: linear-gradient(140deg, rgba(30, 74, 99, 0.92), rgba(11, 26, 43, 0.96));
  border-top: 1px solid rgba(53, 224, 208, 0.35);
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-cta__inner {
  display: grid;
  gap: 18px;
}

.page-about .ab-cta__text {
  margin: 0;
  max-width: 58ch;
  font-size: 16px;
  line-height: 1.8;
  color: #F4F7FA;
}

.page-about .ab-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 图片 ---------- */
.page-about .media__frame {
  overflow: hidden;
  border: 1px solid var(--ab-line);
  border-radius: 4px;
  background: rgba(18, 38, 61, 0.6);
}

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

.page-about .media__caption {
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.65;
  color: var(--ab-silver);
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .ab-hero {
    padding: 34px 0 58px;
  }

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

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

@media (min-width: 768px) {
  .page-about .ab-timeline {
    padding-left: 34px;
    border-left: 1px solid var(--ab-line);
  }

  .page-about .ab-step {
    padding: 22px 22px 20px;
  }

  .page-about .ab-step::after {
    content: "";
    position: absolute;
    left: -40px;
    top: 34px;
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background: var(--ab-cyan);
    box-shadow: 0 0 0 4px rgba(53, 224, 208, 0.14);
  }
}

@media (min-width: 900px) {
  .page-about .ab-db {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: 28px;
    align-items: start;
  }

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

  .page-about .ab-team {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.78fr);
    gap: 28px;
    align-items: start;
  }
}

@media (min-width: 1024px) {
  .page-about .ab-body {
    grid-template-columns: 220px minmax(0, 1fr);
    gap: 56px;
    align-items: start;
    padding-top: 52px;
  }

  .page-about .ab-side {
    position: sticky;
    top: 96px;
  }

  .page-about .ab-sec {
    margin-bottom: 72px;
  }

  .page-about .ab-hero {
    padding: 44px 0 68px;
  }

  .page-about .ab-cta {
    margin-top: 80px;
    padding: 52px 0 56px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-step,
  .page-about .ab-step::before,
  .page-about .ab-cost,
  .page-about .ab-letter,
  .page-about .ab-side__link,
  .page-about .ab-inline {
    transition: none !important;
    transform: none !important;
  }
}