.page-about {
  --ab-line: rgba(95, 119, 137, 0.32);
  --ab-line-strong: rgba(95, 119, 137, 0.55);
  --ab-grid: rgba(95, 119, 137, 0.16);
  background: var(--ink-900);
  color: var(--paper);
  font-family: var(--sans);
  overflow-x: hidden;
}

.page-about .ab-crumbs-wrap {
  padding: 18px 0 0;
}

.page-about .ab-crumbs .crumbs__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--mist);
  text-transform: uppercase;
}

.page-about .ab-crumbs__link {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .ab-crumbs__link:hover,
.page-about .ab-crumbs__link:focus-visible {
  color: var(--green);
  border-bottom-color: var(--green);
}

.page-about .ab-crumbs .crumbs__current {
  color: var(--paper);
}

.page-about .ab-eyebrow {
  margin: 0;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--green);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  padding: 26px 0 46px;
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--ab-grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--ab-grid) 1px, transparent 1px);
  background-size: 96px 96px;
  -webkit-mask-image: linear-gradient(180deg, #000 0%, rgba(0, 0, 0, 0.2) 70%, transparent 100%);
  mask-image: linear-gradient(180deg, #000 0%, rgba(0, 0, 0, 0.2) 70%, transparent 100%);
  pointer-events: none;
}

.page-about .ab-hero__grid {
  position: relative;
  display: grid;
  gap: 30px;
  align-items: end;
}

.page-about .ab-hero__title {
  margin: 14px 0 16px;
  font-size: clamp(30px, 7vw, 58px);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: -0.03em;
  color: var(--paper);
  max-width: 15em;
}

.page-about .ab-hero__lead {
  margin: 0;
  max-width: 34em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .ab-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  margin: 26px 0 0;
  padding: 18px 0 0;
  list-style: none;
  border-top: 1px solid var(--ab-line-strong);
}

.page-about .ab-stats__item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 0;
}

.page-about .ab-stats__num {
  font-size: clamp(18px, 3vw, 24px);
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--green);
}

.page-about .ab-stats__label {
  font-size: 11px;
  line-height: 1.6;
  color: var(--mist);
}

.page-about .ab-hero__actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  margin-top: 26px;
}

.page-about .ab-hero__ghost {
  color: var(--paper);
}

.page-about .ab-hero__frame {
  position: relative;
  border: 1px solid var(--ab-line-strong);
  overflow: hidden;
}

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

.page-about .ab-hero__frame .frame__tag {
  position: absolute;
  left: 12px;
  bottom: 12px;
  padding: 4px 8px;
  font-size: 10px;
  letter-spacing: 0.12em;
  color: var(--green);
  background: rgba(6, 23, 37, 0.78);
  border: 1px solid var(--ab-line-strong);
}

/* ---------- 通用章节 ---------- */
.page-about .ab-sec {
  padding: 48px 0;
}

.page-about .ab-head {
  max-width: 40em;
  margin-bottom: 26px;
}

.page-about .ab-head h2 {
  margin: 12px 0 10px;
  font-size: clamp(23px, 4vw, 34px);
  font-weight: 900;
  line-height: 1.25;
  letter-spacing: -0.02em;
  color: var(--paper);
}

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

.page-about .ab-text {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--mist);
}

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

/* ---------- 问题叙事 ---------- */
.page-about .ab-problem__grid {
  display: grid;
  gap: 24px;
}

.page-about .ab-problem__panel {
  position: relative;
  padding: 28px 22px 26px;
  background: var(--oldpaper);
  color: var(--ink-900);
  border-left: 5px solid var(--orange);
}

.page-about .ab-problem__num {
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: 0.2em;
  color: #8a5a2a;
}

.page-about .ab-problem__panel h2 {
  margin: 0 0 14px;
  font-size: clamp(21px, 3.6vw, 28px);
  font-weight: 900;
  line-height: 1.3;
  letter-spacing: -0.02em;
  color: var(--ink-900);
}

.page-about .ab-problem__panel .ab-text {
  color: #33291c;
}

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

.page-about .ab-problem__item {
  display: flex;
  gap: 14px;
  padding: 16px 0;
  border-bottom: 1px solid var(--ab-line);
  font-size: 14px;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .ab-problem__index {
  flex: none;
  width: 22px;
  height: 22px;
  display: grid;
  place-items: center;
  font-size: 11px;
  color: var(--orange);
  border: 1px solid var(--ab-line-strong);
}

/* ---------- 时间线 ---------- */
.page-about .ab-timeline__grid {
  display: grid;
  gap: 20px;
}

.page-about .ab-scale__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-scale__link {
  display: inline-block;
  padding: 5px 10px;
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--mist);
  text-decoration: none;
  border: 1px solid var(--ab-line);
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .ab-scale__link:hover,
.page-about .ab-scale__link:focus-visible {
  color: var(--ink-900);
  background: var(--green);
  border-color: var(--green);
}

.page-about .ab-stage {
  border: 1px solid var(--ab-line);
  background: var(--ink-800);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 14px), calc(100% - 14px) 100%, 0 100%);
}

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

.page-about .ab-stage__sum {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .ab-stage__sum::after {
  content: "+";
  margin-left: auto;
  font-family: var(--mono);
  font-size: 15px;
  color: var(--green);
}

.page-about .ab-stage[open] .ab-stage__sum::after {
  content: "–";
  color: var(--orange);
}

.page-about .ab-stage__year {
  flex: none;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--orange);
}

.page-about .ab-stage__name {
  font-size: 15px;
  font-weight: 700;
  line-height: 1.55;
  color: var(--paper);
}

.page-about .ab-stage__body {
  padding: 14px 18px 20px;
  border-top: 1px solid var(--ab-line);
}

.page-about .ab-stage__body .ab-text {
  font-size: 14px;
}

/* ---------- 数据刻度带 ---------- */
.page-about .ab-band {
  background: var(--ink-800);
  border-top: 1px solid var(--ab-line-strong);
  border-bottom: 1px solid var(--ab-line-strong);
}

.page-about .ab-band__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.page-about .ab-band__item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 22px 16px;
  border-top: 1px solid var(--ab-line);
}

.page-about .ab-band__item:nth-child(odd) {
  border-right: 1px solid var(--ab-line);
}

.page-about .ab-band__num {
  font-size: clamp(24px, 5vw, 34px);
  font-weight: 700;
  letter-spacing: 0.03em;
  color: var(--paper);
}

.page-about .ab-band__item:nth-child(3) .ab-band__num {
  color: var(--green);
}

.page-about .ab-band__unit {
  margin-left: 3px;
  font-size: 12px;
  color: var(--mist);
}

.page-about .ab-band__label {
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

/* ---------- 方法论 ---------- */
.page-about .ab-method__grid {
  display: grid;
  gap: 28px;
}

.page-about .ab-tree {
  display: block;
  width: 100%;
  max-width: 360px;
  height: auto;
  margin-bottom: 8px;
}

.page-about .ab-tree__line {
  stroke: var(--green);
  opacity: 0.7;
}

.page-about .ab-tree__dot {
  fill: var(--ink-900);
  stroke: var(--green);
  stroke-width: 1.5;
}

.page-about .ab-tree__dot--on {
  fill: var(--green);
}

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

.page-about .ab-step {
  display: flex;
  gap: 14px;
  padding: 14px 14px 14px 0;
  border-top: 1px solid var(--ab-line);
  transition: transform 220ms var(--ease), background-color 220ms var(--ease);
}

.page-about .ab-step:hover {
  transform: translateX(4px);
  background: var(--ink-800);
}

.page-about .ab-step__num {
  flex: none;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--green);
  padding-top: 3px;
}

.page-about .ab-step__title {
  margin: 0 0 4px;
  font-size: 16px;
  font-weight: 700;
  color: var(--paper);
}

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

.page-about .ab-method__frame {
  border: 1px solid var(--ab-line);
  position: relative;
  overflow: hidden;
}

.page-about .ab-method__frame img {
  display: block;
  width: 100%;
  height: 100%;
  max-height: 420px;
  object-fit: cover;
}

.page-about .ab-method__frame .frame__tag {
  position: absolute;
  right: 12px;
  top: 12px;
  padding: 4px 8px;
  font-size: 10px;
  letter-spacing: 0.12em;
  color: var(--orange);
  background: rgba(6, 23, 37, 0.8);
  border: 1px solid var(--ab-line-strong);
}

/* ---------- 团队 ---------- */
.page-about .ab-team__grid {
  display: grid;
  gap: 28px;
}

.page-about .ab-team h2 {
  margin: 12px 0 14px;
  font-size: clamp(23px, 4vw, 34px);
  font-weight: 900;
  line-height: 1.25;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .ab-roles {
  display: grid;
  gap: 0;
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--ab-line-strong);
}

.page-about .ab-roles__item {
  display: flex;
  align-items: baseline;
  gap: 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-roles__n {
  flex: none;
  min-width: 44px;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--green);
}

.page-about .ab-roles__text {
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist);
}

.page-about .ab-note {
  margin: 16px 0 0;
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--silver);
}

.page-about .ab-team__frame {
  border: 1px solid var(--ab-line);
  position: relative;
  overflow: hidden;
}

.page-about .ab-team__frame img {
  display: block;
  width: 100%;
  height: 100%;
  max-height: 460px;
  object-fit: cover;
}

.page-about .ab-team__frame .frame__tag {
  position: absolute;
  left: 12px;
  bottom: 12px;
  padding: 4px 8px;
  font-size: 10px;
  letter-spacing: 0.12em;
  color: var(--green);
  background: rgba(6, 23, 37, 0.8);
  border: 1px solid var(--ab-line-strong);
}

/* ---------- 合作生态 ---------- */
.page-about .ab-eco__grid {
  display: grid;
  gap: 16px;
}

.page-about .ab-eco__card {
  padding: 22px 20px;
  background: var(--ink-700);
  border-left: 2px solid var(--green);
}

.page-about .ab-eco__n {
  display: block;
  font-size: 28px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--orange);
  line-height: 1;
}

.page-about .ab-eco__title {
  margin: 10px 0 10px;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.5;
  color: var(--paper);
}

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

.page-about .ab-eco__link {
  display: inline-block;
  margin-top: 14px;
  padding-bottom: 2px;
  font-size: 13px;
  font-weight: 700;
  color: var(--green);
  text-decoration: none;
  border-bottom: 1px solid var(--green);
}

.page-about .ab-eco__link:hover,
.page-about .ab-eco__link:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--paper);
}

/* ---------- 合规 ---------- */
.page-about .ab-trust__panel {
  padding: 26px 22px;
  background: var(--ink-800);
  border: 1px solid var(--ab-line-strong);
  clip-path: polygon(0 0, calc(100% - 18px) 0, 100% 18px, 100% 100%, 0 100%);
}

.page-about .ab-trust__panel h2 {
  margin: 12px 0 14px;
  font-size: clamp(21px, 3.6vw, 28px);
  font-weight: 900;
  line-height: 1.3;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .ab-trust__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

/* ---------- 继续了解 ---------- */
.page-about .ab-more__grid {
  display: grid;
  gap: 12px;
}

.page-about .ab-more__link {
  position: relative;
  display: grid;
  gap: 4px;
  padding: 18px 44px 18px 18px;
  background: var(--ink-800);
  border: 1px solid var(--ab-line);
  text-decoration: none;
  transition: background-color 200ms var(--ease), border-color 200ms var(--ease), transform 200ms var(--ease);
}

.page-about .ab-more__link:hover,
.page-about .ab-more__link:focus-visible {
  background: var(--ink-700);
  border-color: var(--green);
  transform: translateX(3px);
}

.page-about .ab-more__title {
  font-size: 16px;
  font-weight: 700;
  color: var(--paper);
}

.page-about .ab-more__desc {
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .ab-more__arrow {
  position: absolute;
  right: 16px;
  bottom: 16px;
  font-family: var(--mono);
  font-size: 16px;
  color: var(--green);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .ab-sec {
    padding: 60px 0;
  }

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

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

  .page-about .ab-band__item:first-child {
    border-left: 0;
  }

  .page-about .ab-band__item:nth-child(odd) {
    border-right: 0;
  }

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

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

@media (min-width: 920px) {
  .page-about .ab-hero {
    padding: 36px 0 64px;
  }

  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: 44px;
  }

  .page-about .ab-problem__grid {
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
    gap: 40px;
  }

  .page-about .ab-timeline__grid {
    grid-template-columns: 130px minmax(0, 1fr);
    gap: 40px;
    align-items: start;
  }

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

  .page-about .ab-scale__list {
    flex-direction: column;
    gap: 0;
    border-left: 1px solid var(--ab-line-strong);
  }

  .page-about .ab-scale__link {
    position: relative;
    display: block;
    padding: 9px 0 9px 18px;
    border: 0;
    background: none;
    font-size: 12px;
  }

  .page-about .ab-scale__link::before {
    content: "";
    position: absolute;
    left: -4px;
    top: 50%;
    width: 7px;
    height: 7px;
    margin-top: -3.5px;
    background: var(--ink-900);
    border: 1px solid var(--silver);
    border-radius: 50%;
    transition: background-color 160ms var(--ease), border-color 160ms var(--ease);
  }

  .page-about .ab-scale__link:hover,
  .page-about .ab-scale__link:focus-visible {
    color: var(--green);
    background: none;
  }

  .page-about .ab-scale__link:hover::before,
  .page-about .ab-scale__link:focus-visible::before {
    background: var(--green);
    border-color: var(--green);
  }

  .page-about .ab-stage:nth-child(odd) {
    margin-right: 7%;
  }

  .page-about .ab-stage:nth-child(even) {
    margin-left: 7%;
  }

  .page-about .ab-method__grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .ab-team__grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    gap: 44px;
    align-items: start;
  }

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

  .page-about .ab-trust__panel {
    padding: 34px 32px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-step,
  .page-about .ab-more__link,
  .page-about .ab-crumbs__link,
  .page-about .ab-scale__link {
    transition: none;
  }

  .page-about .ab-step:hover,
  .page-about .ab-more__link:hover {
    transform: none;
  }
}