.page-about {
  overflow-x: clip;
  background: var(--bg);
  color: var(--text);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  padding: clamp(34px, 6vw, 76px) 0 clamp(48px, 7vw, 104px);
  isolation: isolate;
}

.page-about .ab-hero__glow {
  position: absolute;
  inset: -20% -10% auto -10%;
  height: 130%;
  z-index: -1;
  background:
    linear-gradient(118deg, rgba(21, 87, 255, .26) 0%, rgba(11, 14, 19, 0) 48%),
    linear-gradient(300deg, rgba(43, 245, 216, .12) 0%, rgba(11, 14, 19, 0) 42%),
    repeating-linear-gradient(118deg, rgba(58, 66, 78, .28) 0 1px, rgba(11, 14, 19, 0) 1px 26px);
  pointer-events: none;
}

.page-about .ab-hero__inner {
  display: flex;
  flex-direction: column;
  gap: clamp(16px, 2.4vw, 24px);
  max-width: none;
}

.page-about .ab-hero .eyebrow {
  color: var(--cyan);
  letter-spacing: .18em;
  font-family: var(--font-mono);
  font-size: 13px;
  text-transform: uppercase;
}

.page-about .ab-hero__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(32px, 7.4vw, 76px);
  line-height: 1.06;
  letter-spacing: -.02em;
  max-width: 18ch;
  background: linear-gradient(96deg, var(--paper) 0%, var(--paper) 56%, var(--cyan) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.page-about .ab-hero__lede {
  margin: 0;
  max-width: 62ch;
  font-size: clamp(15px, 1.6vw, 18px);
  line-height: 1.75;
  color: var(--text-dim);
}

.page-about .ab-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(10px, 2vw, 22px);
  background: var(--line);
  border: 1px solid var(--line);
  clip-path: polygon(0 0, calc(100% - var(--cut)) 0, 100% var(--cut), 100% 100%, 0 100%);
}

.page-about .ab-fact {
  display: grid;
  grid-template-columns: auto auto;
  align-items: baseline;
  gap: 0 6px;
  padding: clamp(14px, 2.4vw, 22px) clamp(14px, 2vw, 20px);
  background: var(--rock);
  transition: background .2s var(--ease);
}

.page-about .ab-fact:hover {
  background: #1B2230;
}

.page-about .ab-fact .datum__value {
  font-family: var(--font-mono);
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 700;
  color: var(--cyan);
  letter-spacing: -.01em;
}

.page-about .ab-fact .datum__unit {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--cyan);
  opacity: .75;
}

.page-about .ab-fact .datum__label {
  grid-column: 1 / -1;
  margin-top: 6px;
  font-size: 13px;
  color: var(--text-dim);
  letter-spacing: .06em;
}

/* ---------- 章节基础 ---------- */
.page-about .chapter {
  margin-bottom: clamp(32px, 4.6vw, 60px);
}

.page-about .chapter__num {
  font-family: var(--font-serif);
}

.page-about .chapter__title {
  max-width: 22ch;
}

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

/* ---------- 双栏骨架 ---------- */
.page-about .ab-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4.4vw, 52px);
}

.page-about .ab-split__rail {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.page-about .ab-figure {
  margin: 0;
  width: 100%;
  position: relative;
  overflow: hidden;
}

.page-about .ab-figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  aspect-ratio: 4 / 3;
  filter: saturate(.82) contrast(1.05);
}

.page-about .ab-figure__cap {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--text-dim);
  padding-left: 14px;
  position: relative;
}

.page-about .ab-figure__cap::before {
  content: "";
  position: absolute;
  left: 0;
  top: .72em;
  width: 24px;
  height: 2px;
  background: var(--cyan);
}

/* ---------- 时间线 ---------- */
.page-about .ab-timeline {
  position: relative;
  padding-left: 30px;
}

.page-about .ab-timeline__line {
  position: absolute;
  left: 6px;
  top: 6px;
  bottom: 6px;
  width: 2px;
  height: calc(100% - 12px);
}

.page-about .ab-timeline__line path {
  stroke: var(--line);
  stroke-width: 2;
  fill: none;
}

.page-about .ab-timeline__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: clamp(22px, 3.4vw, 40px);
}

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

.page-about .ab-node::before {
  content: "";
  position: absolute;
  left: -30px;
  top: 7px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--ink);
  border: 2px solid var(--line);
  transition: border-color .24s var(--ease), box-shadow .24s var(--ease), background .24s var(--ease);
}

.page-about .ab-node.is-in::before,
.page-about .ab-node:hover::before,
.page-about .ab-node:focus-within::before {
  border-color: var(--cyan);
  background: var(--cyan);
  box-shadow: 0 0 0 5px rgba(43, 245, 216, .14);
}

.page-about .ab-node__year {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: .08em;
  color: var(--cyan);
  background: rgba(43, 245, 216, .08);
  border: 1px solid rgba(43, 245, 216, .28);
  padding: 3px 10px;
  margin-bottom: 10px;
}

.page-about .ab-node--now .ab-node__year {
  color: var(--ink);
  background: var(--cyan);
  border-color: var(--cyan);
  font-weight: 700;
}

.page-about .ab-node__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(18px, 2.3vw, 24px);
  line-height: 1.32;
  letter-spacing: -.01em;
  color: var(--paper);
}

.page-about .ab-node__text {
  margin: 0;
  max-width: 56ch;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--text-dim);
}

/* ---------- 团队矩阵 ---------- */
.page-about .ab-team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(14px, 2vw, 22px);
}

.page-about .ab-team__panel {
  padding: clamp(20px, 3vw, 28px);
  background: var(--panel);
  transition: transform .24s var(--ease), border-color .24s var(--ease), background .24s var(--ease);
  outline: none;
}

.page-about .ab-team__panel:hover,
.page-about .ab-team__panel:focus-visible {
  transform: translateY(-4px);
  background: #1B2230;
}

.page-about .ab-team__panel:focus-visible {
  box-shadow: 0 0 0 2px var(--cyan);
}

.page-about .ab-team__tag {
  margin: 0 0 12px;
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .14em;
  color: var(--moss);
  border-bottom: 1px solid rgba(110, 143, 90, .5);
  padding-bottom: 3px;
}

.page-about .ab-team__panel:nth-child(2) .ab-team__tag {
  color: var(--cyan);
  border-bottom-color: rgba(43, 245, 216, .5);
}

.page-about .ab-team__panel:nth-child(3) .ab-team__tag {
  color: var(--orange);
  border-bottom-color: rgba(255, 106, 31, .5);
}

.page-about .ab-team__panel:nth-child(4) .ab-team__tag {
  color: var(--clay);
  border-bottom-color: rgba(196, 112, 63, .5);
}

.page-about .ab-team__name {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(19px, 2.2vw, 23px);
  letter-spacing: -.01em;
  color: var(--paper);
}

.page-about .ab-team__desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.76;
  color: var(--text-dim);
}

.page-about .ab-team__more {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height .34s var(--ease), opacity .24s var(--ease), margin-top .34s var(--ease);
}

.page-about .ab-team__more p {
  margin: 0;
  padding-top: 14px;
  border-top: 1px dashed var(--line);
  font-size: 14px;
  line-height: 1.75;
  color: var(--paper);
}

.page-about .ab-team__panel:hover .ab-team__more,
.page-about .ab-team__panel:focus-within .ab-team__more,
.page-about .ab-team__panel:focus-visible .ab-team__more {
  max-height: 220px;
  opacity: 1;
  margin-top: 16px;
}

/* ---------- 流程 ---------- */
.page-about .ab-steps {
  border-top: 1px solid var(--line);
}

.page-about .ab-step__btn {
  display: flex;
  align-items: flex-start;
  gap: clamp(14px, 2.4vw, 24px);
  width: 100%;
  padding: clamp(16px, 2.4vw, 22px) 0;
  text-align: left;
  background: none;
  border: 0;
  border-bottom: 1px solid var(--line);
  cursor: pointer;
  color: inherit;
}

.page-about .ab-step__idx {
  flex: 0 0 auto;
  font-family: var(--font-serif);
  font-size: clamp(28px, 4vw, 44px);
  line-height: 1;
  color: var(--blue);
  opacity: .85;
  transition: color .2s var(--ease), opacity .2s var(--ease);
}

.page-about .ab-step__btn[aria-expanded="true"] .ab-step__idx,
.page-about .ab-step__btn:hover .ab-step__idx {
  color: var(--cyan);
  opacity: 1;
}

.page-about .ab-step__body {
  display: block;
  flex: 1 1 auto;
  min-width: 0;
}

.page-about .ab-step__name {
  display: block;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(17px, 2.1vw, 21px);
  letter-spacing: -.01em;
  color: var(--paper);
  margin-bottom: 6px;
}

.page-about .ab-step__sum {
  display: block;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--text-dim);
}

.page-about .ab-checks {
  list-style: none;
  margin: 0;
  padding: 14px 0 20px clamp(42px, 7vw, 68px);
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.page-about .ab-checks li {
  position: relative;
  padding-left: 20px;
  font-family: var(--font-mono);
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .ab-checks li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .78em;
  width: 12px;
  height: 2px;
  background: var(--orange);
}

/* ---------- 协作与覆盖 ---------- */
.page-about .ab-cover {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 48px);
  align-items: start;
}

.page-about .ab-cover__fig {
  margin: 0;
  overflow: hidden;
}

.page-about .ab-cover__fig img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  filter: saturate(.8) contrast(1.06);
}

.page-about .ab-cover__title {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(20px, 2.8vw, 30px);
  line-height: 1.3;
  letter-spacing: -.01em;
  color: var(--paper);
  max-width: 24ch;
}

.page-about .ab-cover__text {
  margin: 0 0 clamp(20px, 3vw, 30px);
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--text-dim);
  max-width: 62ch;
}

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

.page-about .ab-cover__list li {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
  padding: 15px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .ab-cover__key {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--cyan);
  min-width: 62px;
}

.page-about .ab-cover__val {
  flex: 1 1 220px;
  font-size: 14.5px;
  line-height: 1.74;
  color: var(--paper);
}

/* ---------- 标准 ---------- */
.page-about .ab-std {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(14px, 2vw, 22px);
}

.page-about .ab-std__card {
  padding: clamp(20px, 3vw, 28px);
  background: var(--rock);
}

.page-about .ab-std__idx {
  margin: 0 0 14px;
  font-family: var(--font-serif);
  font-size: 40px;
  line-height: 1;
  color: var(--blue);
  opacity: .28;
}

.page-about .ab-std__name {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(18px, 2.1vw, 22px);
  letter-spacing: -.01em;
  color: var(--paper);
}

.page-about .ab-std__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--text-dim);
}

/* ---------- 下一步 ---------- */
.page-about .ab-next {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-next__item {
  background: var(--ink);
  padding: clamp(22px, 3.4vw, 34px);
  transition: background .22s var(--ease);
}

.page-about .ab-next__item:hover {
  background: var(--rock);
}

.page-about .ab-next__num {
  display: block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .14em;
  color: var(--orange);
}

.page-about .ab-next__name {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(17px, 2vw, 21px);
  letter-spacing: -.01em;
  color: var(--paper);
}

.page-about .ab-next__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--text-dim);
}

/* ---------- 收束 ---------- */
.page-about .ab-cta {
  margin-top: clamp(64px, 9vw, 130px);
  padding: clamp(40px, 6vw, 72px) 0;
  background:
    linear-gradient(118deg, rgba(21, 87, 255, .22) 0%, rgba(11, 14, 19, 0) 62%),
    repeating-linear-gradient(298deg, rgba(43, 245, 216, .06) 0 1px, rgba(11, 14, 19, 0) 1px 30px),
    var(--rock);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .ab-cta__inner {
  display: flex;
  flex-direction: column;
  gap: clamp(22px, 3.4vw, 40px);
}

.page-about .ab-cta__title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(24px, 4.2vw, 42px);
  line-height: 1.18;
  letter-spacing: -.02em;
  color: var(--paper);
  max-width: 20ch;
}

.page-about .ab-cta__desc {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--text-dim);
  max-width: 58ch;
}

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

/* ---------- 平板以上 ---------- */
@media (min-width: 700px) {
  .page-about .ab-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

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

  .page-about .ab-cover {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  }

  .page-about .ab-cta__inner {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }

  .page-about .ab-cta__btns {
    flex: 0 0 auto;
    max-width: 46%;
    justify-content: flex-end;
  }
}

/* ---------- 桌面：顺时针对角动线 ---------- */
@media (min-width: 1080px) {
  .page-about .ab-split {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: start;
  }

  .page-about .ab-split--rev {
    grid-template-columns: minmax(0, 4fr) minmax(0, 8fr);
  }

  .page-about .ab-split--rev .ab-split__rail {
    padding-top: clamp(30px, 5vw, 76px);
  }

  .page-about .ab-split .ab-split__rail {
    position: sticky;
    top: calc(var(--header-h) + 24px);
  }

  .page-about .ab-split--rev .ab-split__main {
    padding-top: clamp(8px, 1.6vw, 20px);
  }

  .page-about .ab-team {
    grid-template-columns: repeat(6, minmax(0, 1fr));
    row-gap: clamp(18px, 2.4vw, 30px);
  }

  .page-about .ab-team__panel:nth-child(1) {
    grid-column: span 4;
  }

  .page-about .ab-team__panel:nth-child(2) {
    grid-column: span 2;
    margin-top: clamp(24px, 3.4vw, 46px);
  }

  .page-about .ab-team__panel:nth-child(3) {
    grid-column: 2 / span 2;
    margin-top: clamp(-6px, -1vw, 0px);
  }

  .page-about .ab-team__panel:nth-child(4) {
    grid-column: 4 / span 3;
    margin-top: clamp(-34px, -3.4vw, -18px);
  }

  .page-about .ab-std__card:nth-child(2) {
    margin-top: clamp(20px, 2.6vw, 36px);
  }

  .page-about .ab-std__card:nth-child(3) {
    margin-top: clamp(38px, 5vw, 66px);
  }

  .page-about .ab-cover {
    grid-template-columns: minmax(0, 4fr) minmax(0, 8fr);
    column-gap: clamp(36px, 5vw, 72px);
  }

  .page-about .ab-cover__body {
    padding-top: clamp(10px, 2vw, 28px);
  }
}

@media (min-width: 1300px) {
  .page-about .ab-hero__inner {
    padding-right: clamp(0px, 4vw, 60px);
  }

  .page-about .rail {
    right: max(14px, calc((100vw - var(--shell)) / 2 - 54px));
  }
}

/* ---------- 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .ab-team__panel,
  .page-about .ab-team__more,
  .page-about .ab-node::before,
  .page-about .ab-fact,
  .page-about .ab-next__item {
    transition: none;
  }

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