.page-about {
  --ab-note: 104px;
  --ab-rule: 1px solid var(--hair);
  --ab-dark-rule: 1px solid rgba(195, 208, 222, .18);
  background: var(--paper-000);
  color: var(--graphite);
  font-family: var(--font-sans);
}

.page-about img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* ---------- 面包屑 ---------- */

.ab-crumb {
  padding-top: clamp(14px, 2.4vw, 22px);
  padding-bottom: clamp(10px, 1.8vw, 16px);
}

/* ---------- 首屏 ---------- */

.ab-hero {
  position: relative;
  overflow: hidden;
  background: var(--ink-900);
  color: var(--paper-000);
  padding: clamp(34px, 6vw, 60px) 0 clamp(46px, 8vw, 88px);
}

.ab-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--ink-800);
  clip-path: polygon(0 0, 100% 0, 100% 54%, 0 82%);
  z-index: 0;
}

.ab-hero::after {
  content: "";
  position: absolute;
  right: -12%;
  top: -24%;
  width: 52%;
  aspect-ratio: 1 / 1;
  background: radial-gradient(circle at 50% 50%, rgba(53, 227, 206, .18), rgba(53, 227, 206, 0) 68%);
  z-index: 0;
  pointer-events: none;
}

.ab-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(28px, 5vw, 48px);
}

@media (min-width: 900px) {
  .ab-hero__grid {
    grid-template-columns: 7fr 5fr;
    align-items: end;
  }
}

.ab-kicker {
  display: inline-flex;
  align-items: baseline;
  gap: 10px;
  margin: 0 0 18px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .14em;
  color: var(--cyan-500);
}

.ab-hero h1 {
  margin: 0;
  font-size: clamp(28px, 5.4vw, 44px);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.01em;
  max-width: 19em;
}

.ab-hero__lede {
  margin: clamp(16px, 2.6vw, 24px) 0 0;
  max-width: 36em;
  font-size: 16px;
  line-height: 1.85;
  color: rgba(247, 249, 252, .82);
}

.ab-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(24px, 4vw, 34px);
}

.ab-hero__side {
  border-top: var(--ab-dark-rule);
  padding-top: 20px;
}

.ab-hero__note {
  margin: 0;
  max-width: 30em;
  font-size: 14px;
  line-height: 1.8;
  color: rgba(247, 249, 252, .68);
}

.ab-metrics {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: rgba(195, 208, 222, .18);
  border: var(--ab-dark-rule);
}

.ab-metrics__item {
  background: rgba(7, 26, 50, .62);
  padding: 14px 16px;
}

.ab-metrics__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(22px, 3vw, 28px);
  line-height: 1.1;
  color: var(--cyan-500);
}

.ab-metrics__cap {
  display: block;
  margin-top: 8px;
  font-size: 12.5px;
  line-height: 1.55;
  color: rgba(247, 249, 252, .66);
}

/* ---------- 通用纵向区块 ---------- */

.ab-block {
  padding: clamp(48px, 8vw, 92px) 0;
  border-top: var(--ab-rule);
}

.ab-block--mist {
  background: var(--mist-200);
}

.ab-block--dark {
  background: var(--ink-900);
  color: var(--paper-000);
  border-top-color: transparent;
}

.ab-block__grid {
  display: grid;
  gap: 22px;
}

@media (min-width: 880px) {
  .ab-block__grid {
    grid-template-columns: var(--ab-note) minmax(0, 1fr);
    column-gap: clamp(24px, 4vw, 56px);
    align-items: start;
  }
}

.ab-block__title {
  margin: 0 0 clamp(24px, 4vw, 38px);
  font-size: clamp(22px, 3.4vw, 28px);
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.3;
}

.ab-block__body h2 {
  margin: 0 0 clamp(18px, 3vw, 26px);
  font-size: clamp(22px, 3.4vw, 28px);
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.3;
}

.ab-block__body p {
  max-width: 38em;
  font-size: 16px;
  line-height: 1.85;
  margin: 0 0 18px;
}

.ab-block__body p:last-child {
  margin-bottom: 0;
}

/* ---------- 左侧等宽旁注栏 ---------- */

.ab-side {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.ab-side__num {
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: .08em;
  color: var(--cyan-deep);
}

.ab-side__label {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .1em;
  color: var(--grey-500);
}

@media (min-width: 880px) {
  .ab-side {
    flex-direction: column;
    gap: 8px;
    align-self: start;
    position: sticky;
    top: calc(var(--masthead-h-tight) + 20px);
    padding-left: 14px;
    border-left: 1px solid var(--hair);
  }
}

.ab-block--dark .ab-side__num {
  color: var(--cyan-500);
}

.ab-block--dark .ab-side__label {
  color: rgba(247, 249, 252, .6);
}

.ab-block--dark .ab-side {
  border-left-color: rgba(195, 208, 222, .28);
}

/* ---------- 标签带 ---------- */

.ab-chips {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.ab-chips li {
  font-family: var(--font-mono);
  font-size: 13px;
  padding: 6px 12px;
  background: var(--cyan-100);
  color: var(--ink-800);
  border-radius: 2px;
}

/* ---------- 使用场景（错落排布） ---------- */

.ab-scenes {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

@media (min-width: 880px) {
  .ab-scenes {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    align-items: start;
  }
  .ab-scene:nth-child(1) { grid-column: 1 / 8; }
  .ab-scene:nth-child(2) { grid-column: 8 / 13; margin-top: 34px; }
  .ab-scene:nth-child(3) { grid-column: 3 / 12; }
}

.ab-scene {
  background: var(--paper-000);
  border: var(--ab-rule);
  border-left: 3px solid var(--ink-700);
  box-shadow: var(--shadow-1);
  padding: clamp(20px, 3vw, 30px);
}

.ab-scene:nth-child(2) { border-left-color: var(--amber-500); }
.ab-scene:nth-child(3) { border-left-color: var(--cyan-500); }

.ab-scene__tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .1em;
  color: var(--grey-500);
  margin-bottom: 10px;
}

.ab-scene h3 {
  margin: 0 0 12px;
  font-size: 19px;
  font-weight: 700;
  line-height: 1.4;
}

.ab-scene p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--graphite);
}

.ab-scene__link {
  display: inline-block;
  margin-top: 16px;
  font-size: 14px;
  color: var(--cyan-deep);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
  padding-bottom: 2px;
}

.ab-scene__link:hover {
  color: var(--ink-800);
}

/* ---------- 团队 ---------- */

.ab-team {
  display: grid;
  gap: 24px;
}

.ab-team__body h2 {
  margin: 0 0 18px;
  font-size: clamp(22px, 3.4vw, 28px);
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.3;
}

.ab-team__body p {
  max-width: 38em;
  font-size: 16px;
  line-height: 1.85;
  margin: 0 0 18px;
}

.ab-team__figure {
  margin: 0;
  border: var(--ab-rule);
  box-shadow: var(--shadow-1);
  background: var(--mist-200);
}

.ab-team__figure img {
  width: 100%;
  height: auto;
  object-fit: cover;
}

.ab-roles {
  display: grid;
  gap: 10px;
}

@media (min-width: 780px) {
  .ab-roles {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }
  .ab-role:nth-child(1) { grid-column: span 4; }
  .ab-role:nth-child(2) { grid-column: span 2; }
  .ab-role:nth-child(3) { grid-column: span 2; }
  .ab-role:nth-child(4) { grid-column: span 4; }
}

@media (min-width: 960px) {
  .ab-team {
    grid-template-columns: var(--ab-note) minmax(0, 1fr) minmax(0, 330px);
    grid-template-areas:
      "side .page-about figure"
      "side roles roles";
    column-gap: clamp(24px, 3.4vw, 48px);
    row-gap: 30px;
    align-items: start;
  }
  .ab-team .ab-side { grid-area: side; }
  .ab-team__body { grid-area: body; }
  .ab-team__figure { grid-area: figure; align-self: start; }
  .ab-roles { grid-area: roles; margin-top: 8px; }
}

.ab-role {
  background: var(--paper-000);
  border: var(--ab-rule);
  box-shadow: var(--shadow-1);
  border-left: 3px solid var(--ink-700);
}

.ab-role:nth-child(2) { border-left-color: var(--amber-500); }
.ab-role:nth-child(3) { border-left-color: var(--cyan-500); }
.ab-role:nth-child(4) { border-left-color: var(--ink-700); }

.page-about .fold__head {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
  padding: 16px 18px;
  background: none;
  border: 0;
  text-align: left;
  font: inherit;
  color: inherit;
  cursor: pointer;
}

.page-about .fold__index {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .08em;
  color: var(--cyan-deep);
  flex: 0 0 auto;
}

.page-about .fold__title {
  flex: 1 1 auto;
  font-size: 15.5px;
  font-weight: 700;
  line-height: 1.5;
}

.page-about .fold__arrow {
  flex: 0 0 auto;
  width: 9px;
  height: 9px;
  border-right: 2px solid var(--grey-500);
  border-bottom: 2px solid var(--grey-500);
  transform: rotate(45deg);
  transition: transform 240ms var(--ease);
}

.page-about .fold__head[aria-expanded="true"] .fold__arrow {
  transform: rotate(-135deg);
}

.page-about .fold__panel {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 240ms var(--ease);
}

.page-about .fold__head[aria-expanded="true"] + .fold__panel {
  grid-template-rows: 1fr;
}

.page-about .fold__inner {
  overflow: hidden;
}

.page-about .fold__body {
  padding: 0 18px 18px;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--grey-500);
}

.page-about .fold__body p {
  margin: 0;
}

/* ---------- 发展历程 ---------- */

.ab-history__figure {
  margin: 0 0 clamp(28px, 4vw, 44px);
  border: var(--ab-rule);
  box-shadow: var(--shadow-1);
  background: var(--ink-900);
}

.ab-history__figure img {
  width: 100%;
  height: auto;
  object-fit: cover;
}

.ab-tl {
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
}

.ab-tl::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 14px;
  bottom: 14px;
  width: 1px;
  background: linear-gradient(var(--cyan-500), var(--ink-700));
}

.ab-tl__item {
  position: relative;
  padding: 0 0 clamp(18px, 2.6vw, 26px) 40px;
}

.ab-tl__item:last-child {
  padding-bottom: 0;
}

.ab-tl__dot {
  position: absolute;
  left: 0;
  top: 8px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--paper-000);
  border: 2px solid var(--ink-700);
  box-sizing: border-box;
}

.ab-tl__item:first-child .ab-tl__dot {
  background: var(--cyan-500);
  border-color: var(--cyan-500);
}

.ab-tl__card {
  background: var(--paper-000);
  border: var(--ab-rule);
  border-left: 3px solid var(--ink-700);
  box-shadow: var(--shadow-1);
  padding: clamp(16px, 2.4vw, 22px);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease), border-left-color var(--dur) var(--ease);
}

.ab-tl__item:hover .ab-tl__card,
.ab-tl__item:focus-within .ab-tl__card {
  transform: translateY(-2px);
  box-shadow: var(--shadow-2);
  border-left-color: var(--cyan-500);
}

.ab-tl__year {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 13.5px;
  letter-spacing: .06em;
  color: var(--cyan-deep);
}

.ab-tl__card h3 {
  margin: 0 0 10px;
  font-size: 17.5px;
  font-weight: 700;
  line-height: 1.45;
}

.ab-tl__card p {
  margin: 0;
  max-width: 42em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--graphite);
}

/* ---------- 质量体系（深色面板） ---------- */

.ab-quality {
  display: grid;
  gap: clamp(28px, 5vw, 48px);
}

@media (min-width: 940px) {
  .ab-quality {
    grid-template-columns: 7fr 5fr;
    align-items: start;
  }
}

.ab-quality h2 {
  margin: 0 0 16px;
  font-size: clamp(22px, 3.4vw, 28px);
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.3;
  color: var(--paper-000);
}

.ab-quality__lede {
  margin: 0 0 26px;
  max-width: 34em;
  font-size: 15.5px;
  line-height: 1.85;
  color: rgba(247, 249, 252, .74);
}

.ab-quality__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: rgba(195, 208, 222, .18);
  border: var(--ab-dark-rule);
}

.ab-quality__list li {
  background: var(--ink-900);
  padding: 16px 18px;
}

.ab-quality__k {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: .04em;
  color: var(--cyan-500);
}

.ab-quality__v {
  display: block;
  font-size: 14.5px;
  line-height: 1.8;
  color: rgba(247, 249, 252, .76);
}

.ab-quality__figure {
  margin: 0;
  border: var(--ab-dark-rule);
  overflow: hidden;
}

.ab-quality__figure img {
  width: 100%;
  height: auto;
  object-fit: cover;
  opacity: .92;
}

/* ---------- 数据带 ---------- */

.ab-stats {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--hair);
  border: var(--ab-rule);
}

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

.ab-stats li {
  background: var(--paper-000);
  padding: 18px 16px;
}

.ab-stats__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(21px, 2.6vw, 29px);
  line-height: 1.1;
  color: var(--ink-800);
}

.ab-stats__cap {
  display: block;
  margin-top: 8px;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--grey-500);
}

/* ---------- 覆盖信息表 ---------- */

.ab-cover {
  margin: 26px 0 0;
  border-top: var(--ab-rule);
}

.ab-cover__row {
  display: grid;
  gap: 4px;
  padding: 14px 0;
  border-bottom: var(--ab-rule);
}

@media (min-width: 620px) {
  .ab-cover__row {
    grid-template-columns: 160px minmax(0, 1fr);
    align-items: baseline;
    gap: 20px;
  }
}

.ab-cover dt {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--grey-500);
}

.ab-cover dd {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--graphite);
}

.ab-cover .cn {
  font-family: var(--font-mono);
  color: var(--ink-800);
}

/* ---------- 行动区 ---------- */

.ab-cta {
  background: var(--ink-800);
  color: var(--paper-000);
  padding: clamp(40px, 7vw, 72px) 0;
  border-top: var(--ab-dark-rule);
}

.ab-cta__inner {
  display: grid;
  gap: 24px;
}

@media (min-width: 860px) {
  .ab-cta__inner {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    gap: clamp(28px, 5vw, 60px);
  }
}

.ab-cta h2 {
  margin: 0 0 12px;
  font-size: clamp(21px, 3.2vw, 27px);
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.32;
  color: var(--paper-000);
}

.ab-cta p {
  margin: 0;
  max-width: 36em;
  font-size: 15.5px;
  line-height: 1.85;
  color: rgba(247, 249, 252, .74);
}

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

@media (prefers-reduced-motion: reduce) {
  .page-about .fold__arrow,
  .page-about .fold__panel,
  .ab-tl__card {
    transition: none;
  }
  .ab-tl__item:hover .ab-tl__card,
  .ab-tl__item:focus-within .ab-tl__card {
    transform: none;
  }
}