.page-about {
  --ab-block: clamp(56px, 8vw, 104px);
  --ab-gap: clamp(20px, 3vw, 40px);
  --ab-line: 1px solid var(--bs-hair);
  --ab-line-dark: 1px solid var(--bs-hair-dark);
}

/* ============ HERO ============ */

.page-about .ab-hero {
  position: relative;
  margin-top: calc(-1 * var(--bs-header-h));
  padding: calc(var(--bs-header-h) + clamp(56px, 9vw, 108px)) 0 clamp(48px, 6vw, 80px);
  background: var(--bs-ink);
  overflow: hidden;
  isolation: isolate;
}

.page-about .ab-hero__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.26;
  filter: saturate(0.65) contrast(1.05);
  z-index: -2;
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    linear-gradient(180deg, rgba(28, 31, 38, 0.62) 0%, rgba(28, 31, 38, 0.88) 58%, var(--bs-ink) 100%),
    repeating-linear-gradient(90deg, rgba(0, 168, 232, 0.14) 0 1px, transparent 1px 80px);
}

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

.page-about .ab-hero .bs-breadcrumb {
  color: rgba(255, 255, 255, 0.62);
  margin-bottom: clamp(28px, 4vw, 48px);
}

.page-about .ab-hero .bs-breadcrumb a {
  color: rgba(255, 255, 255, 0.82);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 160ms var(--bs-ease), border-color 160ms var(--bs-ease);
}

.page-about .ab-hero .bs-breadcrumb a:hover,
.page-about .ab-hero .bs-breadcrumb a:focus-visible {
  color: var(--bs-ice-light);
  border-bottom-color: var(--bs-ice-light);
}

.page-about .ab-hero .bs-eyebrow {
  color: var(--bs-ice-light);
}

.page-about .ab-hero__title {
  color: var(--bs-paper);
  margin: 18px 0 0;
  max-width: 18em;
}

.page-about .ab-hero__lede {
  color: rgba(255, 255, 255, 0.76);
  max-width: 40em;
  margin-top: 22px;
  font-size: 16px;
  line-height: 1.8;
}

.page-about .ab-metrics {
  list-style: none;
  margin: clamp(36px, 5vw, 60px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--bs-hair-dark);
  border: 1px solid var(--bs-hair-dark);
}

.page-about .ab-metric {
  background: rgba(43, 48, 56, 0.72);
  padding: 18px 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .ab-metric__num {
  font-family: var(--bs-font-mono);
  font-size: clamp(26px, 3.4vw, 38px);
  font-weight: 700;
  line-height: 1;
  color: var(--bs-paper);
  letter-spacing: -0.02em;
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.page-about .ab-metric__unit {
  font-size: 12px;
  font-weight: 500;
  color: var(--bs-ice-light);
  letter-spacing: 0.04em;
}

.page-about .ab-metric__label {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: rgba(255, 255, 255, 0.58);
}

/* ============ 共用网格 ============ */

.page-about .bs-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--ab-gap);
}

.page-about .bs-col-rail {
  grid-column: span 2;
}

.page-about .bs-col-main {
  grid-column: span 7;
}

.page-about .bs-col-aside {
  grid-column: span 3;
}

.page-about .bs-measure {
  max-width: 38em;
}

.page-about .ab-head {
  max-width: 46em;
  margin-bottom: clamp(32px, 4vw, 56px);
}

.page-about .ab-head .bs-h2 {
  margin: 14px 0 16px;
}

.page-about .ab-head--dark .bs-h2 {
  color: var(--bs-paper);
}

.page-about .ab-head--dark .bs-lede {
  color: rgba(255, 255, 255, 0.68);
}

/* ============ 01 我们在做什么 ============ */

.page-about .ab-what {
  padding: var(--ab-block) 0;
  background: var(--bs-paper);
}

.page-about .ab-what .bs-rail {
  position: relative;
}

.page-about .ab-what .bs-rail__num {
  font-family: var(--bs-font-mono);
  font-size: clamp(48px, 7vw, 92px);
  font-weight: 700;
  line-height: 0.9;
  color: var(--bs-cloud);
  letter-spacing: -0.04em;
  display: block;
  position: sticky;
  top: calc(var(--bs-header-h) + 32px);
}

.page-about .ab-what .bs-h2 {
  margin: 12px 0 20px;
}

.page-about .ab-what p + p {
  margin-top: 1.2em;
}

.page-about .ab-what .bs-aside {
  border-top: 2px solid var(--bs-ink);
  padding-top: 16px;
  align-self: start;
}

.page-about .ab-what .bs-aside__item {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 12px 0;
  border-bottom: var(--ab-line);
  font-size: 14px;
}

.page-about .ab-what .bs-aside__key {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: rgba(28, 31, 38, 0.5);
}

/* ============ 02 九类条目 ============ */

.page-about .ab-standards {
  padding: var(--ab-block) 0;
}

.page-about .ab-folds {
  border-top: 2px solid var(--bs-ink);
}

.page-about .ab-item {
  border-bottom: var(--ab-line);
  background: transparent;
  transition: background-color 160ms var(--bs-ease);
}

.page-about .ab-item[open] {
  background: var(--bs-paper);
}

.page-about .ab-item__head {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr) auto 20px;
  align-items: center;
  gap: 16px;
  padding: 20px 4px 20px 0;
  cursor: pointer;
  list-style: none;
  position: relative;
  transition: color 160ms var(--bs-ease);
}

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

.page-about .ab-item__head::before {
  content: "";
  position: absolute;
  left: -16px;
  top: 6px;
  bottom: 6px;
  width: 2px;
  background: transparent;
  transition: background-color 160ms var(--bs-ease);
}

.page-about .ab-item__head:hover::before,
.page-about .ab-item__head:focus-visible::before {
  background: var(--bs-ice);
}

.page-about .ab-item__head:hover {
  background: var(--bs-ice-mist);
}

.page-about .ab-item__idx {
  font-size: 13px;
  color: var(--bs-ice-deep);
  letter-spacing: 0.06em;
}

.page-about .ab-item__name {
  font-family: var(--bs-font-display);
  font-weight: 700;
  font-size: clamp(17px, 1.8vw, 21px);
  color: var(--bs-ink);
  letter-spacing: -0.01em;
}

.page-about .ab-item__role {
  font-size: 12px;
  letter-spacing: 0.08em;
  padding: 4px 10px;
  color: var(--bs-ink);
  background: var(--bs-cloud);
  white-space: nowrap;
}

.page-about .ab-item[open] .ab-item__role {
  background: var(--bs-lime);
}

.page-about .ab-item__mark {
  position: relative;
  width: 12px;
  height: 12px;
}

.page-about .ab-item__mark::before,
.page-about .ab-item__mark::after {
  content: "";
  position: absolute;
  background: var(--bs-ink);
  transition: transform 160ms var(--bs-ease), opacity 160ms var(--bs-ease);
}

.page-about .ab-item__mark::before {
  left: 0;
  right: 0;
  top: 5px;
  height: 2px;
}

.page-about .ab-item__mark::after {
  top: 0;
  bottom: 0;
  left: 5px;
  width: 2px;
}

.page-about .ab-item[open] .ab-item__mark::after {
  transform: scaleY(0);
  opacity: 0;
}

.page-about .ab-item__body {
  padding: 0 4px 26px 64px;
}

.page-about .ab-item__body p {
  margin: 0 0 18px;
  max-width: 40em;
  color: rgba(28, 31, 38, 0.78);
  font-size: 15px;
  line-height: 1.8;
}

.page-about .ab-kv {
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: 10px 20px;
  margin: 0;
  padding: 16px 18px;
  background: var(--bs-ice-mist);
  border-left: 2px solid var(--bs-ice);
}

.page-about .ab-kv dt {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--bs-ice-deep);
  padding-top: 2px;
}

.page-about .ab-kv dd {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--bs-ink);
}

/* ============ 03 发展历程 ============ */

.page-about .ab-history {
  padding: var(--ab-block) 0;
}

.page-about .ab-tl {
  margin: 0 0 clamp(40px, 5vw, 64px);
}

.page-about .ab-tl__node {
  display: grid;
  grid-template-columns: 104px minmax(0, 1fr);
  gap: clamp(20px, 3vw, 44px);
  align-items: start;
  padding: 26px 0;
  border-top: var(--ab-line-dark);
}

.page-about .ab-tl__node:last-child {
  border-bottom: var(--ab-line-dark);
}

.page-about .ab-tl__year {
  position: relative;
  margin: 0;
  padding-left: 22px;
  font-family: var(--bs-font-mono);
  font-size: clamp(18px, 2.2vw, 26px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--bs-ice-light);
  white-space: nowrap;
}

.page-about .ab-tl__year::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.42em;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--bs-ice);
}

.page-about .ab-tl__node--now .ab-tl__year {
  color: var(--bs-lime);
}

.page-about .ab-tl__node--now .ab-tl__year::before {
  background: var(--bs-lime);
  box-shadow: 0 0 0 5px rgba(198, 255, 0, 0.16);
}

.page-about .ab-tl__body .bs-h3 {
  color: var(--bs-paper);
  margin: 0 0 10px;
  font-size: clamp(17px, 1.9vw, 21px);
}

.page-about .ab-tl__body p {
  margin: 0;
  max-width: 44em;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(255, 255, 255, 0.66);
}

.page-about .ab-figure {
  margin: 0;
  border: var(--ab-line-dark);
  background: rgba(43, 48, 56, 0.5);
}

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

.page-about .ab-figure .bs-figure__caption {
  padding: 14px 16px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: rgba(255, 255, 255, 0.55);
  border-top: var(--ab-line-dark);
}

/* ============ 04 团队与分工 ============ */

.page-about .ab-team {
  padding: var(--ab-block) 0;
  background: var(--bs-paper);
}

.page-about .ab-team__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 4vw, 52px);
  align-items: start;
}

.page-about .ab-team__media {
  margin: 0;
  border: var(--ab-line);
  background: var(--bs-cloud);
  box-shadow: var(--bs-shadow-1);
}

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

.page-about .ab-team__media .bs-figure__caption {
  padding: 14px 16px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: rgba(28, 31, 38, 0.6);
  border-top: var(--ab-line);
  background: var(--bs-paper);
}

.page-about .ab-compare {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  border-top: 2px solid var(--bs-ink);
}

.page-about .ab-compare__col {
  padding: 22px 0 26px;
  border-bottom: var(--ab-line);
}

.page-about .ab-compare__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
}

.page-about .ab-compare__head .bs-h3 {
  margin: 0;
}

.page-about .ab-compare__count {
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--bs-ink);
  background: var(--bs-lime);
  padding: 3px 10px;
  white-space: nowrap;
}

.page-about .ab-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-list li {
  position: relative;
  padding: 9px 0 9px 20px;
  font-size: 15px;
  line-height: 1.7;
  color: rgba(28, 31, 38, 0.8);
  border-bottom: var(--ab-line);
}

.page-about .ab-list li:last-child {
  border-bottom: 0;
}

.page-about .ab-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 18px;
  width: 8px;
  height: 2px;
  background: var(--bs-ice);
}

/* ============ 05 合作生态 ============ */

.page-about .ab-eco {
  padding: var(--ab-block) 0;
}

.page-about .ab-bars {
  list-style: none;
  margin: 0 0 clamp(32px, 4vw, 52px);
  padding: 0;
  border-top: 2px solid var(--bs-ink);
}

.page-about .ab-bar {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  grid-template-areas:
    "label value"
    "track track"
    "note note";
  gap: 8px 16px;
  align-items: center;
  padding: 18px 0;
  border-bottom: var(--ab-line);
}

.page-about .ab-bar__label {
  grid-area: label;
  font-family: var(--bs-font-display);
  font-weight: 700;
  font-size: 16px;
  color: var(--bs-ink);
}

.page-about .ab-bar__value {
  grid-area: value;
  font-size: 15px;
  color: var(--bs-ice-deep);
  white-space: nowrap;
}

.page-about .ab-bar__track {
  grid-area: track;
  display: block;
  height: 6px;
  background: var(--bs-cloud);
  overflow: hidden;
}

.page-about .ab-bar__fill {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--bs-ice) 0%, var(--bs-lime) 100%);
}

.page-about .ab-bar:nth-child(1) .ab-bar__fill { width: 38%; }
.page-about .ab-bar:nth-child(2) .ab-bar__fill { width: 54%; }
.page-about .ab-bar:nth-child(3) .ab-bar__fill { width: 82%; }
.page-about .ab-bar:nth-child(4) .ab-bar__fill { width: 100%; }

.page-about .ab-bar__note {
  grid-area: note;
  font-size: 13px;
  letter-spacing: 0.02em;
  color: rgba(28, 31, 38, 0.58);
}

.page-about .ab-license {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--bs-hair);
  border: 1px solid var(--bs-hair);
}

.page-about .ab-license__cell {
  background: var(--bs-paper);
  padding: 16px 18px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .ab-license__key {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: rgba(28, 31, 38, 0.5);
}

.page-about .ab-license__val {
  font-size: 14px;
  color: var(--bs-ink);
  word-break: break-word;
}

/* ============ 06 服务承诺 ============ */

.page-about .ab-promise {
  padding: var(--ab-block) 0 calc(var(--ab-block) * 1.1);
  background: var(--bs-paper);
}

.page-about .ab-promise__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--bs-hair);
  border: 1px solid var(--bs-hair);
}

.page-about .ab-promise__card {
  background: var(--bs-paper);
  padding: clamp(24px, 3vw, 34px);
  display: flex;
  flex-direction: column;
}

.page-about .ab-promise__card .bs-h3 {
  margin: 18px 0 12px;
}

.page-about .ab-promise__card p:last-child {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(28, 31, 38, 0.76);
}

.page-about .ab-promise__num {
  font-family: var(--bs-font-mono);
  font-size: clamp(40px, 5vw, 60px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--bs-ink);
  display: flex;
  align-items: baseline;
  gap: 6px;
  padding-bottom: 14px;
  border-bottom: 3px solid var(--bs-ice);
}

.page-about .ab-promise__unit {
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--bs-ice-deep);
}

.page-about .ab-cta {
  margin-top: clamp(36px, 5vw, 60px);
  padding: clamp(28px, 4vw, 44px);
  background: var(--bs-ink);
  color: var(--bs-paper);
}

.page-about .ab-cta__text {
  margin: 0 0 22px;
  font-size: clamp(18px, 2.2vw, 24px);
  font-family: var(--bs-font-display);
  font-weight: 700;
  line-height: 1.4;
  max-width: 26em;
}

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

.page-about .ab-cta .bs-btn--ghost {
  color: var(--bs-paper);
  border-color: rgba(255, 255, 255, 0.34);
}

.page-about .ab-cta .bs-btn--ghost:hover,
.page-about .ab-cta .bs-btn--ghost:focus-visible {
  color: var(--bs-ink);
  background: var(--bs-ice-light);
  border-color: var(--bs-ice-light);
}

.page-about .ab-cta__note {
  margin: 22px 0 0;
  font-size: 13px;
  line-height: 1.8;
  color: rgba(255, 255, 255, 0.6);
}

.page-about .ab-cta__note a {
  color: var(--bs-ice-light);
  text-decoration: none;
  border-bottom: 1px solid rgba(127, 216, 245, 0.5);
  transition: border-color 160ms var(--bs-ease);
}

.page-about .ab-cta__note a:hover,
.page-about .ab-cta__note a:focus-visible {
  border-bottom-color: var(--bs-lime);
}

/* ============ 焦点可见 ============ */

.page-about a:focus-visible,
.page-about summary:focus-visible,
.page-about .bs-btn:focus-visible {
  outline: 2px solid var(--bs-ice);
  outline-offset: 3px;
}

/* ============ 响应式 ============ */

@media (min-width: 640px) {
  .page-about .ab-metrics {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about .ab-compare {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0 clamp(24px, 3vw, 44px);
  }
}

@media (min-width: 880px) {
  .page-about .ab-team__grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  }

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

@media (min-width: 1080px) {
  .page-about .ab-bar {
    grid-template-columns: 180px minmax(0, 1fr) 110px;
    grid-template-areas:
      "label track value"
      "note note note";
    gap: 10px 24px;
  }
}

@media (max-width: 1079px) {
  .page-about .bs-col-rail {
    grid-column: span 12;
  }

  .page-about .bs-col-main {
    grid-column: span 12;
  }

  .page-about .bs-col-aside {
    grid-column: span 12;
  }

  .page-about .ab-what .bs-rail__num {
    position: static;
    font-size: 56px;
    margin-bottom: 4px;
  }

  .page-about .ab-what .bs-aside {
    margin-top: 8px;
  }
}

@media (max-width: 720px) {
  .page-about .ab-item__head {
    grid-template-columns: 36px minmax(0, 1fr) 18px;
    grid-template-areas:
      "idx name mark"
      ". role .";
    gap: 6px 12px;
    padding: 16px 0;
  }

  .page-about .ab-item__idx { grid-area: idx; }
  .page-about .ab-item__name { grid-area: name; }
  .page-about .ab-item__role { grid-area: role; justify-self: start; }
  .page-about .ab-item__mark { grid-area: mark; }

  .page-about .ab-item__head::before {
    left: -10px;
  }

  .page-about .ab-item__body {
    padding: 0 0 22px 0;
  }

  .page-about .ab-kv {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
    padding: 14px 14px;
  }

  .page-about .ab-kv dd {
    margin-bottom: 10px;
  }

  .page-about .ab-tl__node {
    grid-template-columns: minmax(0, 1fr);
    gap: 10px;
    padding: 22px 0;
  }

  .page-about .ab-cta__links .bs-btn {
    flex: 1 1 auto;
    text-align: center;
  }
}

@media (max-width: 400px) {
  .page-about .ab-metric {
    padding: 14px 14px;
  }

  .page-about .ab-compare__head {
    flex-wrap: wrap;
    gap: 8px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-item,
  .page-about .ab-item__head,
  .page-about .ab-item__head::before,
  .page-about .ab-item__mark::before,
  .page-about .ab-item__mark::after,
  .page-about .ab-bar__fill,
  .page-about a {
    transition: none !important;
    animation: none !important;
  }
}
</main>

.page-about {
  --ab-block: clamp(56px, 8vw, 104px);
  --ab-gap: clamp(20px, 3vw, 40px);
  --ab-line: 1px solid var(--bs-hair);
  --ab-line-dark: 1px solid var(--bs-hair-dark);
}

/* ============ HERO ============ */

.page-about .ab-hero {
  position: relative;
  margin-top: calc(-1 * var(--bs-header-h));
  padding: calc(var(--bs-header-h) + clamp(56px, 9vw, 108px)) 0 clamp(48px, 6vw, 80px);
  background: var(--bs-ink);
  overflow: hidden;
  isolation: isolate;
}

.page-about .ab-hero__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.26;
  filter: saturate(0.65) contrast(1.05);
  z-index: -2;
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    linear-gradient(180deg, rgba(28, 31, 38, 0.62) 0%, rgba(28, 31, 38, 0.88) 58%, var(--bs-ink) 100%),
    repeating-linear-gradient(90deg, rgba(0, 168, 232, 0.14) 0 1px, transparent 1px 80px);
}

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

.page-about .ab-hero .bs-breadcrumb {
  color: rgba(255, 255, 255, 0.62);
  margin-bottom: clamp(28px, 4vw, 48px);
}

.page-about .ab-hero .bs-breadcrumb a {
  color: rgba(255, 255, 255, 0.82);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 160ms var(--bs-ease), border-color 160ms var(--bs-ease);
}

.page-about .ab-hero .bs-breadcrumb a:hover,
.page-about .ab-hero .bs-breadcrumb a:focus-visible {
  color: var(--bs-ice-light);
  border-bottom-color: var(--bs-ice-light);
}

.page-about .ab-hero .bs-eyebrow {
  color: var(--bs-ice-light);
}

.page-about .ab-hero__title {
  color: var(--bs-paper);
  margin: 18px 0 0;
  max-width: 18em;
}

.page-about .ab-hero__lede {
  color: rgba(255, 255, 255, 0.76);
  max-width: 40em;
  margin-top: 22px;
  font-size: 16px;
  line-height: 1.8;
}

.page-about .ab-metrics {
  list-style: none;
  margin: clamp(36px, 5vw, 60px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--bs-hair-dark);
  border: 1px solid var(--bs-hair-dark);
}

.page-about .ab-metric {
  background: rgba(43, 48, 56, 0.72);
  padding: 18px 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .ab-metric__num {
  font-family: var(--bs-font-mono);
  font-size: clamp(26px, 3.4vw, 38px);
  font-weight: 700;
  line-height: 1;
  color: var(--bs-paper);
  letter-spacing: -0.02em;
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.page-about .ab-metric__unit {
  font-size: 12px;
  font-weight: 500;
  color: var(--bs-ice-light);
  letter-spacing: 0.04em;
}

.page-about .ab-metric__label {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: rgba(255, 255, 255, 0.58);
}

/* ============ 共用网格 ============ */

.page-about .bs-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--ab-gap);
}

.page-about .bs-col-rail {
  grid-column: span 2;
}

.page-about .bs-col-main {
  grid-column: span 7;
}

.page-about .bs-col-aside {
  grid-column: span 3;
}

.page-about .bs-measure {
  max-width: 38em;
}

.page-about .ab-head {
  max-width: 46em;
  margin-bottom: clamp(32px, 4vw, 56px);
}

.page-about .ab-head .bs-h2 {
  margin: 14px 0 16px;
}

.page-about .ab-head--dark .bs-h2 {
  color: var(--bs-paper);
}

.page-about .ab-head--dark .bs-lede {
  color: rgba(255, 255, 255, 0.68);
}

/* ============ 01 我们在做什么 ============ */

.page-about .ab-what {
  padding: var(--ab-block) 0;
  background: var(--bs-paper);
}

.page-about .ab-what .bs-rail {
  position: relative;
}

.page-about .ab-what .bs-rail__num {
  font-family: var(--bs-font-mono);
  font-size: clamp(48px, 7vw, 92px);
  font-weight: 700;
  line-height: 0.9;
  color: var(--bs-cloud);
  letter-spacing: -0.04em;
  display: block;
  position: sticky;
  top: calc(var(--bs-header-h) + 32px);
}

.page-about .ab-what .bs-h2 {
  margin: 12px 0 20px;
}

.page-about .ab-what p + p {
  margin-top: 1.2em;
}

.page-about .ab-what .bs-aside {
  border-top: 2px solid var(--bs-ink);
  padding-top: 16px;
  align-self: start;
}

.page-about .ab-what .bs-aside__item {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 12px 0;
  border-bottom: var(--ab-line);
  font-size: 14px;
}

.page-about .ab-what .bs-aside__key {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: rgba(28, 31, 38, 0.5);
}

/* ============ 02 九类条目 ============ */

.page-about .ab-standards {
  padding: var(--ab-block) 0;
}

.page-about .ab-folds {
  border-top: 2px solid var(--bs-ink);
}

.page-about .ab-item {
  border-bottom: var(--ab-line);
  background: transparent;
  transition: background-color 160ms var(--bs-ease);
}

.page-about .ab-item[open] {
  background: var(--bs-paper);
}

.page-about .ab-item__head {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr) auto 20px;
  align-items: center;
  gap: 16px;
  padding: 20px 4px 20px 0;
  cursor: pointer;
  list-style: none;
  position: relative;
  transition: background-color 160ms var(--bs-ease);
}

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

.page-about .ab-item__head::before {
  content: "";
  position: absolute;
  left: -16px;
  top: 6px;
  bottom: 6px;
  width: 2px;
  background: transparent;
  transition: background-color 160ms var(--bs-ease);
}

.page-about .ab-item__head:hover::before,
.page-about .ab-item__head:focus-visible::before {
  background: var(--bs-ice);
}

.page-about .ab-item__head:hover {
  background: var(--bs-ice-mist);
}

.page-about .ab-item__idx {
  font-family: var(--bs-font-mono);
  font-size: 13px;
  color: var(--bs-ice-deep);
  letter-spacing: 0.06em;
}

.page-about .ab-item__name {
  font-family: var(--bs-font-display);
  font-weight: 700;
  font-size: clamp(17px, 1.8vw, 21px);
  color: var(--bs-ink);
  letter-spacing: -0.01em;
}

.page-about .ab-item__role {
  font-size: 12px;
  letter-spacing: 0.08em;
  padding: 4px 10px;
  color: var(--bs-ink);
  background: var(--bs-cloud);
  white-space: nowrap;
}

.page-about .ab-item[open] .ab-item__role {
  background: var(--bs-lime);
}

.page-about .ab-item__mark {
  position: relative;
  width: 12px;
  height: 12px;
}

.page-about .ab-item__mark::before,
.page-about .ab-item__mark::after {
  content: "";
  position: absolute;
  background: var(--bs-ink);
  transition: transform 160ms var(--bs-ease), opacity 160ms var(--bs-ease);
}

.page-about .ab-item__mark::before {
  left: 0;
  right: 0;
  top: 5px;
  height: 2px;
}

.page-about .ab-item__mark::after {
  top: 0;
  bottom: 0;
  left: 5px;
  width: 2px;
}

.page-about .ab-item[open] .ab-item__mark::after {
  transform: scaleY(0);
  opacity: 0;
}

.page-about .ab-item__body {
  padding: 0 4px 26px 64px;
}

.page-about .ab-item__body p {
  margin: 0 0 18px;
  max-width: 40em;
  color: rgba(28, 31, 38, 0.78);
  font-size: 15px;
  line-height: 1.8;
}

.page-about .ab-kv {
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: 10px 20px;
  margin: 0;
  padding: 16px 18px;
  background: var(--bs-ice-mist);
  border-left: 2px solid var(--bs-ice);
}

.page-about .ab-kv dt {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--bs-ice-deep);
  padding-top: 2px;
}

.page-about .ab-kv dd {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--bs-ink);
}

/* ============ 03 发展历程 ============ */

.page-about .ab-history {
  padding: var(--ab-block) 0;
}

.page-about .ab-tl {
  margin: 0 0 clamp(40px, 5vw, 64px);
}

.page-about .ab-tl__node {
  display: grid;
  grid-template-columns: 104px minmax(0, 1fr);
  gap: clamp(20px, 3vw, 44px);
  align-items: start;
  padding: 26px 0;
  border-top: var(--ab-line-dark);
}

.page-about .ab-tl__node:last-child {
  border-bottom: var(--ab-line-dark);
}

.page-about .ab-tl__year {
  position: relative;
  margin: 0;
  padding-left: 22px;
  font-family: var(--bs-font-mono);
  font-size: clamp(18px, 2.2vw, 26px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--bs-ice-light);
  white-space: nowrap;
}

.page-about .ab-tl__year::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.42em;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--bs-ice);
}

.page-about .ab-tl__node--now .ab-tl__year {
  color: var(--bs-lime);
}

.page-about .ab-tl__node--now .ab-tl__year::before {
  background: var(--bs-lime);
  box-shadow: 0 0 0 5px rgba(198, 255, 0, 0.16);
}

.page-about .ab-tl__body .bs-h3 {
  color: var(--bs-paper);
  margin: 0 0 10px;
  font-size: clamp(17px, 1.9vw, 21px);
}

.page-about .ab-tl__body p {
  margin: 0;
  max-width: 44em;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(255, 255, 255, 0.66);
}

.page-about .ab-figure {
  margin: 0;
  border: var(--ab-line-dark);
  background: rgba(43, 48, 56, 0.5);
}

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

.page-about .ab-figure .bs-figure__caption {
  padding: 14px 16px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: rgba(255, 255, 255, 0.55);
  border-top: var(--ab-line-dark);
}

/* ============ 04 团队与分工 ============ */

.page-about .ab-team {
  padding: var(--ab-block) 0;
  background: var(--bs-paper);
}

.page-about .ab-team__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 4vw, 52px);
  align-items: start;
}

.page-about .ab-team__media {
  margin: 0;
  border: var(--ab-line);
  background: var(--bs-cloud);
  box-shadow: var(--bs-shadow-1);
}

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

.page-about .ab-team__media .bs-figure__caption {
  padding: 14px 16px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: rgba(28, 31, 38, 0.6);
  border-top: var(--ab-line);
  background: var(--bs-paper);
}

.page-about .ab-compare {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  border-top: 2px solid var(--bs-ink);
}

.page-about .ab-compare__col {
  padding: 22px 0 26px;
  border-bottom: var(--ab-line);
}

.page-about .ab-compare__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
}

.page-about .ab-compare__head .bs-h3 {
  margin: 0;
}

.page-about .ab-compare__count {
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--bs-ink);
  background: var(--bs-lime);
  padding: 3px 10px;
  white-space: nowrap;
}

.page-about .ab-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-list li {
  position: relative;
  padding: 9px 0 9px 20px;
  font-size: 15px;
  line-height: 1.7;
  color: rgba(28, 31, 38, 0.8);
  border-bottom: var(--ab-line);
}

.page-about .ab-list li:last-child {
  border-bottom: 0;
}

.page-about .ab-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 18px;
  width: 8px;
  height: 2px;
  background: var(--bs-ice);
}

/* ============ 05 合作生态 ============ */

.page-about .ab-eco {
  padding: var(--ab-block) 0;
}

.page-about .ab-bars {
  list-style: none;
  margin: 0 0 clamp(32px, 4vw, 52px);
  padding: 0;
  border-top: 2px solid var(--bs-ink);
}

.page-about .ab-bar {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  grid-template-areas:
    "label value"
    "track track"
    "note note";
  gap: 8px 16px;
  align-items: center;
  padding: 18px 0;
  border-bottom: var(--ab-line);
}

.page-about .ab-bar__label {
  grid-area: label;
  font-family: var(--bs-font-display);
  font-weight: 700;
  font-size: 16px;
  color: var(--bs-ink);
}

.page-about .ab-bar__value {
  grid-area: value;
  font-size: 15px;
  color: var(--bs-ice-deep);
  white-space: nowrap;
}

.page-about .ab-bar__track {
  grid-area: track;
  display: block;
  height: 6px;
  background: var(--bs-cloud);
  overflow: hidden;
}

.page-about .ab-bar__fill {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--bs-ice) 0%, var(--bs-lime) 100%);
}

.page-about .ab-bar:nth-child(1) .ab-bar__fill { width: 38%; }
.page-about .ab-bar:nth-child(2) .ab-bar__fill { width: 54%; }
.page-about .ab-bar:nth-child(3) .ab-bar__fill { width: 82%; }
.page-about .ab-bar:nth-child(4) .ab-bar__fill { width: 100%; }

.page-about .ab-bar__note {
  grid-area: note;
  font-size: 13px;
  letter-spacing: 0.02em;
  color: rgba(28, 31, 38, 0.58);
}

.page-about .ab-license {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--bs-hair);
  border: 1px solid var(--bs-hair);
}

.page-about .ab-license__cell {
  background: var(--bs-paper);
  padding: 16px 18px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .ab-license__key {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: rgba(28, 31, 38, 0.5);
}

.page-about .ab-license__val {
  font-size: 14px;
  color: var(--bs-ink);
  word-break: break-word;
}

/* ============ 06 服务承诺 ============ */

.page-about .ab-promise {
  padding: var(--ab-block) 0 calc(var(--ab-block) * 1.1);
  background: var(--bs-paper);
}

.page-about .ab-promise__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--bs-hair);
  border: 1px solid var(--bs-hair);
}

.page-about .ab-promise__card {
  background: var(--bs-paper);
  padding: clamp(24px, 3vw, 34px);
  display: flex;
  flex-direction: column;
}

.page-about .ab-promise__card .bs-h3 {
  margin: 18px 0 12px;
}

.page-about .ab-promise__card p:last-child {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(28, 31, 38, 0.76);
}

.page-about .ab-promise__num {
  font-family: var(--bs-font-mono);
  font-size: clamp(40px, 5vw, 60px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--bs-ink);
  display: flex;
  align-items: baseline;
  gap: 6px;
  padding-bottom: 14px;
  border-bottom: 3px solid var(--bs-ice);
}

.page-about .ab-promise__unit {
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--bs-ice-deep);
}

.page-about .ab-cta {
  margin-top: clamp(36px, 5vw, 60px);
  padding: clamp(28px, 4vw, 44px);
  background: var(--bs-ink);
  color: var(--bs-paper);
}

.page-about .ab-cta__text {
  margin: 0 0 22px;
  font-size: clamp(18px, 2.2vw, 24px);
  font-family: var(--bs-font-display);
  font-weight: 700;
  line-height: 1.4;
  max-width: 26em;
}

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

.page-about .ab-cta .bs-btn--ghost {
  color: var(--bs-paper);
  border-color: rgba(255, 255, 255, 0.34);
}

.page-about .ab-cta .bs-btn--ghost:hover,
.page-about .ab-cta .bs-btn--ghost:focus-visible {
  color: var(--bs-ink);
  background: var(--bs-ice-light);
  border-color: var(--bs-ice-light);
}

.page-about .ab-cta__note {
  margin: 22px 0 0;
  font-size: 13px;
  line-height: 1.8;
  color: rgba(255, 255, 255, 0.6);
}

.page-about .ab-cta__note a {
  color: var(--bs-ice-light);
  text-decoration: none;
  border-bottom: 1px solid rgba(127, 216, 245, 0.5);
  transition: border-color 160ms var(--bs-ease);
}

.page-about .ab-cta__note a:hover,
.page-about .ab-cta__note a:focus-visible {
  border-bottom-color: var(--bs-lime);
}

/* ============ 焦点可见 ============ */

.page-about a:focus-visible,
.page-about summary:focus-visible,
.page-about .bs-btn:focus-visible {
  outline: 2px solid var(--bs-ice);
  outline-offset: 3px;
}

/* ============ 响应式 ============ */

@media (min-width: 640px) {
  .page-about .ab-metrics {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about .ab-compare {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0 clamp(24px, 3vw, 44px);
  }
}

@media (min-width: 880px) {
  .page-about .ab-team__grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  }

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

@media (min-width: 1080px) {
  .page-about .ab-bar {
    grid-template-columns: 180px minmax(0, 1fr) 110px;
    grid-template-areas:
      "label track value"
      "note note note";
    gap: 10px 24px;
  }
}

@media (max-width: 1079px) {
  .page-about .bs-col-rail {
    grid-column: span 12;
  }

  .page-about .bs-col-main {
    grid-column: span 12;
  }

  .page-about .bs-col-aside {
    grid-column: span 12;
  }

  .page-about .ab-what .bs-rail__num {
    position: static;
    font-size: 56px;
    margin-bottom: 4px;
  }

  .page-about .ab-what .bs-aside {
    margin-top: 8px;
  }
}

@media (max-width: 720px) {
  .page-about .ab-item__head {
    grid-template-columns: 36px minmax(0, 1fr) 18px;
    grid-template-areas:
      "idx name mark"
      ". role .";
    gap: 6px 12px;
    padding: 16px 0;
  }

  .page-about .ab-item__idx { grid-area: idx; }
  .page-about .ab-item__name { grid-area: name; }
  .page-about .ab-item__role { grid-area: role; justify-self: start; }
  .page-about .ab-item__mark { grid-area: mark; }

  .page-about .ab-item__head::before {
    left: -10px;
  }

  .page-about .ab-item__body {
    padding: 0 0 22px 0;
  }

  .page-about .ab-kv {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
    padding: 14px 14px;
  }

  .page-about .ab-kv dd {
    margin-bottom: 10px;
  }

  .page-about .ab-tl__node {
    grid-template-columns: minmax(0, 1fr);
    gap: 10px;
    padding: 22px 0;
  }

  .page-about .ab-cta__links .bs-btn {
    flex: 1 1 auto;
    text-align: center;
  }
}

@media (max-width: 400px) {
  .page-about .ab-metric {
    padding: 14px 14px;
  }

  .page-about .ab-compare__head {
    flex-wrap: wrap;
    gap: 8px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-item,
  .page-about .ab-item__head,
  .page-about .ab-item__head::before,
  .page-about .ab-item__mark::before,
  .page-about .ab-item__mark::after,
  .page-about .ab-bar__fill,
  .page-about a {
    transition: none !important;
    animation: none !important;
  }
}