.page-about {
  --about-rail: 208px;
  --about-gap: clamp(20px, 3vw, 44px);
  background: var(--snow);
  color: var(--ink-blue);
}

.page-about .about-br {
  display: none;
}

/* 面包屑 */
.page-about .breadcrumb {
  padding-top: 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--mid);
}

.page-about .breadcrumb a {
  color: var(--ink-blue);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--maple);
  border-bottom-color: var(--maple);
}

.page-about .breadcrumb__sep {
  margin: 0 8px;
  color: var(--line);
}

/* 首屏 */
.page-about .about-hero {
  padding: clamp(24px, 4vw, 52px) 0 clamp(36px, 6vw, 76px);
}

.page-about .about-hero__grid {
  display: grid;
  gap: var(--about-gap);
  align-items: start;
}

.page-about .about-hero h1 {
  margin: 14px 0 0;
  font-family: var(--font-sans);
  font-weight: 900;
  font-size: clamp(2rem, 7.2vw, 3.5rem);
  line-height: 1.12;
  letter-spacing: -0.025em;
  color: var(--ink);
}

.page-about .about-hero__lead {
  margin: clamp(16px, 2vw, 24px) 0 0;
  max-width: 35em;
  font-size: clamp(15px, 2.2vw, 17px);
  line-height: 1.78;
  color: var(--ink-blue);
}

.page-about .about-hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 22px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  color: var(--ink-blue);
}

.page-about .about-key {
  display: inline-block;
  margin-right: 7px;
  padding: 1px 6px;
  background: var(--ink);
  color: var(--snow);
  font-size: 10px;
  letter-spacing: 0.12em;
}

.page-about .about-hero__figure {
  position: relative;
  margin: 0;
  border: 1px solid var(--line);
  background: var(--white);
}

.page-about .about-hero__figure::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 92px;
  height: 6px;
  background: var(--maple);
  z-index: 2;
}

.page-about .about-hero__figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
}

.page-about .about-hero__figure figcaption {
  padding: 12px 16px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.03em;
  color: var(--mid);
}

/* 正文骨架 */
.page-about .about-body {
  padding-bottom: clamp(36px, 5vw, 72px);
}

.page-about .about-layout {
  display: grid;
  gap: var(--about-gap);
  align-items: start;
}

/* 章节索引 */
.page-about .about-index {
  border-top: 2px solid var(--ink);
  padding-top: 12px;
  min-width: 0;
}

.page-about .about-index__title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--mid);
}

.page-about .about-index__list {
  display: flex;
  gap: 4px;
  margin: 0;
  padding: 0;
  list-style: none;
  overflow-x: auto;
  border-bottom: 1px solid var(--line);
  scrollbar-width: thin;
}

.page-about .about-index__list li {
  flex: none;
}

.page-about .about-index__link {
  display: block;
  padding: 9px 12px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
  color: var(--ink-blue);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  white-space: nowrap;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  color: var(--maple);
  border-bottom-color: var(--maple);
}

.page-about .about-index__link:focus-visible {
  outline: 2px solid var(--deep-teal);
  outline-offset: 2px;
}

.page-about .about-index__num {
  margin-right: 8px;
  color: var(--teal);
}

.page-about .about-index__link:hover .about-index__num {
  color: var(--maple);
}

/* 长文流 */
.page-about .about-stream {
  min-width: 0;
}

.page-about .about-block {
  padding: clamp(26px, 4vw, 44px) 0;
  border-top: 1px solid var(--line);
  scroll-margin-top: calc(var(--header-h) + 20px);
}

.page-about .about-block:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-block__num {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--maple);
}

.page-about .about-block h2 {
  margin: 0 0 16px;
  font-family: var(--font-sans);
  font-weight: 800;
  font-size: clamp(1.3rem, 3.4vw, 1.95rem);
  line-height: 1.32;
  letter-spacing: -0.015em;
  color: var(--ink);
  max-width: 24em;
}

.page-about .about-block .prose {
  max-width: 60ch;
  margin: 0 0 14px;
  font-size: 15.5px;
  line-height: 1.82;
  color: var(--ink-blue);
}

.page-about .about-inline {
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--maple);
  transition: color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-inline:hover {
  color: var(--maple);
  background: var(--alert);
}

.page-about .about-inline:focus-visible {
  outline: 2px solid var(--deep-teal);
  outline-offset: 2px;
}

/* 技术标签 */
.page-about .about-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-tags .tag {
  padding: 4px 10px;
  background: var(--white);
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.03em;
  color: var(--ink-blue);
}

/* 时间轴 */
.page-about .about-timeline {
  position: relative;
  margin-top: 26px;
  padding-left: 34px;
  isolation: isolate;
}

.page-about .about-timeline__bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  overflow: hidden;
  opacity: 0.14;
  pointer-events: none;
}

.page-about .about-timeline__bg img {
  width: 100%;
  height: 100%;
  max-width: 100%;
  object-fit: cover;
}

.page-about .about-axis {
  position: absolute;
  top: 0;
  left: 4px;
  width: 2px;
  height: 100%;
  color: var(--line);
  z-index: 1;
}

.page-about .timeline {
  position: relative;
  z-index: 2;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .timeline__item {
  position: relative;
  padding-bottom: clamp(20px, 3vw, 30px);
}

.page-about .timeline__item:last-child {
  padding-bottom: 0;
}

.page-about .timeline__dot {
  position: absolute;
  left: -34px;
  top: 7px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--teal);
  box-shadow: 0 0 0 3px var(--snow);
  transition: background var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .timeline__item:hover .timeline__dot,
.page-about .timeline__item:focus-within .timeline__dot {
  background: var(--maple);
  transform: scale(1.4);
}

.page-about .timeline__item--now .timeline__dot {
  background: var(--maple);
}

.page-about .timeline__body {
  transition: transform var(--dur) var(--ease);
}

.page-about .timeline__item:hover .timeline__body,
.page-about .timeline__item:focus-within .timeline__body {
  transform: translateX(3px);
}

.page-about .timeline__year {
  margin: 0 0 5px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--maple);
}

.page-about .timeline__body h3 {
  margin: 0 0 6px;
  font-size: clamp(1rem, 2.6vw, 1.14rem);
  font-weight: 700;
  line-height: 1.45;
  color: var(--ink);
}

.page-about .timeline__note {
  margin: 0;
  max-width: 54ch;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--ink-blue);
  opacity: 0.76;
  transition: opacity var(--dur) var(--ease);
}

.page-about .timeline__item:hover .timeline__note,
.page-about .timeline__item:focus-within .timeline__note {
  opacity: 1;
}

/* 团队 */
.page-about .about-team {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
  margin-top: 22px;
  align-items: start;
}

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

.page-about .about-groups__item {
  padding: 14px 0;
  border-top: 1px solid var(--line);
}

.page-about .about-groups__item:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-groups__code {
  display: inline-block;
  margin-bottom: 6px;
  padding: 1px 6px;
  background: var(--snow);
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.12em;
  color: var(--deep-teal);
}

.page-about .about-groups__item h3 {
  margin: 0 0 6px;
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-groups__item p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--ink-blue);
}

.page-about .about-team__figure {
  margin: 0;
  border: 1px solid var(--line);
  background: var(--white);
}

.page-about .about-team__figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 10 / 7;
  object-fit: cover;
}

.page-about .about-team__figure figcaption {
  padding: 11px 14px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--mid);
}

.page-about .about-team__tail {
  margin-top: 22px;
}

/* 服务原则 */
.page-about .about-principles {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
  margin-top: 6px;
  align-items: start;
}

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

.page-about .about-principles__list li {
  padding: 14px 0 14px 16px;
  border-left: 2px solid var(--line);
  transition: border-color var(--dur) var(--ease);
}

.page-about .about-principles__list li:hover {
  border-left-color: var(--teal);
}

.page-about .about-principles__list h3 {
  margin: 0 0 6px;
  font-size: 15.5px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-principles__list p {
  margin: 0;
  max-width: 48ch;
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--ink-blue);
}

.page-about .about-note {
  padding: clamp(20px, 3vw, 28px);
  background: var(--ink-blue);
  color: var(--snow);
}

.page-about .about-note__kicker {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--teal);
}

.page-about .about-note__big {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: clamp(2rem, 5.5vw, 2.8rem);
  font-weight: 600;
  letter-spacing: -0.03em;
  color: var(--white);
  line-height: 1;
}

.page-about .about-note__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--line);
}

/* 数字里程碑 */
.page-about .about-metrics {
  display: grid;
  gap: 1px;
  margin-top: 24px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .metric {
  background: var(--white);
  padding: clamp(18px, 2.6vw, 26px);
  transition: box-shadow var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .metric:hover {
  box-shadow: inset 0 -3px 0 var(--teal);
}

.page-about .metric:focus-visible {
  outline: 2px solid var(--deep-teal);
  outline-offset: -2px;
}

.page-about .metric--lg {
  background: var(--ink);
}

.page-about .metric__num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(1.75rem, 5vw, 2.5rem);
  font-weight: 600;
  line-height: 1.05;
  letter-spacing: -0.03em;
  color: var(--maple);
}

.page-about .metric__num span {
  margin-left: 4px;
  font-size: 0.42em;
  letter-spacing: 0;
  color: var(--mid);
}

.page-about .metric--lg .metric__num {
  font-size: clamp(2.3rem, 7vw, 3.6rem);
  color: var(--white);
}

.page-about .metric--lg .metric__num span {
  color: var(--line);
}

.page-about .metric__label {
  margin: 10px 0 0;
  font-size: 14px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .metric--lg .metric__label {
  color: var(--snow);
}

.page-about .metric__desc {
  margin: 6px 0 0;
  font-size: 13px;
  line-height: 1.66;
  color: var(--mid);
}

.page-about .metric--lg .metric__desc {
  max-width: 40ch;
  color: var(--line);
}

/* 下一步 */
.page-about .about-next {
  padding: clamp(32px, 5vw, 60px) 0;
  background: var(--white);
  border-top: 2px solid var(--ink);
}

.page-about .about-next__grid {
  display: grid;
  gap: clamp(22px, 3vw, 40px);
  align-items: start;
}

.page-about .about-next__intro h2 {
  margin: 12px 0 12px;
  font-size: clamp(1.3rem, 3.4vw, 1.8rem);
  font-weight: 800;
  line-height: 1.32;
  letter-spacing: -0.015em;
  color: var(--ink);
}

.page-about .about-next__intro .prose {
  margin: 0;
  max-width: 34ch;
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--ink-blue);
}

.page-about .about-next__list {
  display: grid;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
  min-width: 0;
}

.page-about .about-next__link {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 12px;
  padding: 13px 16px;
  background: var(--snow);
  border-left: 2px solid var(--line);
  text-decoration: none;
  color: var(--ink);
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-next__link:hover {
  border-left-color: var(--maple);
  background: var(--white);
}

.page-about .about-next__link:focus-visible {
  outline: 2px solid var(--deep-teal);
  outline-offset: 2px;
  border-left-color: var(--maple);
}

.page-about .about-next__name {
  font-size: 15px;
  font-weight: 700;
}

.page-about .about-next__desc {
  flex: 1 1 auto;
  min-width: 0;
  font-size: 13px;
  line-height: 1.6;
  color: var(--mid);
}

.page-about .about-next__arrow {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--maple);
}

/* 平板与桌面 */
@media (min-width: 760px) {
  .page-about .about-br {
    display: inline;
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
  }

  .page-about .about-team {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
  }

  .page-about .about-principles {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
  }

  .page-about .about-metrics {
    grid-template-columns: repeat(6, 1fr);
  }

  .page-about .metric--lg {
    grid-column: span 6;
  }

  .page-about .metric--md {
    grid-column: span 3;
  }

  .page-about .metric--sm {
    grid-column: span 2;
  }

  .page-about .about-next__grid {
    grid-template-columns: minmax(0, 4fr) minmax(0, 7fr);
  }
}

@media (min-width: 900px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(32px, 4.5vw, 64px);
  }

  .page-about .about-index {
    position: sticky;
    top: calc(var(--header-h) + 28px);
  }

  .page-about .about-index__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    border-bottom: 0;
  }

  .page-about .about-index__link {
    padding: 10px 0 10px 14px;
    border-bottom: 0;
    border-left: 2px solid var(--line);
    white-space: normal;
  }

  .page-about .about-index__link:hover,
  .page-about .about-index__link:focus-visible {
    border-left-color: var(--maple);
    border-bottom-color: transparent;
  }

  .page-about .about-block h2 {
    margin-bottom: 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .timeline__dot,
  .page-about .timeline__body,
  .page-about .timeline__note,
  .page-about .metric,
  .page-about .about-next__link,
  .page-about .about-index__link {
    transition: none;
  }

  .page-about .timeline__item:hover .timeline__dot,
  .page-about .timeline__item:focus-within .timeline__dot {
    transform: none;
  }

  .page-about .timeline__item:hover .timeline__body,
  .page-about .timeline__item:focus-within .timeline__body {
    transform: none;
  }
}
<<<END>>>