.page-about {
  --about-rail: 220px;
  --about-prose: 42rem;
  background: var(--ink-900);
  color: var(--paper);
}

.page-about .hero {
  padding-block: clamp(20px, 4vw, 40px) clamp(30px, 5vw, 58px);
  background:
    radial-gradient(120% 100% at 82% -10%, rgba(20, 61, 51, 0.95) 0%, rgba(5, 26, 21, 0) 62%),
    linear-gradient(180deg, rgba(12, 44, 36, 0.55) 0%, rgba(5, 26, 21, 0) 45%);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .crumbs__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  list-style: none;
  margin: 0 0 clamp(20px, 3vw, 34px);
  padding: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
}

.page-about .crumbs__item {
  display: flex;
  align-items: center;
  gap: 8px;
}

.page-about .crumbs__item + .crumbs__item::before {
  content: "/";
  color: var(--teal-line);
}

.page-about .crumbs__link {
  color: var(--paper-dim);
  text-decoration: none;
}

.page-about .crumbs__link:hover,
.page-about .crumbs__link:focus-visible {
  color: var(--cyan);
}

.page-about .crumbs__current {
  color: var(--cyan);
}

.page-about .hero__grid {
  align-items: start;
  gap: clamp(26px, 4vw, 48px);
}

.page-about .hero__title {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 7vw, 4.6rem);
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--chalk);
}

.page-about .hero__lede {
  margin: clamp(16px, 2.4vw, 24px) 0 0;
  max-width: 34rem;
  color: var(--paper-dim);
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.8;
}

.page-about .hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3vw, 32px);
}

.page-about .hero__actions .btn {
  min-height: 48px;
  display: inline-flex;
  align-items: center;
}

.page-about .board {
  position: relative;
  padding: 18px clamp(16px, 2.4vw, 22px) 16px;
  background: linear-gradient(160deg, var(--ink-800) 0%, var(--ink-900) 100%);
  border: 1px solid var(--line);
  clip-path: polygon(0 0, calc(100% - var(--cut)) 0, 100% var(--cut), 100% 100%, var(--cut) 100%, 0 calc(100% - var(--cut)));
}

.page-about .board::after {
  content: "";
  position: absolute;
  inset: auto 0 0 auto;
  width: 56%;
  height: 3px;
  background: linear-gradient(90deg, transparent, var(--cyan));
  opacity: 0.7;
}

.page-about .board__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 12px;
  border-bottom: 1px dashed var(--line-soft);
}

.page-about .board__stamp {
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--mist);
}

.page-about .board__list {
  list-style: none;
  margin: 0;
  padding: 6px 0 0;
}

.page-about .board__row {
  display: grid;
  grid-template-columns: 62px minmax(0, 1fr) auto;
  align-items: center;
  gap: 10px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .board__row:last-child {
  border-bottom: 0;
}

.page-about .board__time {
  font-size: 17px;
  color: var(--chalk);
  font-variant-numeric: tabular-nums;
}

.page-about .board__meta {
  font-size: 13px;
  color: var(--paper-dim);
  overflow-wrap: anywhere;
}

.page-about .board__foot {
  margin: 12px 0 0;
  font-size: 11px;
  line-height: 1.7;
  color: var(--mist);
  letter-spacing: 0.02em;
}

.page-about .hero__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(28px, 4vw, 44px) 0 0;
  padding: 0;
  list-style: none;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 16px;
  background: var(--ink-900);
}

.page-about .stat__num {
  font-size: clamp(20px, 2.6vw, 26px);
  color: var(--cyan);
  letter-spacing: -0.01em;
  font-variant-numeric: tabular-nums;
}

.page-about .stat__label {
  font-size: 12px;
  color: var(--mist);
  letter-spacing: 0.03em;
}

/* 章节索引 */
.page-about .about-body {
  padding-block: clamp(24px, 4vw, 44px) clamp(40px, 6vw, 72px);
}

.page-about .chapters {
  margin-bottom: clamp(24px, 4vw, 40px);
}

.page-about .chapters__title {
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--mist);
}

.page-about .chapters__list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 4px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .chapters__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  padding: 0 14px;
  white-space: nowrap;
  font-size: 13px;
  color: var(--paper);
  text-decoration: none;
  background: var(--ink-800);
  border: 1px solid var(--line-soft);
  clip-path: polygon(0 0, calc(100% - 10px) 0, 100% 10px, 100% 100%, 0 100%);
}

.page-about .chapters__link:hover,
.page-about .chapters__link:focus-visible {
  border-color: var(--cyan);
  color: var(--chalk);
}

.page-about .chapters__num {
  font-size: 11px;
  color: var(--cyan);
}

/* 章节通用 */
.page-about .chapter {
  padding-bottom: clamp(38px, 6vw, 68px);
}

.page-about .chapter + .chapter {
  padding-top: clamp(34px, 5vw, 58px);
  border-top: 1px solid var(--line-soft);
}

.page-about .sec-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  flex-wrap: wrap;
  margin-bottom: clamp(18px, 3vw, 28px);
  padding: 12px 18px 12px 14px;
  background: var(--paper);
  color: var(--ink-900);
  clip-path: polygon(0 0, calc(100% - 16px) 0, 100% 16px, 100% 100%, 0 100%);
}

.page-about .sec-head--alt {
  background: linear-gradient(100deg, var(--paper) 0%, var(--paper-dim) 100%);
}

.page-about .sec-head__num {
  font-size: clamp(1.5rem, 3vw, 2rem);
  line-height: 1;
  color: var(--teal-line);
  font-variant-numeric: tabular-nums;
}

.page-about .sec-head__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(1.25rem, 2.6vw, 1.85rem);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--ink-900);
}

.page-about .prose {
  max-width: var(--about-prose);
  margin: 0 0 18px;
  font-size: clamp(15px, 1.5vw, 16.5px);
  line-height: 1.85;
  color: var(--paper-dim);
}

.page-about .prose--lead {
  color: var(--paper);
  font-size: clamp(16px, 1.7vw, 18px);
}

.page-about .prose--quiet {
  color: var(--mist);
  font-size: 14px;
}

.page-about .aside-note {
  max-width: var(--about-prose);
  margin: 22px 0 26px;
  padding: 14px 0 14px 16px;
  border-left: 2px solid var(--cyan);
  background: linear-gradient(90deg, rgba(80, 242, 206, 0.07), transparent 78%);
}

.page-about .aside-note--wide {
  border-left-color: var(--orange);
  background: linear-gradient(90deg, rgba(255, 122, 42, 0.08), transparent 78%);
}

.page-about .aside-note__label {
  margin: 0 0 6px;
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .aside-note--wide .aside-note__label {
  color: var(--orange);
}

.page-about .aside-note p:last-child {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--paper-dim);
}

/* 图片 */
.page-about .media-frame {
  margin: 24px 0 26px;
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--ink-800);
}

.page-about .media-frame__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 16 / 10;
  object-fit: cover;
}

.page-about .media-frame--tall .media-frame__img {
  aspect-ratio: 4 / 3;
}

.page-about .media-frame__caption {
  padding: 10px 14px;
  font-size: 12px;
  line-height: 1.7;
  color: var(--mist);
  border-top: 1px solid var(--line-soft);
  background: var(--ink-800);
}

.page-about .scene-figure {
  max-width: 34rem;
}

/* 时间线 */
.page-about .timeline {
  position: relative;
  margin-top: clamp(28px, 4vw, 40px);
  padding-top: 4px;
}

.page-about .timeline__rail {
  position: absolute;
  top: 1px;
  left: 0;
  width: 100%;
  height: 16px;
  display: block;
}

.page-about .timeline__rail path {
  stroke: var(--teal-line);
  stroke-width: 1.5;
  stroke-dasharray: 6 7;
  fill: none;
  vector-effect: non-scaling-stroke;
}

.page-about .timeline__list {
  position: relative;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px 18px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .stage {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .stage__dot {
  width: 14px;
  height: 14px;
  margin-top: 1px;
  border-radius: 50%;
  border: 2px solid var(--teal-line);
  background: var(--ink-900);
}

.page-about .stage--now .stage__dot {
  border-color: var(--orange);
  box-shadow: 0 0 0 4px rgba(255, 122, 42, 0.16);
}

.page-about .stage__year {
  font-size: 15px;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .stage__label {
  font-size: 13.5px;
  color: var(--paper);
}

.page-about .stage__note {
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--mist);
  opacity: 0.72;
  transition: opacity 0.25s var(--ease), color 0.25s var(--ease);
}

.page-about .stage__note:hover,
.page-about .stage__note:focus-visible {
  opacity: 1;
  color: var(--paper);
  outline: none;
}

/* 场景卡 */
.page-about .scenes {
  display: grid;
  gap: 12px;
  margin: 4px 0 8px;
}

.page-about .scene {
  border: 1px solid var(--line-soft);
  background: var(--ink-800);
  clip-path: polygon(0 0, calc(100% - 12px) 0, 100% 12px, 100% 100%, 0 100%);
}

.page-about .scene[open] {
  border-color: var(--cyan);
}

.page-about .scene__head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 12px;
  min-height: 52px;
  padding: 12px 16px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .scene__head:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: -2px;
}

.page-about .scene__time {
  font-size: 12px;
  color: var(--cyan);
  letter-spacing: 0.04em;
  white-space: nowrap;
}

.page-about .scene__title {
  font-size: 15px;
  color: var(--chalk);
}

.page-about .scene__mark {
  width: 20px;
  height: 20px;
  display: grid;
  place-items: center;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--cyan);
  border: 1px solid var(--line);
  border-radius: 50%;
}

.page-about .scene__mark::before {
  content: "+";
  line-height: 1;
}

.page-about .scene[open] .scene__mark::before {
  content: "\2212";
}

.page-about .scene__body {
  margin: 0;
  padding: 0 16px 16px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--paper-dim);
}

/* 团队分工 */
.page-about .crew {
  display: grid;
  gap: 18px;
  margin: 22px 0 6px;
}

.page-about .crew__item {
  padding-bottom: 14px;
  border-bottom: 1px dashed var(--line-soft);
}

.page-about .crew__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin: 0 0 8px;
}

.page-about .crew__name {
  font-size: 14.5px;
  color: var(--paper);
}

.page-about .crew__num {
  font-size: 13px;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .crew__track {
  height: 5px;
  background: rgba(167, 196, 184, 0.16);
  overflow: hidden;
}

.page-about .crew__bar {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--teal-line), var(--cyan));
}

.page-about .crew__item:nth-child(1) .crew__bar { width: 32%; }
.page-about .crew__item:nth-child(2) .crew__bar { width: 24%; }
.page-about .crew__item:nth-child(3) .crew__bar { width: 29%; }
.page-about .crew__item:nth-child(4) .crew__bar { width: 16%; }

.page-about .crew__desc {
  margin: 8px 0 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--mist);
}

/* 稳定版卡 */
.page-about .stable-card {
  margin: 22px 0 26px;
  padding: clamp(18px, 3vw, 26px);
  background: linear-gradient(155deg, var(--ink-700) 0%, var(--ink-800) 70%);
  border: 1px solid var(--line);
}

.page-about .stable-card__title {
  margin: 8px 0 18px;
  font-family: var(--font-display);
  font-size: clamp(1.15rem, 2.2vw, 1.5rem);
  color: var(--chalk);
}

.page-about .metrics {
  display: grid;
  gap: 1px;
  margin: 0 0 18px;
  background: var(--line-soft);
}

.page-about .metrics__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px;
  padding: 10px 14px;
  background: var(--ink-800);
}

.page-about .metrics__row dt {
  font-size: 13px;
  color: var(--paper-dim);
}

.page-about .metrics__row dd {
  margin: 0;
  font-size: 13.5px;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
  text-align: right;
}

.page-about .chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 16px;
  padding: 0;
  list-style: none;
}

.page-about .chips__item {
  padding: 6px 12px;
  font-size: 12.5px;
  color: var(--paper);
  border: 1px solid var(--line);
  background: rgba(80, 242, 206, 0.06);
  clip-path: polygon(0 0, calc(100% - 8px) 0, 100% 8px, 100% 100%, 0 100%);
}

.page-about .stable-card__foot {
  margin: 0;
  padding-top: 14px;
  border-top: 1px dashed var(--line-soft);
  font-size: 11.5px;
  line-height: 1.7;
  color: var(--mist);
  letter-spacing: 0.02em;
}

.page-about .jump {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 8px;
}

.page-about .jump__link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-height: 48px;
  padding: 0 16px;
  font-size: 14px;
  color: var(--paper);
  text-decoration: none;
  border: 1px solid var(--line-soft);
  border-left: 3px solid var(--cyan);
  background: var(--ink-800);
}

.page-about .jump__link:hover,
.page-about .jump__link:focus-visible {
  background: var(--ink-700);
  color: var(--chalk);
}

.page-about .jump__arrow {
  color: var(--cyan);
}

/* 服务范围 */
.page-about .scope-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 20px 0 24px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .scope-item {
  padding: 16px 14px;
  background: var(--ink-800);
}

.page-about .scope-item__num {
  margin: 0 0 4px;
  font-size: clamp(22px, 3.4vw, 30px);
  color: var(--chalk);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.01em;
}

.page-about .scope-item__label {
  margin: 0;
  font-size: 12.5px;
  color: var(--mist);
}

.page-about .support {
  margin: 22px 0;
  padding: 18px;
  border: 1px solid var(--line);
  background: linear-gradient(120deg, rgba(0, 143, 120, 0.14), transparent 70%);
  clip-path: polygon(0 0, calc(100% - 14px) 0, 100% 14px, 100% 100%, 0 100%);
}

.page-about .support__label {
  margin: 0 0 8px;
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--orange);
}

.page-about .support__text {
  margin: 0 0 16px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--paper-dim);
}

.page-about .support__cta {
  display: inline-flex;
  align-items: center;
  min-height: 48px;
}

/* 尾部引导 */
.page-about .about-cta {
  padding-block: clamp(40px, 6vw, 72px);
  border-top: 1px solid var(--line-soft);
  background:
    repeating-linear-gradient(135deg, rgba(0, 143, 120, 0.12) 0 2px, transparent 2px 14px),
    linear-gradient(180deg, var(--ink-800) 0%, var(--ink-900) 100%);
}

.page-about .about-cta__title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 3.6vw, 2.3rem);
  color: var(--chalk);
  letter-spacing: -0.015em;
}

.page-about .about-cta__lede {
  max-width: 36rem;
  margin: 0 0 22px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--paper-dim);
}

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

.page-about .about-cta__links .btn {
  display: inline-flex;
  align-items: center;
  min-height: 48px;
}

@media (min-width: 620px) {
  .page-about .hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about .crew {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px 24px;
  }

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

  .page-about .timeline__list {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 14px;
  }
}

@media (min-width: 900px) {
  .page-about .about-body {
    display: grid;
    grid-template-columns: minmax(0, 1fr) var(--about-rail);
    column-gap: clamp(28px, 4vw, 56px);
    align-items: start;
  }

  .page-about .about-flow {
    grid-column: 1;
    grid-row: 1;
    min-width: 0;
  }

  .page-about .chapters {
    grid-column: 2;
    grid-row: 1;
    position: sticky;
    top: 96px;
    margin-bottom: 0;
    min-width: 0;
  }

  .page-about .chapters__list {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
    padding: 0;
    border-left: 1px solid var(--line-soft);
  }

  .page-about .chapters__link {
    width: 100%;
    justify-content: flex-start;
    background: transparent;
    border: 0;
    border-left: 2px solid transparent;
    margin-left: -1px;
    clip-path: none;
    padding: 10px 12px;
  }

  .page-about .chapters__link:hover,
  .page-about .chapters__link:focus-visible {
    border-left-color: var(--cyan);
    background: var(--ink-800);
  }

  .page-about .hero__title {
    font-size: clamp(3rem, 4.6vw, 4.6rem);
  }

  .page-about .board {
    margin-top: 6px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .stage__note {
    transition: none;
  }
}
<<<END>>>