.page-about {
  --rail-w: 224px;
  --about-line: rgba(124, 246, 222, 0.16);
  --about-line-strong: rgba(124, 246, 222, 0.34);
  position: relative;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  overflow: clip;
  padding-top: calc(var(--header-h) + clamp(2.25rem, 6vw, 4.5rem));
  padding-bottom: clamp(2rem, 5vw, 3.5rem);
  isolation: isolate;
}

.page-about .about-hero__glow {
  position: absolute;
  top: -30%;
  right: -12%;
  width: min(760px, 88vw);
  aspect-ratio: 1 / 1;
  background: radial-gradient(circle at 58% 42%, rgba(34, 227, 195, 0.22), rgba(34, 227, 195, 0) 62%);
  pointer-events: none;
  z-index: -2;
}

.page-about .about-hero__slab {
  position: absolute;
  top: 14%;
  right: -14%;
  width: min(680px, 78vw);
  height: 58%;
  background: linear-gradient(138deg, rgba(14, 46, 42, 0.95), rgba(10, 31, 28, 0) 78%);
  border-radius: var(--radius-lg);
  transform: rotate(-7deg);
  pointer-events: none;
  z-index: -1;
}

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

.page-about .about-hero__crumbs {
  margin-bottom: clamp(1.25rem, 3vw, 2rem);
}

.page-about .about-hero__title {
  margin: 0.5rem 0 0;
  max-width: 18ch;
}

.page-about .about-hero__lede {
  margin-top: 1.25rem;
  max-width: 62ch;
  color: var(--text);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem 1.25rem;
  margin: clamp(1.75rem, 4vw, 2.75rem) 0 0;
  padding-top: 1.5rem;
  border-top: 1px solid var(--hairline);
  max-width: 820px;
}

@media (min-width: 760px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .about-fact {
  margin: 0;
}

.page-about .about-fact__label {
  font-size: 0.8125rem;
  color: var(--muted);
  letter-spacing: 0.04em;
  margin: 0 0 0.35rem;
}

.page-about .about-fact__num {
  margin: 0;
  font-size: clamp(1.125rem, 1.6vw, 1.5rem);
  font-weight: 700;
  color: var(--cyan);
  letter-spacing: 0.01em;
}

/* ---------- 外壳与索引 ---------- */

.page-about .about-shell {
  padding-bottom: clamp(3rem, 8vw, 6rem);
}

.page-about .about-shell__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.25rem, 4vw, 3.5rem);
  align-items: start;
}

@media (min-width: 1080px) {
  .page-about .about-shell__inner {
    grid-template-columns: var(--rail-w) minmax(0, 1fr);
  }
}

.page-about .about-index__head {
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  color: var(--muted);
  margin: 0 0 0.7rem;
}

.page-about .about-index__list {
  display: flex;
  flex-wrap: nowrap;
  gap: 0.5rem;
  list-style: none;
  margin: 0;
  padding: 0 0 0.5rem;
  overflow-x: auto;
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
}

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

.page-about .about-index__link {
  display: inline-block;
  white-space: nowrap;
  padding: 0.42rem 0.85rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--hairline);
  background: rgba(14, 46, 42, 0.6);
  color: var(--muted);
  font-size: 0.875rem;
  text-decoration: none;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  color: var(--text);
  border-color: var(--about-line-strong);
}

@media (min-width: 1080px) {
  .page-about .about-index {
    position: sticky;
    top: calc(var(--header-h) + 2rem);
    align-self: start;
    padding-bottom: 1rem;
  }

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

  .page-about .about-index__list > li {
    flex: initial;
  }

  .page-about .about-index__link {
    display: block;
    padding: 0.55rem 0 0.55rem 1rem;
    border: 0;
    border-left: 2px solid transparent;
    border-radius: 0;
    background: none;
    margin-left: -1px;
    font-size: 0.9375rem;
    white-space: normal;
  }

  .page-about .about-index__link:hover,
  .page-about .about-index__link:focus-visible {
    color: var(--cyan-soft);
    border-left-color: var(--about-line-strong);
  }

  .page-about .about-index__link.is-active {
    color: var(--cyan);
    border-left-color: var(--cyan);
    background: linear-gradient(90deg, rgba(34, 227, 195, 0.12), rgba(34, 227, 195, 0));
  }
}

/* ---------- 章节骨架 ---------- */

.page-about .about-flow {
  display: flex;
  flex-direction: column;
  gap: clamp(2.5rem, 7vw, 5rem);
  min-width: 0;
}

.page-about .about-chapter {
  scroll-margin-top: calc(var(--header-h) + 1.5rem);
  min-width: 0;
}

.page-about .about-chapter__head {
  display: flex;
  align-items: flex-start;
  gap: clamp(0.75rem, 2vw, 1.5rem);
  margin-bottom: clamp(1.25rem, 3vw, 2rem);
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--hairline);
}

.page-about .about-chapter__num {
  flex: none;
  font-size: 1rem;
  letter-spacing: 0.1em;
  color: var(--cyan);
  padding-top: 0.5rem;
}

.page-about .about-chapter__titles {
  min-width: 0;
}

.page-about .about-chapter__titles .section-title {
  margin: 0;
}

.page-about .about-chapter__intro {
  margin: 0.55rem 0 0;
  color: var(--muted);
  max-width: 64ch;
}

.page-about .about-body-text {
  margin: 0 0 1rem;
  max-width: 68ch;
  color: var(--text);
}

.page-about .about-body-text + .about-body-text {
  margin-top: 1rem;
}

.page-about .about-body-text a {
  color: var(--cyan-soft);
  text-decoration: none;
  border-bottom: 1px solid rgba(124, 246, 222, 0.4);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-body-text a:hover,
.page-about .about-body-text a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .stat-note {
  display: block;
  margin-top: clamp(1rem, 2.5vw, 1.5rem);
  padding-top: 0.85rem;
  border-top: 1px dashed var(--about-line);
  color: var(--muted);
  font-size: 0.8125rem;
  letter-spacing: 0.02em;
}

/* ---------- 时间线 ---------- */

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

.page-about .timeline__item {
  display: grid;
  grid-template-columns: 4.25rem minmax(0, 1fr);
  gap: 0.2rem 1rem;
  padding-bottom: 1.6rem;
}

@media (min-width: 720px) {
  .page-about .timeline__item {
    grid-template-columns: 7rem minmax(0, 1fr);
    gap: 0 2.25rem;
    padding-bottom: 1.9rem;
  }
}

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

.page-about .timeline__year {
  position: relative;
  margin: 0;
  padding-left: 1.35rem;
  padding-top: 0.1rem;
  font-size: 0.875rem;
  letter-spacing: 0.06em;
  color: var(--text);
}

.page-about .timeline__year::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.45rem;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 0 4px rgba(34, 227, 195, 0.14);
}

.page-about .timeline__item:not(:last-child) .timeline__year::after {
  content: "";
  position: absolute;
  left: 4px;
  top: 1.5rem;
  bottom: -1.6rem;
  width: 1px;
  background: linear-gradient(180deg, rgba(34, 227, 195, 0.44), rgba(34, 227, 195, 0.04));
}

.page-about .timeline__item--now .timeline__year {
  color: var(--orange);
}

.page-about .timeline__item--now .timeline__year::before {
  background: var(--orange);
  box-shadow: 0 0 0 4px rgba(255, 138, 61, 0.18);
}

.page-about .timeline__panel {
  min-width: 0;
}

.page-about .timeline__title {
  margin: 0 0 0.4rem;
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.4;
}

.page-about .timeline__lead {
  margin: 0;
  color: var(--muted);
  max-width: 62ch;
}

.page-about .timeline__more {
  margin-top: 0.85rem;
  border-radius: var(--radius-md);
  background: var(--ink-800);
  border: 1px solid var(--hairline);
  overflow: hidden;
}

.page-about .timeline__more summary {
  cursor: pointer;
  list-style: none;
  padding: 0.65rem 0.95rem;
  font-size: 0.875rem;
  color: var(--cyan-soft);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  transition: background var(--dur) var(--ease);
}

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

.page-about .timeline__more summary:hover {
  background: rgba(34, 227, 195, 0.07);
}

.page-about .timeline__more summary::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--muted);
  line-height: 1;
}

.page-about .timeline__more[open] summary::after {
  content: "–";
  color: var(--cyan);
}

.page-about .timeline__more-body {
  margin: 0;
  padding: 0 0.95rem 0.95rem;
  font-size: 0.9375rem;
  color: var(--muted);
  max-width: 60ch;
}

/* ---------- 宽幅停顿图 ---------- */

.page-about .about-pause {
  margin: 0;
}

.page-about .about-pause .media-frame {
  border-radius: var(--radius-lg);
}

.page-about .about-pause .media-caption {
  margin-top: 0.75rem;
  color: var(--muted);
  font-size: 0.8125rem;
}

/* ---------- 团队角色 ---------- */

.page-about .about-roles {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1rem;
}

@media (min-width: 780px) {
  .page-about .about-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-role {
  outline: none;
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-role:hover,
.page-about .about-role:focus-visible {
  transform: translateY(-3px);
}

.page-about .about-role__count {
  margin: 0.35rem 0 0.6rem;
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
  letter-spacing: 0.01em;
}

.page-about .about-role__keys {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  list-style: none;
  margin: 0.9rem 0 0;
  padding: 0;
}

@media (hover: hover) and (min-width: 900px) {
  .page-about .about-role__keys {
    opacity: 0;
    transform: translateY(8px);
    transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease);
  }

  .page-about .about-role:hover .about-role__keys,
  .page-about .about-role:focus-visible .about-role__keys,
  .page-about .about-role:focus-within .about-role__keys {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ---------- 数据来源 ---------- */

.page-about .about-sources {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.25rem, 3vw, 2.25rem);
  align-items: start;
}

@media (min-width: 920px) {
  .page-about .about-sources {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 1fr);
  }
}

.page-about .about-sources__figure {
  margin: 0;
}

.page-about .about-sources__figure .media-frame {
  border-radius: var(--radius-lg);
}

.page-about .about-sources__figure .media-caption {
  margin-top: 0.7rem;
  color: var(--muted);
  font-size: 0.8125rem;
}

.page-about .about-gates {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.85rem;
}

.page-about .about-gate {
  padding: 0.95rem 1.05rem 1rem 1.15rem;
  background: var(--ink-800);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--cyan);
}

.page-about .about-gate:nth-child(2) {
  border-left-color: var(--indigo);
}

.page-about .about-gate:nth-child(3) {
  border-left-color: var(--gold);
}

.page-about .about-gate__step {
  margin: 0 0 0.3rem;
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--muted);
}

.page-about .about-gate__title {
  margin: 0 0 0.4rem;
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--text);
}

.page-about .about-gate__text {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--muted);
  max-width: 52ch;
}

/* ---------- 对比方法 ---------- */

.page-about .about-fields {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  list-style: none;
  margin: 1.25rem 0;
  padding: 0;
}

/* ---------- 服务覆盖 ---------- */

.page-about .about-coverage {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1rem;
}

@media (min-width: 760px) {
  .page-about .about-coverage {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .about-coverage__card {
  display: flex;
  flex-direction: column;
}

.page-about .about-coverage__num {
  margin: 0.4rem 0 0;
  font-size: clamp(2.25rem, 4.4vw, 3rem);
  font-weight: 700;
  line-height: 1;
  color: var(--orange);
  letter-spacing: 0.01em;
}

.page-about .about-coverage__unit {
  margin: 0.35rem 0 0.9rem;
  font-size: 0.875rem;
  letter-spacing: 0.06em;
  color: var(--muted);
}

/* ---------- 观察报告与白皮书 ---------- */

.page-about .about-publishing {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.5rem, 4vw, 2.5rem);
  align-items: start;
}

@media (min-width: 880px) {
  .page-about .about-publishing {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.6fr);
  }
}

.page-about .about-publishing__figure {
  margin: 0;
}

.page-about .about-publishing__figure .media-frame {
  border-radius: var(--radius-lg);
}

.page-about .about-publishing__figure .media-caption {
  margin-top: 0.7rem;
  color: var(--muted);
  font-size: 0.8125rem;
}

.page-about .about-toc {
  margin: 1.25rem 0 1.35rem;
  border-radius: var(--radius-md);
  background: var(--ink-800);
  border: 1px solid var(--hairline);
  overflow: hidden;
}

.page-about .about-toc__summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.8rem 1rem;
  font-size: 0.9375rem;
  color: var(--cyan-soft);
  transition: background var(--dur) var(--ease);
}

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

.page-about .about-toc__summary:hover {
  background: rgba(34, 227, 195, 0.07);
}

.page-about .about-toc__summary::after {
  content: "+";
  font-family: var(--font-mono);
  color: var(--muted);
  line-height: 1;
}

.page-about .about-toc[open] .about-toc__summary::after {
  content: "–";
  color: var(--cyan);
}

.page-about .about-toc__list {
  list-style: none;
  margin: 0;
  padding: 0 1rem 1rem;
  display: grid;
  gap: 0.5rem;
}

.page-about .about-toc__item {
  display: flex;
  gap: 0.75rem;
  align-items: baseline;
  font-size: 0.9375rem;
  color: var(--muted);
  padding-top: 0.5rem;
  border-top: 1px solid var(--about-line);
}

.page-about .about-toc__item .mono {
  color: var(--cyan);
  font-size: 0.8125rem;
}

/* ---------- 未来方向 ---------- */

.page-about .about-roadmap {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1rem;
}

@media (min-width: 780px) {
  .page-about .about-roadmap {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

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

.page-about .about-road:hover {
  transform: translateY(-3px);
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-role,
  .page-about .about-road {
    transition: none;
  }

  .page-about .about-role:hover,
  .page-about .about-road:hover {
    transform: none;
  }

  .page-about .about-role__keys {
    opacity: 1;
    transform: none;
  }
}
<<<END>>>