.page-about {
  --about-line: 1px solid var(--concrete);
  --about-offset: calc(var(--header-h) + 24px);
  overflow-x: hidden;
}

.page-about .about-top {
  padding-top: var(--s5);
}

/* 首屏 */
.page-about .about-hero {
  display: grid;
  gap: var(--s6);
  padding-top: var(--s5);
  padding-bottom: var(--s7);
  border-bottom: var(--about-line);
}

.page-about .about-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 6.4vw, 3.4rem);
  line-height: 1.08;
  letter-spacing: -0.01em;
  font-weight: 700;
  color: var(--bone);
  margin: var(--s3) 0 var(--s4);
}

.page-about .about-hero .lede {
  max-width: 58ch;
  margin: 0;
}

.page-about .about-hero .lede a {
  color: var(--bone);
  text-decoration: none;
  border-bottom: 1px solid var(--red);
  padding-bottom: 1px;
}

.page-about .about-hero .lede a:hover {
  color: var(--red-bright);
  border-bottom-color: var(--red-bright);
}

.page-about .about-hero__points {
  list-style: none;
  margin: var(--s5) 0 0;
  padding: 0;
  display: grid;
  gap: var(--s3);
}

.page-about .about-hero__points li {
  position: relative;
  padding-left: var(--s5);
  color: var(--steel);
  font-size: 0.9375rem;
  line-height: 1.6;
}

.page-about .about-hero__points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.55em;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--mint);
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    align-items: end;
    gap: var(--s7);
    padding-top: var(--s6);
    padding-bottom: var(--s8);
  }
}

/* 图片容器 */
.page-about .about-figure {
  margin: 0;
  border: 1px solid var(--concrete);
  background: var(--stand);
  padding: 0;
}

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

.page-about .about-figure .media__caption {
  padding: var(--s3) var(--s4);
  border-top: 1px solid var(--concrete);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.02em;
  color: var(--mist);
}

/* 数字带 */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: var(--about-line);
  border-bottom: var(--about-line);
}

.page-about .about-stat {
  padding: var(--s5) var(--s3) var(--s5) 0;
  border-bottom: var(--about-line);
  min-width: 0;
}

.page-about .about-stat:nth-child(even) {
  padding-left: var(--s4);
  border-left: var(--about-line);
}

.page-about .about-stat:nth-child(3),
.page-about .about-stat:nth-child(4) {
  border-bottom: none;
}

.page-about .about-stat__num {
  margin: 0;
  font-size: clamp(1.6rem, 4.4vw, 2.5rem);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--bone);
}

.page-about .about-stat__num span {
  font-family: var(--font-body);
  font-size: 0.75rem;
  letter-spacing: 0;
  color: var(--mist);
  margin-left: 0.35em;
}

.page-about .about-stat__label {
  margin: var(--s3) 0 0;
  font-size: 0.8125rem;
  line-height: 1.65;
  color: var(--mist);
}

@media (min-width: 820px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-stat {
    padding: var(--s5) var(--s5) var(--s5) 0;
    border-bottom: none;
    border-left: none;
  }

  .page-about .about-stat:nth-child(even) {
    padding-left: 0;
  }

  .page-about .about-stat + .about-stat {
    padding-left: var(--s5);
    border-left: var(--about-line);
  }
}

/* 主体：左侧目录 + 章节 */
.page-about .about-body {
  display: grid;
  gap: var(--s6);
  padding-top: var(--s7);
  padding-bottom: var(--s7);
}

.page-about .about-toc__title {
  margin: 0 0 var(--s3);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--red-bright);
}

.page-about .about-toc__list {
  list-style: none;
  margin: 0;
  padding: 0 0 var(--s2);
  display: flex;
  gap: var(--s2);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-toc__list li {
  flex: 0 0 auto;
}

.page-about .about-toc__list a {
  display: inline-flex;
  align-items: center;
  gap: var(--s2);
  padding: var(--s2) var(--s4);
  border: 1px solid var(--concrete);
  border-radius: 999px;
  color: var(--steel);
  font-size: 0.8125rem;
  text-decoration: none;
  white-space: nowrap;
  transition: color 200ms ease, border-color 200ms ease;
}

.page-about .about-toc__list a .mono {
  color: var(--mist);
  font-size: 0.6875rem;
}

.page-about .about-toc__list a:hover,
.page-about .about-toc__list a:focus-visible {
  color: var(--bone);
  border-color: var(--red);
}

@media (min-width: 1000px) {
  .page-about .about-body {
    grid-template-columns: 200px minmax(0, 1fr);
    gap: var(--s7);
    align-items: start;
  }

  .page-about .about-toc {
    position: sticky;
    top: var(--about-offset);
    align-self: start;
  }

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

  .page-about .about-toc__list a {
    border: 0;
    border-radius: 0;
    border-left: 2px solid transparent;
    margin-left: -1px;
    padding: var(--s2) var(--s4);
    background: none;
    white-space: normal;
  }

  .page-about .about-toc__list a:hover,
  .page-about .about-toc__list a:focus-visible {
    border-left-color: var(--red);
  }
}

/* 章节骨架 */
.page-about .about-sections {
  min-width: 0;
}

.page-about .about-sec {
  padding-bottom: var(--s7);
  border-bottom: var(--about-line);
  margin-bottom: var(--s7);
  scroll-margin-top: var(--about-offset);
}

.page-about .about-sec:last-of-type {
  border-bottom: none;
  margin-bottom: 0;
  padding-bottom: var(--s5);
}

.page-about .section__head {
  display: flex;
  align-items: flex-end;
  gap: var(--s4);
  margin-bottom: var(--s4);
}

.page-about .section-index {
  font-family: var(--font-serif);
  font-size: clamp(3rem, 9vw, 6rem);
  line-height: 0.75;
  color: var(--bone);
  opacity: 0.18;
  flex: 0 0 auto;
  transition: opacity 300ms ease;
}

.page-about .about-sec.is-active .section-index {
  opacity: 1;
}

.page-about .section__title {
  font-family: var(--font-display);
  font-size: clamp(1.25rem, 3vw, 1.75rem);
  font-weight: 700;
  letter-spacing: 0.01em;
  line-height: 1.25;
  color: var(--bone);
  margin: 0 0 0.2em;
}

.page-about .section__lamp {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--concrete);
  margin-bottom: 0.85em;
  flex: 0 0 auto;
  transition: background 300ms ease, box-shadow 300ms ease;
}

.page-about .about-sec.is-active .section__lamp {
  background: var(--mint);
  box-shadow: 0 0 0 4px rgba(35, 224, 168, 0.14);
}

.page-about .about-sec__intro {
  margin: 0 0 var(--s6);
  max-width: 62ch;
  color: var(--steel);
  font-size: 0.9375rem;
  line-height: 1.8;
}

.page-about .about-sec__note {
  margin: var(--s6) 0 0;
  padding-top: var(--s4);
  border-top: 1px dashed var(--concrete);
  color: var(--mist);
  font-size: 0.875rem;
  line-height: 1.8;
}

.page-about .about-sec__note a {
  color: var(--bone);
  text-decoration: none;
  border-bottom: 1px solid var(--red);
}

.page-about .about-sec__note a:hover {
  color: var(--red-bright);
}

/* 时间线 */
.page-about .about-timeline {
  position: relative;
  display: grid;
  padding-left: var(--s5);
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 0;
  top: var(--s4);
  bottom: var(--s4);
  width: 1px;
  background: var(--concrete);
}

.page-about .about-node {
  position: relative;
  border-top: var(--about-line);
  padding: var(--s4) 0;
}

.page-about .about-node::before {
  content: "";
  position: absolute;
  left: calc(-1 * var(--s5) - 4px);
  top: calc(var(--s4) + 5px);
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--concrete);
  transition: background 220ms ease;
}

.page-about .about-node[open]::before {
  background: var(--mint);
}

.page-about .about-node summary {
  list-style: none;
  cursor: pointer;
  display: grid;
  gap: var(--s1);
  padding-right: var(--s5);
  position: relative;
}

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

.page-about .about-node summary:focus-visible {
  outline: 1px solid var(--mint);
  outline-offset: 4px;
}

.page-about .about-node__year {
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  color: var(--red-bright);
}

.page-about .about-node__title {
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--bone);
  line-height: 1.35;
}

.page-about .about-node__toggle {
  position: absolute;
  right: 0;
  top: 0;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--mist);
}

.page-about .about-node__toggle::before {
  content: "＋";
}

.page-about .about-node[open] .about-node__toggle::before {
  content: "－";
  color: var(--mint);
}

.page-about .about-node p {
  margin: var(--s3) 0 0;
  max-width: 54ch;
  color: var(--steel);
  font-size: 0.9375rem;
  line-height: 1.8;
}

@media (min-width: 860px) {
  .page-about .about-timeline {
    padding-left: 0;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    column-gap: var(--s7);
    align-items: start;
  }

  .page-about .about-timeline::before {
    left: 50%;
    top: 0;
    bottom: 0;
  }

  .page-about .about-node:nth-child(odd) {
    grid-column: 1;
    padding: var(--s4) var(--s5) var(--s4) 0;
  }

  .page-about .about-node:nth-child(even) {
    grid-column: 2;
    margin-top: var(--s7);
    padding: var(--s4) 0 var(--s4) var(--s5);
    border-top: var(--about-line);
  }

  .page-about .about-node:nth-child(odd)::before {
    left: auto;
    right: calc(-1 * (var(--s7) / 2) - 4px);
    top: calc(var(--s4) + 5px);
  }

  .page-about .about-node:nth-child(even)::before {
    left: calc(-1 * (var(--s7) / 2) - 4px);
    top: calc(var(--s4) + 5px);
  }
}

/* 栏目索引卡 */
.page-about .about-map {
  display: grid;
  border-top: var(--about-line);
  border-left: var(--about-line);
}

.page-about .about-card {
  padding: var(--s5) var(--s4);
  border-right: var(--about-line);
  border-bottom: var(--about-line);
  min-width: 0;
  transition: background-color 220ms ease;
}

.page-about .about-card:hover,
.page-about .about-card:focus-within {
  background: var(--stand);
}

.page-about .about-card__kicker {
  margin: 0 0 var(--s3);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  color: var(--red-bright);
}

.page-about .about-card__title {
  margin: 0 0 var(--s3);
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--bone);
}

.page-about .about-card__desc {
  margin: 0 0 var(--s4);
  color: var(--steel);
  font-size: 0.9375rem;
  line-height: 1.8;
}

.page-about .about-card__meta {
  margin: 0 0 var(--s4);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  color: var(--mist);
  opacity: 0.7;
  transition: opacity 220ms ease, color 220ms ease;
}

.page-about .about-card:hover .about-card__meta,
.page-about .about-card:focus-within .about-card__meta {
  opacity: 1;
  color: var(--mint);
}

.page-about .about-card__link {
  display: inline-block;
  font-size: 0.8125rem;
  color: var(--bone);
  text-decoration: none;
  border-bottom: 1px solid var(--concrete);
  padding-bottom: 2px;
  transition: border-color 200ms ease, color 200ms ease;
}

.page-about .about-card__link:hover,
.page-about .about-card__link:focus-visible {
  color: var(--red-bright);
  border-bottom-color: var(--red-bright);
}

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

  .page-about .about-card {
    padding: var(--s6) var(--s5);
  }
}

/* 小组分工 */
.page-about .about-team {
  display: grid;
  gap: var(--s6);
}

.page-about .about-roles {
  display: grid;
}

.page-about .about-role {
  border-top: var(--about-line);
  padding: var(--s4) 0;
}

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

.page-about .about-role h3 {
  margin: 0 0 var(--s2);
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--bone);
}

.page-about .about-role p {
  margin: 0;
  color: var(--steel);
  font-size: 0.9375rem;
  line-height: 1.8;
}

@media (min-width: 900px) {
  .page-about .about-team {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
    gap: var(--s7);
    align-items: start;
  }
}

.page-about .about-flow {
  list-style: none;
  margin: var(--s6) 0 0;
  padding: 0;
  display: grid;
  gap: var(--s3);
  counter-reset: none;
}

.page-about .about-flow__item {
  display: grid;
  grid-template-columns: 32px minmax(0, 1fr);
  gap: var(--s3);
  align-items: start;
  padding: var(--s3) 0;
  border-top: 1px dashed var(--concrete);
}

.page-about .about-flow__num {
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--mint);
  padding-top: 0.25em;
}

.page-about .about-flow__item p {
  margin: 0;
  color: var(--steel);
  font-size: 0.9375rem;
  line-height: 1.7;
}

@media (min-width: 680px) {
  .page-about .about-flow {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: var(--s6);
  }
}

/* 服务范围 */
.page-about .about-reach {
  display: grid;
  gap: var(--s6);
}

.page-about .about-reach__text p {
  margin: 0 0 var(--s4);
  color: var(--steel);
  font-size: 0.9375rem;
  line-height: 1.85;
  max-width: 56ch;
}

.page-about .about-reach__text p:first-child {
  color: var(--bone);
}

.page-about .about-reach__contact {
  padding-top: var(--s4);
  border-top: 1px solid var(--concrete);
  color: var(--mist) !important;
  font-size: 0.875rem !important;
}

.page-about .about-reach__text a {
  color: var(--bone);
  text-decoration: none;
  border-bottom: 1px solid var(--red);
}

.page-about .about-reach__text a:hover {
  color: var(--red-bright);
}

@media (min-width: 900px) {
  .page-about .about-reach {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.95fr);
    gap: var(--s7);
    align-items: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc__list a,
  .page-about .about-card,
  .page-about .about-card__meta,
  .page-about .section-index,
  .page-about .section__lamp,
  .page-about .about-node::before {
    transition: none;
  }
}
<<<END>>>