.page-about {
  --about-gap: clamp(28px, 5vw, 64px);
  --about-rule: 1px solid var(--line);
  display: block;
}

/* ---------- 面包屑 ---------- */
.page-about .about-top {
  padding-top: clamp(16px, 2.4vw, 28px);
  padding-bottom: clamp(8px, 1.4vw, 16px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: clamp(24px, 4vw, 48px);
  padding-bottom: clamp(36px, 6vw, 72px);
  align-items: center;
  border-bottom: var(--about-rule);
}

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

.page-about .about-hero h1 {
  margin: 10px 0 0;
  font-size: clamp(2.1rem, 5.4vw, 3.6rem);
  line-height: 1.06;
  letter-spacing: -0.02em;
  color: var(--fog);
}

.page-about .about-hero__lede {
  margin: 18px 0 0;
  max-width: 46ch;
  font-family: var(--serif);
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.85;
  color: var(--mist);
}

.page-about .about-hero__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(22px, 3vw, 34px);
  background: var(--line);
  border: var(--about-rule);
}

.page-about .about-stat {
  background: var(--night);
  padding: 14px 14px 16px;
  min-width: 0;
}

.page-about .about-stat__value {
  display: block;
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  line-height: 1;
  color: var(--lime);
  letter-spacing: -0.02em;
}

.page-about .about-stat__unit {
  font-size: 0.5em;
  margin-left: 2px;
  color: var(--mist);
}

.page-about .about-stat__label {
  display: block;
  margin-top: 8px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--mist);
  line-height: 1.5;
}

.page-about .about-hero__media {
  position: relative;
  margin: 0;
  min-width: 0;
  border: var(--about-rule);
  overflow: hidden;
  clip-path: polygon(0 0, 100% 0, 100% 86%, 14% 100%);
  background: var(--steel);
}

.page-about .about-hero__media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  filter: saturate(0.72) brightness(0.92);
}

/* ---------- 主体双区 ---------- */
.page-about .about-body {
  display: grid;
  gap: var(--about-gap);
  padding-block: clamp(36px, 6vw, 72px) clamp(56px, 8vw, 96px);
}

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

.page-about .about-toc__label {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--mist);
}

.page-about .about-toc__list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-toc__link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 44px;
  padding: 6px 12px;
  border: var(--about-rule);
  background: var(--steel);
  color: var(--fog);
  font-size: 13px;
  text-decoration: none;
  transition: border-color 140ms ease, background-color 140ms ease;
}

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

.page-about .about-toc__link:hover,
.page-about .about-toc__link:focus-visible {
  border-color: var(--orange);
  background: var(--board);
}

.page-about .about-chapters {
  min-width: 0;
  display: grid;
  gap: clamp(8px, 1.4vw, 16px);
}

/* ---------- 章节 ---------- */
.page-about .about-chapter {
  display: grid;
  gap: clamp(14px, 2vw, 22px);
  padding-block: clamp(26px, 4vw, 44px);
  border-top: var(--about-rule);
  scroll-margin-top: calc(var(--topbar-h) + 24px);
}

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

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

.page-about .about-chapter__num {
  display: block;
  font-size: clamp(3rem, 7vw, 6rem);
  font-weight: 200;
  line-height: 0.86;
  letter-spacing: -0.05em;
  color: var(--line);
}

.page-about .about-chapter__lede {
  margin: 14px 0 0;
  padding-left: 12px;
  border-left: 2px solid var(--orange);
  max-width: 20ch;
  font-size: 14px;
  line-height: 1.7;
  color: var(--fog);
}

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

.page-about .about-chapter__title {
  margin: 0 0 16px;
  font-size: clamp(1.25rem, 2.4vw, 1.65rem);
  font-weight: 600;
  line-height: 1.3;
  color: var(--fog);
  letter-spacing: -0.01em;
}

.page-about .about-chapter__text {
  margin: 0 0 14px;
  max-width: 62ch;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .about-chapter__text:last-child {
  margin-bottom: 0;
}

/* ---------- 事实条 ---------- */
.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border: var(--about-rule);
}

.page-about .about-facts__item {
  background: var(--steel);
  padding: 14px 12px;
  min-width: 0;
}

.page-about .about-facts__k {
  display: block;
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--lime);
  line-height: 1.1;
}

.page-about .about-facts__v {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  color: var(--mist);
  line-height: 1.5;
}

/* ---------- 团队配比 ---------- */
.page-about .about-team {
  margin-top: 24px;
}

.page-about .about-team__label {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--mist);
}

.page-about .about-team__bars {
  display: grid;
  grid-template-columns: 22fr 14fr;
  gap: 8px;
}

.page-about .about-team__bar {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
  padding: 14px 12px;
  background: var(--board);
  border: var(--about-rule);
}

.page-about .about-team__bar--edit {
  border-left: 3px solid var(--orange);
}

.page-about .about-team__bar--data {
  border-left: 3px solid var(--grass);
}

.page-about .about-team__count {
  font-size: clamp(1.4rem, 3vw, 1.9rem);
  font-weight: 700;
  line-height: 1;
  color: var(--fog);
}

.page-about .about-team__role {
  font-size: 13px;
  color: var(--fog);
  line-height: 1.4;
}

.page-about .about-team__duty {
  font-size: 11.5px;
  color: var(--mist);
  line-height: 1.4;
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 26px 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  filter: saturate(0.7);
}

.page-about .about-figure .media-frame__caption {
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--mist);
}

/* ---------- 栏目折叠 ---------- */
.page-about .about-columns {
  display: grid;
  gap: 8px;
  margin-top: 22px;
}

.page-about .about-col {
  background: var(--steel);
  border: var(--about-rule);
  transition: border-color 160ms ease;
}

.page-about .about-col[open] {
  border-color: var(--orange);
  background: var(--board);
}

.page-about .about-col__summary {
  display: grid;
  grid-template-columns: 2.2rem minmax(0, 1fr) 22px;
  grid-template-areas:
    "idx name plus"
    "idx hint plus";
  align-items: center;
  gap: 2px 10px;
  min-height: 44px;
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-col__idx {
  grid-area: idx;
  font-size: 12px;
  color: var(--orange);
}

.page-about .about-col__name {
  grid-area: name;
  font-size: 15.5px;
  font-weight: 600;
  color: var(--fog);
}

.page-about .about-col__hint {
  grid-area: hint;
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--mist);
}

.page-about .about-col__summary::after {
  content: "+";
  grid-area: plus;
  justify-self: end;
  font-family: var(--mono);
  font-size: 18px;
  line-height: 1;
  color: var(--mist);
  transition: color 160ms ease;
}

.page-about .about-col[open] .about-col__summary::after {
  content: "−";
  color: var(--orange);
}

.page-about .about-col__body {
  padding: 0 16px 16px 3.4rem;
}

.page-about .about-col__body p {
  margin: 0;
  max-width: 58ch;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 版本时间线 ---------- */
.page-about .about-timeline {
  position: relative;
  list-style: none;
  margin: 24px 0 0;
  padding: 0 0 0 26px;
  display: grid;
  gap: 20px;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--line);
}

.page-about .about-timeline__item {
  position: relative;
  min-width: 0;
  padding-left: 6px;
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 8px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--night);
  border: 2px solid var(--orange);
  box-sizing: content-box;
}

.page-about .about-timeline__year {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--lime);
}

.page-about .about-timeline__year::before {
  content: "";
  display: block;
  width: 18px;
  height: 2px;
  background: var(--lime);
}

.page-about .about-timeline__card {
  margin-top: 8px;
  padding: 14px 16px;
  background: var(--steel);
  border: var(--about-rule);
  border-left: 2px solid var(--board);
}

.page-about .about-timeline__title {
  margin: 0 0 6px;
  font-size: 15px;
  font-weight: 600;
  line-height: 1.5;
  color: var(--fog);
}

.page-about .about-timeline__card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 合作与校验 ---------- */
.page-about .about-partner {
  display: grid;
  gap: 1px;
  margin-top: 24px;
  background: var(--line);
  border: var(--about-rule);
}

.page-about .about-partner__cell {
  background: var(--steel);
  padding: 16px 14px;
  min-width: 0;
}

.page-about .about-partner__k {
  display: block;
  font-size: 1.6rem;
  font-weight: 700;
  line-height: 1;
  color: var(--lime);
}

.page-about .about-partner__v {
  margin: 8px 0 0;
  font-size: 13px;
  line-height: 1.65;
  color: var(--mist);
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 22px;
}

.page-about .about-cta__note {
  margin: 16px 0 0;
  font-size: 13.5px;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-inline-link {
  color: var(--fog);
  text-decoration: none;
  border-bottom: 1px solid var(--orange);
  padding-bottom: 1px;
}

.page-about .about-inline-link:hover,
.page-about .about-inline-link:focus-visible {
  color: var(--orange);
}

/* ---------- 断点 ---------- */
@media (min-width: 620px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .about-partner {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .about-columns {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 760px) {
  .page-about .about-chapter {
    grid-template-columns: minmax(0, 168px) minmax(0, 1fr);
    gap: clamp(20px, 3.4vw, 40px);
  }
  .page-about .about-chapter__aside {
    position: sticky;
    top: calc(var(--topbar-h) + 20px);
    align-self: start;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr);
  }
}

@media (min-width: 1080px) {
  .page-about .about-body {
    grid-template-columns: 148px minmax(0, 1fr);
    align-items: start;
    gap: clamp(32px, 4vw, 56px);
  }
  .page-about .about-toc {
    position: sticky;
    top: calc(var(--topbar-h) + 24px);
  }
  .page-about .about-toc__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 2px;
  }
  .page-about .about-toc__link {
    width: 100%;
    border-color: transparent;
    border-left: 2px solid var(--line);
    background: transparent;
    padding: 8px 10px;
  }
  .page-about .about-toc__link:hover,
  .page-about .about-toc__link:focus-visible {
    border-left-color: var(--orange);
    background: var(--steel);
  }
  .page-about .about-chapter {
    grid-template-columns: minmax(0, 210px) minmax(0, 1fr);
    gap: clamp(28px, 4vw, 56px);
  }
  .page-about .about-columns {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1180px) {
  .page-about .about-columns {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .about-col__summary {
    grid-template-columns: 1fr 22px;
    grid-template-areas:
      "idx plus"
      "name plus"
      "hint plus";
    gap: 4px 8px;
  }
  .page-about .about-col__body {
    padding-left: 16px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc__link,
  .page-about .about-col,
  .page-about .about-col__summary::after {
    transition: none;
  }
}
<<<END>>>