.page-about {
  --about-trail: 5.5px;
  --about-glow: rgba(79, 163, 165, .16);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  padding: clamp(2.5rem, 7vw, 5.5rem) 0 clamp(1.75rem, 4vw, 3rem);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--line) 18%, var(--line) 82%, transparent);
  opacity: .7;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: -6rem;
  right: -8rem;
  width: min(38rem, 78vw);
  aspect-ratio: 1;
  background: radial-gradient(circle at 50% 50%, var(--about-glow), transparent 68%);
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__title {
  font-family: var(--font-serif);
  font-weight: 800;
  font-size: clamp(2rem, 6.6vw, 4.2rem);
  line-height: 1.14;
  letter-spacing: .008em;
  margin: .9rem 0 0;
  color: var(--ink);
  max-width: 17em;
}

.page-about .about-hero__lede {
  margin: 1.25rem 0 0;
  max-width: 36em;
  font-size: clamp(1rem, 1.6vw, 1.125rem);
  line-height: 1.95;
  color: var(--ink);
  opacity: .88;
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(1.75rem, 4vw, 2.75rem) 0 0;
  padding: 1px;
  background: var(--line);
  border-radius: 3px;
  overflow: hidden;
}

.page-about .about-fact {
  background: var(--indigo-850);
  padding: .85rem 1rem .95rem;
}

.page-about .about-fact__k {
  font-size: .72rem;
  letter-spacing: .16em;
  color: var(--muted);
  line-height: 1.4;
}

.page-about .about-fact__v {
  margin: .4rem 0 0;
  font-size: 1.05rem;
  color: var(--gold-soft);
  letter-spacing: .02em;
}

/* ---------- 面包屑 ---------- */

.page-about .breadcrumbs {
  padding: .25rem 0 clamp(1.25rem, 3vw, 2rem);
}

/* ---------- 左窄右宽骨架 ---------- */

.page-about .about-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(2rem, 5vw, 3rem);
  padding-bottom: clamp(3rem, 9vw, 6.5rem);
}

.page-about .about-rail {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.page-about .about-rail__label {
  margin: 0;
  font-size: .72rem;
  letter-spacing: .2em;
  color: var(--muted);
}

.page-about .about-toc {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 1px solid var(--line);
}

.page-about .about-toc a {
  display: block;
  position: relative;
  padding: .5rem .25rem .5rem 1.35rem;
  font-size: .875rem;
  line-height: 1.6;
  color: var(--muted);
  text-decoration: none;
  transition: color .22s var(--ease);
}

.page-about .about-toc a::before {
  content: "";
  position: absolute;
  left: -1px;
  top: 50%;
  width: 9px;
  height: 1px;
  background: var(--line);
  transition: background .22s var(--ease), width .22s var(--ease);
}

.page-about .about-toc a:hover,
.page-about .about-toc a:focus-visible {
  color: var(--gold-soft);
}

.page-about .about-toc a:hover::before,
.page-about .about-toc a:focus-visible::before {
  width: 15px;
  background: var(--coral);
}

.page-about .about-status {
  display: flex;
  gap: .6rem;
  align-items: flex-start;
  padding: .9rem 1rem;
  border: 1px solid var(--line);
  border-left: 2px solid var(--teal);
  border-radius: 2px;
  background: var(--indigo-850);
}

.page-about .about-status__text {
  margin: 0;
  font-size: .82rem;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 正文区 ---------- */

.page-about .about-body {
  position: relative;
  min-width: 0;
}

.page-about .about-body::before {
  content: "";
  position: absolute;
  top: 3rem;
  right: -4rem;
  width: 12rem;
  height: 72%;
  background: linear-gradient(180deg, rgba(79, 163, 165, .13), rgba(227, 178, 91, .07) 42%, transparent 82%);
  pointer-events: none;
  z-index: 0;
}

.page-about .about-body > * {
  position: relative;
  z-index: 1;
}

.page-about .about-chapter {
  padding-block: clamp(2rem, 5vw, 3.5rem);
  border-top: 1px solid var(--line);
}

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

.page-about .about-chapter__head {
  display: flex;
  align-items: baseline;
  gap: .9rem;
  margin-bottom: clamp(1rem, 2.5vw, 1.6rem);
}

.page-about .about-chapter__no {
  flex: none;
  font-size: .78rem;
  letter-spacing: .14em;
  color: var(--coral);
  padding-top: .3rem;
}

.page-about .about-chapter__title {
  font-family: var(--font-serif);
  font-weight: 800;
  font-size: clamp(1.45rem, 3.6vw, 2.25rem);
  line-height: 1.3;
  margin: 0;
  color: var(--ink);
  letter-spacing: .01em;
}

.page-about .about-copy {
  max-width: 38em;
}

.page-about .about-copy p {
  margin: 0 0 1.1rem;
  font-size: 1rem;
  line-height: 1.95;
  color: var(--ink);
  opacity: .86;
}

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

/* ---------- 通栏图片 ---------- */

.page-about .about-plate {
  margin: clamp(1.25rem, 3vw, 2rem) 0;
  border-radius: 3px;
}

.page-about .about-plate img,
.page-about .about-portrait img {
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 时间线折叠组 ---------- */

.page-about .timeline {
  position: relative;
  margin: clamp(1.5rem, 4vw, 2.5rem) 0 clamp(1.5rem, 4vw, 2.25rem);
  padding: 0;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: var(--about-trail);
  top: 1.4rem;
  bottom: 1.4rem;
  width: 1px;
  background: linear-gradient(to bottom, var(--gold) 0%, var(--coral) 46%, var(--line) 100%);
}

.page-about .timeline__item {
  position: relative;
  padding-left: 1.9rem;
}

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 1.15rem;
  width: 11px;
  height: 11px;
  background: var(--indigo-850);
  border: 1px solid var(--gold);
  clip-path: polygon(0 0, 100% 0, 100% 62%, 62% 100%, 0 100%);
  transition: border-color .22s var(--ease), background .22s var(--ease);
}

.page-about .timeline__item:hover::before {
  border-color: var(--coral);
}

.page-about .timeline__button {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: baseline;
  gap: .35rem .85rem;
  width: 100%;
  padding: .85rem 0;
  background: none;
  border: 0;
  color: inherit;
  font: inherit;
  text-align: left;
  cursor: pointer;
  transition: color .2s var(--ease);
}

.page-about .timeline__button:focus-visible {
  outline: 1px solid var(--gold);
  outline-offset: 4px;
}

.page-about .timeline__no {
  font-size: .74rem;
  letter-spacing: .12em;
  color: var(--muted);
}

.page-about .timeline__head {
  display: flex;
  flex-direction: column;
  gap: .22rem;
  min-width: 0;
}

.page-about .timeline__stage {
  font-size: .74rem;
  letter-spacing: .16em;
  color: var(--teal);
}

.page-about .timeline__title {
  font-family: var(--font-serif);
  font-weight: 800;
  font-size: clamp(1.02rem, 2.2vw, 1.22rem);
  line-height: 1.5;
  color: var(--ink);
}

.page-about .timeline__button[aria-expanded="true"] .timeline__title {
  color: var(--gold-soft);
}

.page-about .timeline__panel {
  padding: 0 0 1rem;
  border-bottom: 1px solid var(--line);
}

.page-about .timeline__panel .about-copy p {
  font-size: .95rem;
  color: var(--muted);
  opacity: 1;
}

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

/* ---------- 团队分工 ---------- */

.page-about .about-roles {
  list-style: none;
  margin: clamp(1.25rem, 3vw, 1.9rem) 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: 3px;
  overflow: hidden;
}

.page-about .about-role {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 1.05rem 1.1rem;
  background: var(--indigo-850);
}

.page-about .about-role__n {
  flex: none;
  min-width: 2.2em;
  font-size: 1.35rem;
  line-height: 1.2;
  color: var(--gold);
  text-align: right;
}

.page-about .about-role__b {
  display: flex;
  flex-direction: column;
  gap: .3rem;
  min-width: 0;
}

.page-about .about-role__t {
  font-size: .98rem;
  line-height: 1.5;
  color: var(--ink);
}

.page-about .about-role__d {
  font-size: .86rem;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 结尾 ---------- */

.page-about .about-closing {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.25rem, 3vw, 2rem);
  margin-top: clamp(1.5rem, 4vw, 2.25rem);
  padding-top: clamp(1.5rem, 4vw, 2.25rem);
  border-top: 1px solid var(--line);
}

.page-about .about-closing__line {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 800;
  font-size: clamp(1.05rem, 2.4vw, 1.4rem);
  line-height: 1.85;
  color: var(--ink);
  max-width: 26em;
}

.page-about .about-portrait {
  width: 100%;
  max-width: 22rem;
  border-radius: 3px;
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-toc {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    border-left: 0;
    border-top: 1px solid var(--line);
  }

  .page-about .about-toc a::before {
    left: 0;
    top: 0;
    width: 1px;
    height: 100%;
    background: transparent;
  }

  .page-about .about-toc a {
    border-left: 1px solid var(--line);
    padding: .6rem .5rem .6rem 1rem;
  }
}

@media (min-width: 960px) {
  .page-about .about-grid {
    grid-template-columns: 220px minmax(0, 1fr);
    gap: clamp(2.5rem, 6vw, 5.5rem);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: 7rem;
  }

  .page-about .about-toc {
    display: block;
    grid-template-columns: none;
    border-top: 0;
    border-left: 1px solid var(--line);
  }

  .page-about .about-toc a {
    border-left: 0;
    padding: .5rem .25rem .5rem 1.35rem;
  }

  .page-about .about-toc a::before {
    left: -1px;
    top: 50%;
    width: 9px;
    height: 1px;
    background: var(--line);
  }

  .page-about .about-toc a:hover::before,
  .page-about .about-toc a:focus-visible::before {
    width: 15px;
    background: var(--coral);
  }

  .page-about .about-closing {
    grid-template-columns: minmax(0, 1fr) 20rem;
    align-items: center;
  }

  .page-about .about-role {
    align-items: center;
    padding: 1.25rem 1.35rem;
  }

  .page-about .about-role__n {
    font-size: 1.75rem;
  }
}

@media (min-width: 1200px) {
  .page-about .about-grid {
    grid-template-columns: 240px minmax(0, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc a,
  .page-about .about-toc a::before,
  .page-about .timeline__item::before,
  .page-about .timeline__button {
    transition: none;
  }
}
<<<END>>>