.page-about {
  --about-axis-w: 216px;
  --about-gap: clamp(28px, 4vw, 64px);
  --about-text: #C9DCD6;
  --about-glass: rgba(10, 26, 22, .74);
  background: var(--ink-950);
  color: var(--paper-050);
}

.page-about a:focus-visible {
  outline: 2px solid var(--focus-500);
  outline-offset: 3px;
}

.page-about .frame__bar {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 8px 16px;
  padding: 10px clamp(16px, 3vw, 28px);
  border-bottom: var(--line);
  font-size: 12px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--muted-400);
}

.page-about .media-frame {
  position: relative;
  overflow: hidden;
  border: var(--line);
  background: var(--ink-900);
}

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

/* ---------- 阅读进度细线 ---------- */

.about-progress {
  position: fixed;
  inset: 0 auto 0 0;
  width: 3px;
  background: linear-gradient(180deg, var(--cyan-500) 0%, var(--amber-600) 100%);
  transform: scaleY(var(--progress, 0));
  transform-origin: top center;
  z-index: 40;
  pointer-events: none;
  opacity: .9;
}

/* ---------- 框景首屏 ---------- */

.about-hero {
  max-width: var(--shell-w);
  margin: 0 auto;
  padding: clamp(20px, 4vw, 44px) var(--gutter) 0;
}

.about-hero__frame {
  position: relative;
  border: var(--line);
  background:
    radial-gradient(120% 140% at 10% 0%, rgba(47, 230, 196, .12), transparent 58%),
    linear-gradient(155deg, var(--ink-900) 0%, var(--ink-950) 74%);
}

.about-hero__frame::before,
.about-hero__frame::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  height: 6px;
  background-image: repeating-linear-gradient(90deg, var(--line-700) 0 1px, transparent 1px 16px);
  pointer-events: none;
}

.about-hero__frame::before { top: 5px; }
.about-hero__frame::after { bottom: 5px; }

.about-hero__body {
  display: grid;
  gap: 20px;
  padding: clamp(26px, 5vw, 60px);
}

.page-about .breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 14px;
  font-size: 13px;
}

.page-about .breadcrumbs__item {
  color: var(--muted-400);
  text-decoration: none;
}

.page-about .breadcrumbs__item + .breadcrumbs__item::before {
  content: "/";
  margin-right: 14px;
  color: var(--line-700);
}

.page-about a.breadcrumbs__item:hover,
.page-about a.breadcrumbs__item:focus-visible {
  color: var(--cyan-300);
}

.page-about .breadcrumbs__item[aria-current="page"] {
  color: var(--paper-050);
}

.about-hero h1 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(36px, 8vw, 74px);
  line-height: 1.02;
  letter-spacing: -0.015em;
  max-width: 17ch;
}

.about-hero__lede {
  margin: 0;
  max-width: 60ch;
  color: var(--about-text);
  font-size: clamp(16px, 1.4vw, 18px);
  line-height: 1.78;
}

.about-hero__stats {
  display: grid;
  gap: 0;
  margin: 6px 0 0;
  padding: 0;
  list-style: none;
  border-top: var(--line);
}

.about-hero__stats li {
  display: grid;
  gap: 4px;
  padding: 16px 0 0;
}

.about-hero__num {
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--cyan-500);
}

.about-hero__label {
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted-400);
}

/* ---------- 层叠目录骨架 ---------- */

.about-layout {
  max-width: var(--shell-w);
  margin: 0 auto;
  padding: clamp(48px, 8vw, 104px) var(--gutter) clamp(48px, 6vw, 88px);
  display: grid;
  gap: var(--about-gap);
}

.about-axis__title {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--muted-400);
}

.about-axis__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 1px solid var(--line-700);
}

.about-axis__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  min-height: 44px;
  padding: 10px 12px;
  margin-left: -1px;
  border-left: 2px solid transparent;
  color: var(--muted-400);
  font-size: 14px;
  text-decoration: none;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

.about-axis__link .mono {
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--amber-400);
}

.about-axis__link:hover,
.about-axis__link:focus-visible {
  color: var(--cyan-300);
  border-left-color: var(--cyan-500);
}

/* ---------- 章节 ---------- */

.about-section {
  padding-bottom: clamp(48px, 7vw, 88px);
}

.about-section + .about-section {
  border-top: var(--line);
  padding-top: clamp(40px, 6vw, 76px);
}

.about-section__index {
  margin: 0 0 12px;
  font-size: 12px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--amber-400);
}

.about-section h2 {
  margin: 0 0 18px;
  font-family: var(--font-editorial);
  font-weight: 600;
  font-size: clamp(25px, 3.4vw, 38px);
  line-height: 1.28;
  letter-spacing: -0.01em;
}

.about-intro,
.about-prose p,
.about-network__text p {
  margin: 0 0 16px;
  max-width: 68ch;
  color: var(--about-text);
  font-size: clamp(15.5px, 1.2vw, 17px);
  line-height: 1.78;
}

.about-prose p:last-child,
.about-network__text p:last-child {
  margin-bottom: 0;
}

/* ---------- 通栏图片 ---------- */

.about-wide {
  margin: clamp(28px, 4vw, 46px) 0 0;
}

.about-wide--offset {
  margin-left: clamp(0px, 4vw, 56px);
}

.about-caption {
  margin: 12px 0 0;
  max-width: 60ch;
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted-400);
}

/* ---------- 分工表 ---------- */

.about-roles {
  margin-top: 28px;
  border-top: var(--line);
}

.about-role {
  display: grid;
  gap: 8px;
  padding: 22px 12px;
  border-bottom: var(--line);
  transition: background-color .18s var(--ease), box-shadow .18s var(--ease);
}

.about-role__name {
  margin: 0;
  font-family: var(--font-editorial);
  font-size: 18px;
  font-weight: 600;
  color: var(--cyan-300);
}

.about-role__desc {
  margin: 0;
  max-width: 66ch;
  color: var(--about-text);
  font-size: 15.5px;
  line-height: 1.75;
}

@media (hover: hover) {
  .about-role:hover,
  .about-role:focus-within {
    background: rgba(47, 230, 196, .06);
    box-shadow: inset 3px 0 0 var(--cyan-500);
  }
}

/* ---------- 引用块 ---------- */

.about-quote {
  margin: clamp(28px, 4vw, 42px) 0 0;
  padding: 20px 22px;
  border-left: 3px solid var(--cyan-500);
  background: var(--about-glass);
  backdrop-filter: blur(14px) saturate(140%);
  font-family: var(--font-editorial);
  font-size: clamp(17px, 2vw, 20px);
  line-height: 1.7;
  color: var(--paper-050);
}

/* ---------- 阶段进度轴 ---------- */

.about-stages-grid {
  display: grid;
  gap: clamp(28px, 4vw, 48px);
  margin-top: 28px;
}

.about-stages {
  display: grid;
  gap: 24px;
}

.about-stage {
  padding: 4px 0 4px 20px;
  border-left: 2px solid var(--line-700);
  scroll-margin-top: calc(var(--header-h) + 32px);
  transition: border-color .2s var(--ease), background-color .2s var(--ease);
}

.about-stage:target {
  border-left-color: var(--cyan-500);
  background: linear-gradient(90deg, rgba(47, 230, 196, .12), transparent 72%);
}

.about-stage__no {
  display: block;
  font-size: 12px;
  letter-spacing: .2em;
  color: var(--amber-400);
}

.about-stage__title {
  margin: 6px 0 8px;
  font-family: var(--font-editorial);
  font-size: 19px;
  font-weight: 600;
  line-height: 1.4;
}

.about-stage p {
  margin: 0;
  max-width: 62ch;
  color: var(--about-text);
  font-size: 15.5px;
  line-height: 1.78;
}

.about-stages-media {
  margin: 0;
}

/* ---------- 合作生态 ---------- */

.about-network {
  display: grid;
  gap: clamp(20px, 3vw, 40px);
  align-items: start;
  margin-top: 6px;
}

.about-network__figure {
  display: grid;
  gap: 6px;
}

.about-network__num {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(64px, 13vw, 112px);
  line-height: .88;
  letter-spacing: -0.03em;
  color: var(--cyan-500);
}

.about-network__unit {
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted-400);
}

.about-network__text p {
  margin-bottom: 16px;
}

/* ---------- 内容线 ---------- */

.about-lines {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  border-top: var(--line);
}

.about-line {
  display: grid;
  gap: 6px;
  padding: 20px 0;
  border-bottom: var(--line);
}

.about-line__name {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 22px;
  letter-spacing: .04em;
  color: var(--amber-400);
}

.about-line p {
  margin: 0;
  max-width: 64ch;
  color: var(--about-text);
  font-size: 15.5px;
  line-height: 1.75;
}

/* ---------- 延伸入口 ---------- */

.about-next {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.about-next__link {
  display: grid;
  gap: 6px;
  min-height: 44px;
  padding: 20px 22px;
  border: var(--line);
  background: var(--ink-900);
  color: inherit;
  text-decoration: none;
  transition: border-color .18s var(--ease), background-color .18s var(--ease), transform .18s var(--ease);
}

.about-next__link:hover,
.about-next__link:focus-visible {
  border-color: var(--cyan-500);
  background: var(--ink-800);
  transform: translateX(6px);
}

.about-next__name {
  font-family: var(--font-editorial);
  font-size: 19px;
  font-weight: 600;
  color: var(--paper-050);
}

.about-next__desc {
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--muted-400);
}

/* ---------- 平板及以上 ---------- */

@media (min-width: 640px) {
  .about-hero__stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1px;
  }

  .about-hero__stats li {
    padding: 18px 0 0;
  }

  .about-hero__stats li + li {
    border-left: var(--line);
    padding-left: 22px;
  }
}

@media (min-width: 760px) {
  .about-role:nth-child(even) {
    margin-left: 32px;
  }

  .about-line {
    grid-template-columns: 128px minmax(0, 1fr);
    gap: 26px;
    align-items: baseline;
  }

  .about-line:nth-child(even) {
    margin-left: 30px;
  }

  .about-next__item:nth-child(even) {
    margin-left: 40px;
  }
}

@media (min-width: 900px) {
  .about-stages-grid {
    grid-template-columns: minmax(0, 1fr) 258px;
    align-items: start;
  }

  .about-stages-media {
    position: sticky;
    top: calc(var(--header-h) + 28px);
  }

  .about-network {
    grid-template-columns: 208px minmax(0, 1fr);
  }
}

@media (min-width: 940px) {
  .about-layout {
    grid-template-columns: var(--about-axis-w) minmax(0, 1fr);
    align-items: start;
  }

  .about-axis {
    position: sticky;
    top: calc(var(--header-h) + 28px);
  }
}

@media (min-width: 1100px) {
  .about-hero__body {
    grid-template-columns: minmax(0, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  .about-stage,
  .about-role,
  .about-axis__link,
  .about-next__link {
    transition: none;
  }

  .about-next__link:hover,
  .about-next__link:focus-visible {
    transform: none;
  }
}
<<<END>>>

.page-about {
  --progress: inherit;
}