.page-about {
  --about-dim: rgba(242, 245, 242, 0.07);
  --about-cardbg: var(--graphite);
  background: var(--ink);
  color: var(--paper);
  overflow-x: hidden;
}

.page-about .about-crumbs {
  padding-top: calc(var(--header-h) + 26px);
}

.page-about .about-hero {
  padding-top: clamp(26px, 5vw, 54px);
  padding-bottom: clamp(38px, 7vw, 84px);
}

.page-about .about-hero__title {
  margin: 16px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(34px, 7vw, 88px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  max-width: 16em;
}

.page-about .about-hero__lede {
  margin: clamp(20px, 3vw, 30px) 0 0;
  font-size: var(--fs-3);
  line-height: 1.8;
  color: var(--paper);
  max-width: 42em;
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(28px, 5vw, 52px) 0 0;
  padding: 1px;
  background: var(--hair);
  border: 1px solid var(--hair);
}

.page-about .about-facts__item {
  background: var(--about-cardbg);
  padding: 16px 18px 18px;
}

.page-about .about-facts dt {
  font-size: var(--fs-1);
  letter-spacing: 0.06em;
  color: var(--mute);
}

.page-about .about-facts dd {
  margin: 8px 0 0;
  font-weight: 700;
  font-size: clamp(20px, 3.4vw, 28px);
  font-variant-numeric: tabular-nums;
  color: var(--lime);
  line-height: 1.1;
}

/* 象牙纸自述块 */
.page-about .about-note {
  background: var(--ivory);
  color: var(--ink);
  padding-block: clamp(40px, 7vw, 84px);
}

.page-about .about-note__grid {
  display: grid;
  gap: clamp(22px, 4vw, 40px);
}

.page-about .about-note__label {
  margin: 0;
  display: inline-block;
  padding-left: 12px;
  border-left: 3px solid var(--lime);
  font-size: var(--fs-1);
  letter-spacing: 0.2em;
  color: #3d4a3f;
}

.page-about .about-note__stamp {
  margin: 14px 0 0;
  font-size: var(--fs-2);
  color: #56604f;
  letter-spacing: 0.02em;
}

.page-about .about-note__title {
  margin: 0 0 clamp(18px, 3vw, 26px);
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(26px, 4.4vw, 46px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .about-note__quote {
  margin: 0 0 clamp(18px, 3vw, 26px);
  padding-left: clamp(14px, 2vw, 22px);
  border-left: 3px solid var(--lime);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(20px, 3.2vw, 30px);
  line-height: 1.55;
  color: #10160f;
}

.page-about .about-note__main p {
  margin: 0 0 16px;
  font-size: var(--fs-3);
  line-height: 1.85;
  color: #22282a;
  max-width: 40em;
}

/* 章节通用 */
.page-about .about-chapter {
  position: relative;
  padding-block: clamp(46px, 7vw, 104px);
  border-top: 1px solid var(--hair);
}

.page-about .about-chapter__num {
  display: block;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(64px, 15vw, 148px);
  line-height: 0.82;
  letter-spacing: -0.05em;
  font-variant-numeric: tabular-nums;
  color: var(--about-dim);
  user-select: none;
}

.page-about .about-chapter__head h2 {
  margin: 6px 0 clamp(20px, 3vw, 28px);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(25px, 4.2vw, 44px);
  line-height: 1.22;
  letter-spacing: -0.01em;
  color: var(--paper);
  max-width: 20em;
}

.page-about .about-chapter__body p {
  margin: 0 0 18px;
  font-size: var(--fs-3);
  line-height: 1.8;
  color: var(--paper);
  max-width: 42em;
}

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

.page-about .about-chapter__body a {
  color: var(--blue);
  text-decoration: none;
  border-bottom: 1px solid rgba(47, 212, 255, 0.45);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-chapter__body a:hover,
.page-about .about-chapter__body a:focus-visible {
  color: var(--lime);
  border-bottom-color: var(--lime);
}

/* 图片容器 */
.page-about .about-figure {
  margin: clamp(26px, 4vw, 40px) 0 0;
  border: 1px solid var(--hair);
  background: var(--about-cardbg);
  overflow: hidden;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  aspect-ratio: 14 / 9;
}

.page-about .about-figure--tall img {
  aspect-ratio: 3 / 4;
}

.page-about .about-figure figcaption {
  padding: 12px 16px 14px;
  font-size: var(--fs-2);
  line-height: 1.6;
  color: var(--mute);
  border-top: 1px solid var(--hair);
}

/* 四段流水线 */
.page-about .about-flow {
  list-style: none;
  counter-reset: flow;
  margin: clamp(24px, 4vw, 36px) 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-flow li {
  counter-increment: flow;
  position: relative;
  background: var(--about-cardbg);
  border-left: 2px solid var(--lime);
  padding: 18px 20px 20px;
}

.page-about .about-flow li::before {
  content: "0" counter(flow);
  display: block;
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: var(--fs-2);
  letter-spacing: 0.14em;
  color: var(--lime);
  margin-bottom: 6px;
}

.page-about .about-flow h3 {
  margin: 0 0 8px;
  font-size: var(--fs-4);
  font-weight: 700;
  line-height: 1.35;
  color: var(--paper);
}

.page-about .about-flow p {
  margin: 0;
  font-size: var(--fs-2);
  line-height: 1.75;
  color: var(--mute);
  max-width: none;
}

/* 数据条 */
.page-about .about-stats {
  display: grid;
  gap: 1px;
  margin: clamp(22px, 3.5vw, 32px) 0 clamp(24px, 4vw, 34px);
  padding: 1px;
  background: var(--hair);
  border: 1px solid var(--hair);
}

.page-about .about-stats__item {
  background: var(--about-cardbg);
  padding: 18px 20px 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .about-stats__k {
  font-size: var(--fs-1);
  letter-spacing: 0.08em;
  color: var(--mute);
}

.page-about .about-stats__v {
  font-weight: 700;
  font-size: clamp(24px, 4vw, 34px);
  line-height: 1.1;
  font-variant-numeric: tabular-nums;
  color: var(--blue);
}

.page-about .about-stats__v--warn {
  color: var(--orange);
}

.page-about .about-stats__n {
  font-size: var(--fs-2);
  color: var(--mute);
  line-height: 1.6;
}

/* 版本时间轴 */
.page-about .about-timeline {
  display: grid;
  gap: clamp(20px, 4vw, 32px);
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .about-rail {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 4px;
  scrollbar-width: thin;
}

.page-about .about-rail a {
  flex: 0 0 auto;
  padding: 8px 14px;
  border: 1px solid var(--hair);
  color: var(--mute);
  text-decoration: none;
  font-size: var(--fs-2);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.06em;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-rail a:hover,
.page-about .about-rail a:focus-visible {
  color: var(--lime);
  border-color: var(--lime);
}

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

.page-about .about-mile {
  border-top: 1px solid var(--hair);
}

.page-about .about-mile:last-of-type {
  border-bottom: 1px solid var(--hair);
}

.page-about .about-mile > summary {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 16px 0;
  cursor: pointer;
  list-style: none;
  transition: color var(--dur) var(--ease);
}

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

.page-about .about-mile > summary::after {
  content: "+";
  margin-left: auto;
  font-size: var(--fs-5);
  line-height: 1;
  color: var(--lime);
}

.page-about .about-mile[open] > summary::after {
  content: "\2013";
}

.page-about .about-mile__year {
  font-weight: 700;
  font-size: var(--fs-4);
  font-variant-numeric: tabular-nums;
  color: var(--blue);
  min-width: 4em;
}

.page-about .about-mile__name {
  font-weight: 700;
  font-size: var(--fs-4);
  color: var(--paper);
  line-height: 1.35;
}

.page-about .about-mile[open] > summary .about-mile__name {
  color: var(--lime);
}

.page-about .about-mile__body {
  padding: 0 0 20px;
}

.page-about .about-mile__body p {
  margin: 0;
  font-size: var(--fs-3);
  line-height: 1.8;
  color: var(--mute);
  max-width: 40em;
}

/* 结尾入口 */
.page-about .about-next {
  border-top: 1px solid var(--hair);
  background: var(--graphite);
  padding-block: clamp(40px, 6vw, 76px);
}

.page-about .about-next__title {
  margin: 0 0 clamp(20px, 3vw, 30px);
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(24px, 4vw, 40px);
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: var(--paper);
  max-width: 18em;
}

.page-about .about-next__links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--hair);
  border: 1px solid var(--hair);
}

.page-about .about-next__links a {
  display: block;
  background: var(--ink);
  padding: 18px 20px;
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-next__links a:hover,
.page-about .about-next__links a:focus-visible {
  border-left-color: var(--lime);
  background: var(--steel);
}

.page-about .about-next__links span {
  display: block;
  font-weight: 700;
  font-size: var(--fs-4);
  color: var(--paper);
}

.page-about .about-next__links em {
  display: block;
  margin-top: 6px;
  font-style: normal;
  font-size: var(--fs-2);
  line-height: 1.6;
  color: var(--mute);
}

/* 中屏 */
@media (min-width: 700px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-flow {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1px;
    padding: 1px;
    background: var(--hair);
    border: 1px solid var(--hair);
  }

  .page-about .about-flow li {
    border-left: 2px solid var(--lime);
  }

  .page-about .about-stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-next__links {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* 桌面：出版式双栏与粘性年份轴 */
@media (min-width: 900px) {
  .page-about .about-note__grid {
    grid-template-columns: 220px minmax(0, 1fr);
    gap: 56px;
  }

  .page-about .about-chapter__num {
    font-size: clamp(110px, 13vw, 168px);
    margin-bottom: -18px;
  }

  .page-about .about-chapter__body {
    padding-left: clamp(0px, 4vw, 56px);
  }

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

  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-timeline {
    grid-template-columns: 168px minmax(0, 1fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 36px);
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding-bottom: 0;
    border-left: 1px solid var(--hair);
  }

  .page-about .about-rail a {
    border: 0;
    border-left: 2px solid transparent;
    margin-left: -1px;
    padding: 12px 0 12px 18px;
    font-size: var(--fs-3);
  }

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

  .page-about .about-mile > summary {
    padding: 20px 0;
  }

  .page-about .about-mile__year {
    min-width: 5em;
  }

  .page-about .about-figure--tall {
    max-width: 520px;
  }
}

@media (min-width: 1200px) {
  .page-about .about-hero__title {
    max-width: 14em;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-chapter__body a,
  .page-about .about-rail a,
  .page-about .about-mile > summary,
  .page-about .about-next__links a {
    transition: none;
  }
}
<<<END>>>