.page-about {
  --about-rail-w: 150px;
  --about-gap: clamp(20px, 3vw, 44px);
}

.page-about .about-crumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: clamp(18px, 3vw, 28px) 0 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--fg-dim);
}

.page-about .about-crumb__sep {
  color: var(--ink-700);
}

.page-about .about-crumb .sk-breadcrumb__item[aria-current="page"] {
  color: var(--lime);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(26px, 5vw, 56px) 0 clamp(40px, 7vw, 88px);
  border-bottom: var(--border);
  background:
    radial-gradient(120% 90% at 88% 8%, rgba(200, 255, 61, .13) 0%, rgba(200, 255, 61, 0) 58%),
    repeating-linear-gradient(90deg, rgba(243, 247, 234, .045) 0 1px, transparent 1px 92px),
    repeating-linear-gradient(0deg, rgba(243, 247, 234, .035) 0 1px, transparent 1px 92px),
    var(--bg);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 4vw, 48px);
  align-items: start;
}

.page-about .about-hero__title {
  margin: 16px 0 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(38px, 10.5vw, 96px);
  line-height: .96;
  letter-spacing: -.01em;
  color: var(--fg);
  text-wrap: balance;
}

.page-about .about-hero__mark {
  position: relative;
  color: var(--lime);
  font-weight: 600;
  white-space: nowrap;
}

.page-about .about-hero__mark::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -.08em;
  height: 4px;
  background: var(--lime);
  opacity: .55;
}

.page-about .about-hero__text {
  max-width: 54ch;
  margin: 22px 0 0;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.85;
  color: var(--mute);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

/* 概况浮岛 */
.page-about .about-figures {
  position: relative;
  border: var(--border);
  border-radius: var(--r-md);
  background: var(--ink-900);
  box-shadow: var(--shadow-hard);
  padding: 20px clamp(16px, 2.4vw, 24px) 8px;
}

.page-about .about-figures::before {
  content: "";
  position: absolute;
  top: -10px;
  right: 22px;
  width: 46px;
  height: 10px;
  background: var(--sand);
}

.page-about .about-figures__eyebrow {
  margin: 0 0 8px;
  color: var(--sand);
}

.page-about .about-figures__list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-figures__item {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px;
  padding: 14px 0;
  border-top: var(--hair);
}

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

.page-about .about-figures__num {
  font-size: clamp(26px, 4.4vw, 34px);
  font-weight: 600;
  line-height: 1;
  color: var(--lime);
}

.page-about .about-figures__label {
  font-size: 13px;
  line-height: 1.5;
  color: var(--fg-dim);
  text-align: right;
}

/* ---------- 主体：年份索引 + 章节 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 56px);
  padding-top: clamp(36px, 6vw, 76px);
  padding-bottom: clamp(48px, 8vw, 96px);
}

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

.page-about .about-rail__title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--fg-dim);
}

.page-about .about-rail__list {
  list-style: none;
  display: flex;
  gap: 10px;
  margin: 0;
  padding: 0 0 6px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-rail__link {
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 0 0 auto;
  padding: 10px 14px;
  border: var(--border);
  border-radius: var(--r-sm);
  background: var(--ink-900);
  color: var(--fg);
  font-family: var(--font-mono);
  font-size: 15px;
  text-decoration: none;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .about-rail__link em {
  font-style: normal;
  font-family: var(--font-body);
  font-size: 11px;
  letter-spacing: .04em;
  color: var(--fg-dim);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  border-color: var(--lime);
  background: var(--ink-800);
  transform: translateX(2px);
  outline: none;
}

.page-about .about-rail__link:hover em,
.page-about .about-rail__link:focus-visible em {
  color: var(--lime);
}

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

/* 章节 */
.page-about .about-chapter {
  padding: clamp(26px, 4vw, 44px) 0 clamp(30px, 5vw, 54px);
  border-top: var(--hair);
}

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

.page-about .about-chapter__head {
  display: flex;
  align-items: flex-start;
  gap: clamp(12px, 2vw, 22px);
}

.page-about .about-chapter__num {
  flex: 0 0 auto;
  font-size: clamp(38px, 6vw, 60px);
  font-weight: 700;
  line-height: .85;
  color: var(--ink-700);
  -webkit-text-stroke: 1px var(--ink-700);
}

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

.page-about .about-chapter__title {
  margin: 8px 0 0;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(24px, 4.2vw, 40px);
  line-height: 1.16;
  letter-spacing: -.005em;
  color: var(--fg);
}

.page-about .about-chapter__text {
  max-width: 68ch;
  margin: 20px 0 0;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.85;
  color: var(--mute);
}

.page-about .about-chapter__note {
  max-width: 68ch;
  margin: 24px 0 0;
  padding: 14px 18px;
  border-left: 3px solid var(--sand);
  background: var(--ink-900);
  font-size: 14px;
  line-height: 1.75;
  color: var(--fg-dim);
}

/* 图片 */
.page-about .about-figure {
  margin: 28px 0 0;
  border: var(--border);
  border-radius: var(--r-sm);
  overflow: hidden;
  background: var(--ink-900);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  aspect-ratio: 16 / 9;
}

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

.page-about .about-figure--wide img {
  aspect-ratio: 7 / 5;
}

.page-about .about-figure__caption {
  padding: 12px 16px;
  border-top: var(--hair);
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.7;
  letter-spacing: .04em;
  color: var(--fg-dim);
}

/* 时间轴 */
.page-about .about-timeline {
  position: relative;
  margin-top: 26px;
  padding-bottom: 10px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-timeline__track {
  display: flex;
  gap: 0;
  list-style: none;
  margin: 0;
  padding: 0;
  width: max-content;
}

.page-about .about-node {
  position: relative;
  flex: 0 0 auto;
  width: min(74vw, 280px);
  padding: 30px 20px 22px 0;
  border-top: 2px solid var(--ink-700);
  margin-right: 18px;
  scroll-snap-align: start;
}

.page-about .about-node::before {
  content: "";
  position: absolute;
  top: -8px;
  left: 0;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--sand);
  border: 2px solid var(--bg);
}

.page-about .about-node__year {
  display: block;
  font-size: clamp(22px, 3vw, 28px);
  font-weight: 600;
  color: var(--lime);
}

.page-about .about-node .sk-tag {
  margin-top: 10px;
}

.page-about .about-node__title {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 19px;
  line-height: 1.35;
  color: var(--fg);
}

.page-about .about-node__text {
  margin: 10px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--fg-dim);
}

/* 三步流程 */
.page-about .about-steps {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  border: var(--border);
  border-radius: var(--r-md);
  overflow: hidden;
  background: var(--ink-900);
}

.page-about .about-step {
  padding: 22px 20px 24px;
  border-top: var(--hair);
  transition: background var(--dur) var(--ease);
}

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

.page-about .about-step:hover {
  background: var(--ink-800);
}

.page-about .about-step__num {
  display: block;
  font-size: 30px;
  font-weight: 600;
  line-height: 1;
  color: var(--sand);
}

.page-about .about-step__title {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 20px;
  letter-spacing: .02em;
  color: var(--fg);
}

.page-about .about-step__text {
  margin: 10px 0 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--mute);
}

.page-about .about-step__note {
  margin: 14px 0 0;
  padding-top: 12px;
  border-top: var(--hair);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.7;
  color: var(--fg-dim);
  transition: color var(--dur) var(--ease);
}

.page-about .about-step:hover .about-step__note {
  color: var(--mint);
}

/* 版本演进列表 */
.page-about .about-milestones {
  margin: 26px 0 0;
  padding: 0;
  border-top: var(--hair);
}

.page-about .about-milestone {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
  padding: 18px 0;
  border-bottom: var(--hair);
}

.page-about .about-milestone__key {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 17px;
  letter-spacing: .01em;
  color: var(--fg);
}

.page-about .about-milestone__tag {
  font-family: var(--font-mono);
  font-size: 10.5px;
}

.page-about .about-milestone__val {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--mute);
}

/* 服务对照矩阵 */
.page-about .about-chapter--sand {
  margin-top: clamp(16px, 2.5vw, 28px);
  padding: clamp(26px, 4vw, 44px) clamp(18px, 3vw, 32px);
  border: var(--border);
  border-radius: var(--r-md);
  background: linear-gradient(160deg, var(--ink-900) 0%, #0a231a 100%);
  box-shadow: var(--shadow-hard);
}

.page-about .about-matrix {
  margin-top: 24px;
  border-top: 2px solid var(--sand);
}

.page-about .about-matrix__head {
  display: none;
}

.page-about .about-matrix__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 16px 0;
  border-bottom: var(--hair);
}

.page-about .about-matrix__name {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 18px;
  color: var(--lime);
}

.page-about .about-matrix__who {
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--fg-dim);
}

.page-about .about-matrix__how {
  font-size: 14px;
  line-height: 1.75;
  color: var(--fg);
}

/* 规模数据 */
.page-about .about-stats {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 26px 0 0;
  padding: 1px;
  background: var(--ink-700);
  border-radius: var(--r-sm);
  overflow: hidden;
}

.page-about .about-stats__item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 14px;
  background: var(--ink-900);
}

.page-about .about-stats__num {
  font-size: clamp(26px, 4vw, 34px);
  font-weight: 600;
  line-height: 1;
  color: var(--mint);
}

.page-about .about-stats__label {
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--fg-dim);
}

/* 下一步 */
.page-about .about-next {
  margin-top: 28px;
  padding: clamp(20px, 3vw, 28px);
  border: 2px solid var(--lime);
  border-radius: var(--r-md);
  background: rgba(200, 255, 61, .06);
}

.page-about .about-next__eyebrow {
  margin: 0;
  color: var(--lime);
}

.page-about .about-next__text {
  max-width: 56ch;
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--fg);
}

.page-about .about-next__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 20px;
}

/* ---------- 断点 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, .85fr);
    align-items: end;
  }

  .page-about .about-figures {
    margin-top: 8px;
  }

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

  .page-about .about-step {
    border-top: 0;
    border-left: var(--hair);
  }

  .page-about .about-step:first-child {
    border-left: 0;
  }

  .page-about .about-milestone {
    grid-template-columns: minmax(0, .75fr) minmax(0, 1.25fr);
    gap: 24px;
    align-items: start;
  }

  .page-about .about-matrix__head {
    display: grid;
    grid-template-columns: minmax(0, .8fr) minmax(0, 1fr) minmax(0, 1.3fr);
    gap: 20px;
    padding: 10px 0;
    border-bottom: var(--hair);
    font-family: var(--font-mono);
    font-size: 10.5px;
    letter-spacing: .14em;
    text-transform: uppercase;
    color: var(--sand);
  }

  .page-about .about-matrix__row {
    grid-template-columns: minmax(0, .8fr) minmax(0, 1fr) minmax(0, 1.3fr);
    gap: 20px;
    align-items: start;
  }

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

@media (min-width: 1024px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: var(--about-gap);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: 104px;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    gap: 8px;
    overflow: visible;
  }

  .page-about .about-rail__link {
    width: 100%;
    padding: 10px 12px;
  }

  .page-about .about-chapter__num {
    -webkit-text-stroke: 0;
    color: var(--ink-800);
  }

  .page-about .about-figure--inset {
    max-width: 620px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__link,
  .page-about .about-step,
  .page-about .about-step__note {
    transition: none;
  }
}
<<<END>>>