.page-about {
  --about-rail-top: 22px;
  --about-shell-w: 200px;
  --about-shell-gap: 72px;
  --about-body-w: 640px;
  color: var(--yx-ink);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-block: 56px 40px;
  position: relative;
  isolation: isolate;
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: -20% -10% auto auto;
  width: 520px;
  height: 520px;
  background: radial-gradient(circle at 50% 50%, rgba(15, 163, 160, 0.28), rgba(15, 163, 160, 0) 68%);
  z-index: -1;
  pointer-events: none;
}

.page-about .about-hero__crumbs {
  margin-bottom: 24px;
}

.page-about .about-hero__eyebrow {
  color: var(--yx-lake-soft);
  letter-spacing: 0.16em;
}

.page-about .about-hero__title {
  margin: 12px 0 0;
  max-width: 15ch;
}

.page-about .about-hero__lede {
  margin-top: 20px;
  max-width: 62ch;
  color: rgba(245, 247, 246, 0.82);
}

.page-about .about-numbers {
  list-style: none;
  margin: 40px 0 0;
  padding: 24px 0 0;
  border-top: 1px solid var(--yx-line-dark);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px 16px;
}

.page-about .about-numbers__item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 0;
}

.page-about .about-numbers__val {
  font-size: 34px;
  line-height: 1;
  font-weight: 700;
  color: var(--yx-lime);
  letter-spacing: -0.01em;
}

.page-about .about-numbers__val em {
  font-style: normal;
  font-size: 16px;
  margin-left: 3px;
  color: var(--yx-lake-soft);
}

.page-about .about-numbers__key {
  font-size: 13px;
  color: rgba(245, 247, 246, 0.62);
  letter-spacing: 0.04em;
}

/* ---------- 首屏下方宽幅图 ---------- */
.page-about .about-banner {
  background: var(--yx-night);
  padding-block: 0 56px;
}

.page-about .about-banner__media {
  margin: 0;
  border: 1px solid var(--yx-line-dark);
  border-radius: var(--yx-radius-lg);
  overflow: hidden;
  background: var(--yx-night-2);
}

/* ---------- 章节条 ---------- */
.page-about .about-jump {
  padding-block: 40px;
  border-bottom: 1px solid var(--yx-line-soft);
}

.page-about .about-jump__eyebrow {
  color: var(--yx-lake);
  margin-bottom: 14px;
}

.page-about .about-jump__nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .about-jump__nav .yx-index__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  border: 1px solid var(--yx-line);
  border-radius: 999px;
  background: #fff;
  color: var(--yx-ink);
  font-size: 14px;
  text-decoration: none;
  transition: border-color 0.2s ease, color 0.2s ease, background 0.2s ease;
}

.page-about .about-jump__nav .yx-index__item:hover,
.page-about .about-jump__nav .yx-index__item:focus-visible {
  border-color: var(--yx-lake);
  color: var(--yx-lake);
}

.page-about .about-jump__nav .yx-index__num {
  color: var(--yx-lake);
  font-size: 12px;
  letter-spacing: 0.06em;
}

/* ---------- 主体分栏 ---------- */
.page-about .about-main {
  background: var(--yx-paper);
  padding-block: 8px 72px;
}

.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
}

/* ---------- 左侧轨道 ---------- */
.page-about .about-rail {
  position: sticky;
  top: 62px;
  z-index: 6;
  background: var(--yx-paper);
  padding-block: 12px;
  margin-inline: -20px;
  padding-inline: 20px;
  border-bottom: 1px solid var(--yx-line-soft);
}

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

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

.page-about .about-rail__list::-webkit-scrollbar {
  display: none;
}

.page-about .about-rail__item {
  flex: 0 0 auto;
}

.page-about .about-rail__node {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  border: 1px solid var(--yx-line);
  border-radius: 999px;
  background: #fff;
  font-size: 13px;
  color: var(--yx-ink);
  text-decoration: none;
  white-space: nowrap;
  transition: border-color 0.2s ease, background 0.2s ease, color 0.2s ease;
}

.page-about .about-rail__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--yx-lake-soft);
  flex: 0 0 auto;
}

.page-about .about-rail__time {
  color: var(--yx-ink-2);
  font-size: 11px;
}

.page-about .about-rail__node:hover,
.page-about .about-rail__node:focus-visible {
  border-color: var(--yx-lake);
  color: var(--yx-lake);
}

.page-about .about-rail__node.is-active {
  background: var(--yx-lake);
  border-color: var(--yx-lake);
  color: #fff;
}

.page-about .about-rail__node.is-active .about-rail__dot {
  background: var(--yx-lime);
}

.page-about .about-rail__node.is-active .about-rail__time {
  color: rgba(255, 255, 255, 0.78);
}

/* ---------- 右侧正文流 ---------- */
.page-about .about-stream {
  min-width: 0;
  max-width: var(--about-body-w);
}

.page-about .about-chapter {
  scroll-margin-top: 120px;
  padding-block: 40px 8px;
  border-top: 1px solid var(--yx-line-soft);
}

.page-about .about-chapter:first-child {
  border-top: 0;
  padding-top: 16px;
}

.page-about .about-chapter__title {
  margin-bottom: 18px;
}

.page-about .about-chapter .yx-prose {
  max-width: 40em;
}

.page-about .about-chapter .yx-prose + .yx-prose {
  margin-top: 16px;
}

/* 旁注引语 */
.page-about .about-callout {
  margin: 32px 0 8px;
  padding: 4px 0 4px 20px;
  border-left: 2px solid var(--yx-lake);
}

.page-about .about-callout blockquote {
  margin: 0;
  font-size: 22px;
  line-height: 1.5;
  font-style: italic;
  font-weight: 600;
  color: var(--yx-night);
  letter-spacing: -0.01em;
}

.page-about .about-callout figcaption {
  margin-top: 10px;
  font-size: 13px;
  color: var(--yx-ink-2);
}

/* ---------- 阶段列表 ---------- */
.page-about .about-era {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  gap: 4px;
}

.page-about .about-era__item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 14px;
  padding: 20px 0;
  border-top: 1px solid var(--yx-line-soft);
}

.page-about .about-era__item:first-child {
  border-top: 1px solid var(--yx-line);
}

.page-about .about-era__num {
  font-size: 30px;
  line-height: 1;
  font-weight: 700;
  color: transparent;
  -webkit-text-stroke: 1px var(--yx-lake-soft);
  padding-top: 4px;
}

.page-about .about-era__body h3 {
  margin: 0 0 8px;
  font-size: 19px;
}

.page-about .about-era__body p {
  margin: 0;
  font-size: 16px;
  line-height: 1.75;
  color: var(--yx-ink);
}

/* ---------- 中段停顿图 ---------- */
.page-about .about-pause {
  margin: 36px 0 0;
  border-radius: var(--yx-radius-lg);
  overflow: hidden;
}

/* ---------- 团队分工 ---------- */
.page-about .about-team {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-team__cell {
  display: block;
  padding: 18px 18px 16px;
  background: var(--yx-mist);
  border-radius: var(--yx-radius);
  box-shadow: var(--yx-shadow);
  border: 1px solid transparent;
  transition: border-color 0.22s ease, background 0.22s ease;
}

.page-about .about-team__cell:hover,
.page-about .about-team__cell:focus-within,
.page-about .about-team__cell:focus-visible {
  border-color: var(--yx-lake);
  background: #fff;
  outline: none;
}

.page-about .about-team__num {
  display: block;
  font-size: 44px;
  line-height: 1;
  font-weight: 700;
  color: var(--yx-lake);
}

.page-about .about-team__role {
  display: block;
  margin-top: 10px;
  font-size: 16px;
  font-weight: 700;
  color: var(--yx-night);
}

.page-about .about-team__note {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--yx-ink-2);
}

/* ---------- 数据来源 ---------- */
.page-about .about-source {
  display: grid;
  gap: 22px;
}

.page-about .about-source__figure {
  margin: 0;
  border-radius: var(--yx-radius);
  overflow: hidden;
}

/* ---------- 长期做法 ---------- */
.page-about .about-keep {
  margin-top: 22px;
  gap: 18px;
}

.page-about .about-keep__item {
  padding: 20px 18px;
  background: #fff;
  border: 1px solid var(--yx-line-soft);
  border-radius: var(--yx-radius);
  border-left: 3px solid var(--yx-orange);
}

.page-about .about-keep__item h3 {
  margin: 0 0 10px;
  font-size: 18px;
}

.page-about .about-keep__item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--yx-ink);
}

/* ---------- 末尾动作 ---------- */
.page-about .about-cta {
  margin-top: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 链接风格（页面内正文链接） ---------- */
.page-about .about-stream a:not(.yx-btn):not(.about-rail__node):not(.yx-index__item) {
  color: var(--yx-lake);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

.page-about .about-stream a:not(.yx-btn):not(.about-rail__node):not(.yx-index__item):hover {
  color: var(--yx-orange);
}

/* ---------- 平板 ---------- */
@media (min-width: 768px) {
  .page-about .about-hero {
    padding-block: 72px 56px;
  }

  .page-about .about-numbers {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 24px;
  }

  .page-about .about-numbers__val {
    font-size: 40px;
  }

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

  .page-about .about-source {
    grid-template-columns: minmax(0, 1fr) 240px;
    align-items: start;
  }
}

/* ---------- 窄屏：团队说明常显 ---------- */
@media (max-width: 767px) {
  .page-about .about-hero__title {
    max-width: 100%;
  }

  .page-about .about-era__num {
    font-size: 24px;
  }

  .page-about .about-callout blockquote {
    font-size: 19px;
  }

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

/* ---------- 桌面：左侧固定时间轴 ---------- */
@media (min-width: 1024px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-shell-w) minmax(0, 1fr);
    gap: var(--about-shell-gap);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: 104px;
    margin-inline: 0;
    padding-inline: 0;
    padding-block: 0;
    border-bottom: 0;
    background: transparent;
  }

  .page-about .about-rail__lead {
    display: block;
    color: var(--yx-lake);
    margin-bottom: 16px;
    letter-spacing: 0.14em;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding-left: 22px;
    position: relative;
  }

  .page-about .about-rail__list::before {
    content: "";
    position: absolute;
    left: 5px;
    top: 12px;
    bottom: 12px;
    width: 1px;
    background: var(--yx-line);
  }

  .page-about .about-rail__item {
    position: relative;
  }

  .page-about .about-rail__node {
    display: grid;
    grid-template-columns: 8px minmax(0, 1fr) auto;
    align-items: center;
    gap: 10px;
    padding: 10px 0;
    background: transparent;
    border: 0;
    border-radius: 0;
    color: var(--yx-ink);
    font-size: 14px;
    transition: color 0.22s ease;
  }

  .page-about .about-rail__node::before {
    content: "";
    position: absolute;
    left: -22px;
    top: 50%;
    width: 12px;
    height: 12px;
    margin-top: -6px;
    border-radius: 50%;
    background: var(--yx-paper);
    border: 1px solid var(--yx-line);
    transition: background 0.22s ease, border-color 0.22s ease, transform 0.22s ease;
  }

  .page-about .about-rail__dot {
    width: 6px;
    height: 6px;
    background: var(--yx-lake-soft);
    transition: background 0.22s ease, transform 0.22s ease;
  }

  .page-about .about-rail__label {
    min-width: 0;
    letter-spacing: 0.01em;
  }

  .page-about .about-rail__time {
    font-size: 11px;
    color: var(--yx-ink-2);
  }

  .page-about .about-rail__node:hover,
  .page-about .about-rail__node:focus-visible {
    color: var(--yx-lake);
    border-color: transparent;
    background: transparent;
  }

  .page-about .about-rail__node.is-active {
    background: transparent;
    border-color: transparent;
    color: var(--yx-night);
    font-weight: 700;
  }

  .page-about .about-rail__node.is-active::before {
    background: var(--yx-lake);
    border-color: var(--yx-lake);
    transform: scale(1.18);
  }

  .page-about .about-rail__node.is-active .about-rail__dot {
    background: var(--yx-lime);
    transform: scale(1.4);
  }

  .page-about .about-rail__node.is-active .about-rail__time {
    color: var(--yx-lake);
  }

  .page-about .about-stream {
    max-width: 100%;
  }

  .page-about .about-chapter {
    padding-block: 56px 12px;
    scroll-margin-top: 96px;
  }

  .page-about .about-era {
    gap: 0;
  }

  .page-about .about-era__item {
    grid-template-columns: 80px minmax(0, 1fr);
    gap: 24px;
    padding: 26px 0;
  }

  .page-about .about-era__num {
    font-size: 44px;
  }

  .page-about .about-team {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0;
    border-top: 1px solid var(--yx-line);
    border-bottom: 1px solid var(--yx-line);
  }

  .page-about .about-team__cell {
    background: transparent;
    border: 0;
    border-left: 1px solid var(--yx-line-soft);
    border-radius: 0;
    box-shadow: none;
    padding: 24px 20px 20px;
    transition: background 0.24s ease;
  }

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

  .page-about .about-team__cell:hover,
  .page-about .about-team__cell:focus-within,
  .page-about .about-team__cell:focus-visible {
    background: var(--yx-lake-wash);
    border-color: var(--yx-line-soft);
  }

  .page-about .about-team__note {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    margin-top: 0;
    transition: max-height 0.28s ease, opacity 0.22s ease, margin-top 0.28s ease;
  }

  .page-about .about-team__cell:hover .about-team__note,
  .page-about .about-team__cell:focus-within .about-team__note,
  .page-about .about-team__cell:focus-visible .about-team__note {
    max-height: 180px;
    opacity: 1;
    margin-top: 10px;
  }

  .page-about .about-keep__item {
    padding: 26px 22px;
  }

  .page-about .about-pause {
    margin-top: 44px;
  }
}

/* ---------- 大屏 ---------- */
@media (min-width: 1440px) {
  .page-about .about-shell {
    --about-shell-w: 220px;
    --about-shell-gap: 88px;
  }

  .page-about .about-numbers__val {
    font-size: 46px;
  }
}

/* ---------- 减弱动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .about-jump__nav .yx-index__item,
  .page-about .about-rail__node,
  .page-about .about-rail__node::before,
  .page-about .about-rail__dot,
  .page-about .about-team__cell,
  .page-about .about-team__note {
    transition: none !important;
  }
}
<<<END>>>