.page-about {
  --about-rail-w: 216px;
  --about-gap: 72px;
  display: block;
}

/* ---------- 封面 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  background: var(--c-plateau);
  color: var(--c-snow);
  padding: 36px 0 52px;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(246, 249, 250, 0.055) 1px, transparent 1px),
    linear-gradient(90deg, rgba(246, 249, 250, 0.055) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
}

.page-about .about-hero > .shell {
  position: relative;
  z-index: 1;
}

.page-about .about-hero .crumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0 0 28px;
  padding: 0;
  list-style: none;
  font-size: 13px;
  color: var(--on-dark);
}

.page-about .about-hero .crumbs li + li::before {
  content: "/";
  margin-right: 6px;
  color: var(--line-dark);
}

.page-about .about-hero .crumbs a {
  color: var(--c-gold);
  text-decoration: none;
  border-bottom: 1px solid rgba(224, 160, 44, 0.45);
  padding-bottom: 2px;
}

.page-about .about-hero .crumbs a:hover,
.page-about .about-hero .crumbs a:focus-visible {
  border-bottom-color: var(--c-gold);
}

.page-about .about-hero .kicker {
  margin: 0 0 18px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--c-gold);
}

.page-about .about-hero__title {
  margin: 0 0 22px;
  max-width: 20ch;
  font-family: var(--font-display);
  font-size: clamp(30px, 6.4vw, 62px);
  font-weight: 700;
  line-height: 1.14;
  letter-spacing: -0.015em;
  color: var(--c-snow);
}

.page-about .about-hero__lead {
  margin: 0 0 38px;
  max-width: 46ch;
  font-size: 16px;
  line-height: 1.85;
  color: rgba(246, 249, 250, 0.82);
}

.page-about .about-hero__figures {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 22px 16px;
  margin: 0;
  padding: 26px 0 0;
  list-style: none;
  border-top: 1px solid var(--line-dark);
}

.page-about .about-hero__fig {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(22px, 4.6vw, 34px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: 0.02em;
  color: var(--c-snow);
}

.page-about .about-hero__cap {
  display: block;
  margin-top: 8px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--on-dark);
}

/* ---------- 主栅格 ---------- */
.page-about .about-main {
  padding: 40px 0 0;
}

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

/* ---------- 左侧章节索引 ---------- */
.page-about .about-rail {
  position: sticky;
  top: var(--header-h);
  z-index: 3;
  margin-bottom: 4px;
  padding-bottom: 2px;
  background: var(--c-snow);
  border-bottom: 1px solid var(--c-rule);
}

.page-about .about-rail__label {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--c-slate);
}

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

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

.page-about .about-rail__list li {
  flex: 0 0 auto;
}

.page-about .about-rail__list a {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  margin-right: 20px;
  padding-bottom: 9px;
  border-bottom: 2px solid transparent;
  color: var(--c-slate);
  font-size: 14px;
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.24s var(--ease), border-color 0.24s var(--ease);
}

.page-about .about-rail__list a:hover,
.page-about .about-rail__list a:focus-visible {
  color: var(--c-plateau);
  border-bottom-color: var(--c-gold);
}

.page-about .about-rail__year {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--c-lake);
}

/* ---------- 章节 ---------- */
.page-about .about-flow {
  min-width: 0;
  padding-bottom: 24px;
}

.page-about .about-chapter {
  padding: 40px 0 22px;
  border-top: 1px solid var(--c-rule);
  scroll-margin-top: calc(var(--header-h) + 72px);
}

.page-about .about-chapter:first-of-type {
  border-top: 0;
  padding-top: 24px;
}

.page-about .about-chapter__no {
  display: block;
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: clamp(24px, 3.6vw, 34px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--c-lake);
}

.page-about .about-chapter__title {
  margin: 0 0 20px;
  max-width: 24ch;
  font-family: var(--font-display);
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 700;
  line-height: 1.32;
  letter-spacing: -0.01em;
  color: var(--c-ink);
}

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

.page-about .about-chapter__tail {
  margin-top: 28px;
}

.page-about .prose a {
  color: var(--c-lake);
  text-decoration: none;
  border-bottom: 1px solid rgba(30, 127, 166, 0.5);
}

.page-about .prose a:hover,
.page-about .prose a:focus-visible {
  color: var(--c-plateau);
  border-bottom-color: var(--c-gold);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 32px 0 0;
}

.page-about .about-figure .figure-frame {
  background: var(--c-mist);
  overflow: hidden;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: 100%;
  max-width: 100%;
  object-fit: cover;
}

.page-about .figure-caption {
  margin: 12px 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--c-slate);
}

/* ---------- 团队分工表 ---------- */
.page-about .about-team {
  width: 100%;
  margin: 30px 0 0;
  border-collapse: collapse;
  font-size: 15px;
}

.page-about .about-team thead th {
  padding: 0 14px 12px 0;
  border-bottom: 1px solid var(--c-ink);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-align: left;
  color: var(--c-slate);
}

.page-about .about-team th,
.page-about .about-team td {
  padding: 20px 14px 20px 0;
  border-top: 1px solid var(--c-rule);
  text-align: left;
  vertical-align: top;
}

.page-about .about-team tbody tr {
  transition: background-color 0.22s var(--ease);
}

.page-about .about-team tbody tr:hover,
.page-about .about-team tbody tr:focus-within {
  background-color: rgba(211, 230, 238, 0.38);
}

.page-about .about-team__name {
  display: block;
  font-size: 16px;
  font-weight: 700;
  color: var(--c-ink);
  line-height: 1.5;
}

.page-about .about-team__detail {
  display: block;
  margin-top: 8px;
  max-width: 40em;
  font-size: 13px;
  font-weight: 400;
  line-height: 1.7;
  color: var(--c-slate);
}

.page-about .about-team__num {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 700;
  color: var(--c-plateau);
  white-space: nowrap;
}

/* ---------- 覆盖与语言：非对称双栏 ---------- */
.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
  margin-top: 4px;
}

.page-about .about-split__media {
  margin-top: 0;
}

/* ---------- 版本演进 ---------- */
.page-about .about-versions {
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-versions__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 22px 0;
  border-top: 1px solid var(--c-rule);
}

.page-about .about-versions__item:last-child {
  border-bottom: 1px solid var(--c-rule);
}

.page-about .about-versions__ver {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--c-lake);
}

.page-about .about-versions__title {
  margin: 0;
  font-size: 18px;
  font-weight: 700;
  line-height: 1.5;
  color: var(--c-ink);
}

.page-about .about-versions__text {
  margin: 0;
  max-width: 42em;
  font-size: 15px;
  line-height: 1.78;
  color: var(--ink-soft);
}

.page-about .about-versions__text a {
  color: var(--c-lake);
  text-decoration: none;
  border-bottom: 1px solid rgba(30, 127, 166, 0.5);
}

.page-about .about-versions__text a:hover,
.page-about .about-versions__text a:focus-visible {
  color: var(--c-plateau);
  border-bottom-color: var(--c-gold);
}

.page-about .about-versions__item--now {
  padding-left: 18px;
  border-left: 3px solid var(--c-gold);
  background: linear-gradient(90deg, rgba(247, 228, 190, 0.6), rgba(247, 228, 190, 0));
}

/* ---------- 收束 ---------- */
.page-about .about-chapter--close {
  padding-bottom: 56px;
}

.page-about .about-close {
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-close li {
  position: relative;
  padding: 20px 0 20px 26px;
  border-top: 1px solid var(--c-rule);
  font-size: 17px;
  line-height: 1.7;
  color: var(--c-ink);
  max-width: 38em;
}

.page-about .about-close li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 30px;
  width: 10px;
  height: 10px;
  background: var(--c-gold);
}

.page-about .about-close__links {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 26px;
  margin: 34px 0 0;
}

.page-about .about-close__links a {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--c-plateau);
  text-decoration: none;
  padding-bottom: 3px;
  border-bottom: 1px solid var(--c-lake);
  transition: color 0.22s var(--ease), border-color 0.22s var(--ease);
}

.page-about .about-close__links a:hover,
.page-about .about-close__links a:focus-visible {
  color: var(--c-ink);
  border-bottom-color: var(--c-gold);
}

/* ---------- 窄屏表格折叠 ---------- */
@media (max-width: 699px) {
  .page-about .about-team thead {
    display: none;
  }

  .page-about .about-team,
  .page-about .about-team tbody,
  .page-about .about-team tr,
  .page-about .about-team th,
  .page-about .about-team td {
    display: block;
    width: 100%;
  }

  .page-about .about-team tr {
    padding: 20px 0;
    border-top: 1px solid var(--c-rule);
  }

  .page-about .about-team th,
  .page-about .about-team td {
    padding: 0;
    border-top: 0;
  }

  .page-about .about-team__num {
    margin: 10px 0 4px;
    font-size: 17px;
  }
}

/* ---------- 桌面端：3 : 7 不对称双栏 ---------- */
@media (min-width: 1000px) {
  .page-about .about-hero {
    padding: 48px 0 80px;
  }

  .page-about .about-main {
    padding-top: 64px;
  }

  .page-about .about-grid {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    column-gap: var(--about-gap);
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 32px);
    align-self: start;
    margin: 0;
    padding: 0;
    background: transparent;
    border-bottom: 0;
  }

  .page-about .about-rail__list {
    display: block;
    padding: 0;
    overflow: visible;
  }

  .page-about .about-rail__list li {
    display: block;
  }

  .page-about .about-rail__list a {
    display: flex;
    margin: 0;
    padding: 12px 0 12px 18px;
    border-bottom: 0;
    border-left: 2px solid var(--c-rule);
    white-space: normal;
    transition: color 0.24s var(--ease), border-color 0.24s var(--ease), padding-left 0.24s var(--ease);
  }

  .page-about .about-rail__list a:hover,
  .page-about .about-rail__list a:focus-visible {
    color: var(--c-ink);
    border-bottom-color: transparent;
    border-left-color: var(--c-gold);
    padding-left: 24px;
  }

  .page-about .about-chapter {
    padding: 72px 0 28px;
    scroll-margin-top: calc(var(--header-h) + 32px);
  }

  .page-about .about-chapter:first-of-type {
    padding-top: 4px;
  }

  .page-about .about-chapter--close {
    padding-bottom: 96px;
  }
}

/* ---------- 中屏：表格式版本条与左右分栏 ---------- */
@media (min-width: 700px) {
  .page-about .about-versions__item {
    grid-template-columns: 120px minmax(0, 1fr);
    column-gap: 32px;
    align-items: start;
  }

  .page-about .about-versions__ver {
    grid-column: 1;
    grid-row: 1 / span 2;
    padding-top: 5px;
  }

  .page-about .about-versions__title {
    grid-column: 2;
    grid-row: 1;
  }

  .page-about .about-versions__text {
    grid-column: 2;
    grid-row: 2;
  }
}

@media (min-width: 760px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 1.32fr) minmax(0, 1fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .about-figure--narrow {
    max-width: 420px;
  }
}
<<<END>>>