.page-about {
  --about-rail-w: 232px;
  --about-gap: 64px;
  --about-stone-100: #EFEBE3;
  --about-stone-200: #E4DED2;
  --about-lake-hover: #D8E9EF;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: 44px 0 0;
  max-width: 46em;
}

.page-about .about-hero__title {
  font-family: var(--font-head);
  font-size: clamp(32px, 5.6vw, 58px);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: -.022em;
  color: var(--ink-900);
  margin: 16px 0 0;
}

.page-about .about-hero__lead {
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.85;
  color: var(--ink-70);
  max-width: 32em;
  margin: 22px 0 0;
}

/* ---------- 骨架：宽边栏 + 窄正文 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 40px;
  align-items: start;
  margin-top: 72px;
}

.page-about .about-rail {
  padding-top: 6px;
}

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

/* ---------- 侧栏时间线 ---------- */
.page-about .about-tl {
  list-style: none;
  margin: 16px 0 0;
  padding: 0 0 6px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: thin;
}

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

.page-about .about-tl__link {
  display: block;
  padding: 7px 14px;
  border: 1px solid var(--hair);
  border-radius: var(--r-pill);
  text-decoration: none;
  color: var(--ink-70);
  transition: border-color var(--t-fast) var(--ease), background var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}

.page-about .about-tl__link:hover,
.page-about .about-tl__link:focus-visible {
  border-color: var(--sun-500);
  background: var(--sun-100);
  color: var(--ink-900);
}

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

.page-about .about-tl__year {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--clay-400);
}

.page-about .about-tl__label {
  display: block;
  font-family: var(--font-ui);
  font-size: 12.5px;
  line-height: 1.4;
  margin-top: 2px;
  white-space: nowrap;
}

.page-about .about-rail__foot {
  margin: 20px 0 0;
  padding: 14px 0 0;
  border-top: 1px solid var(--hair);
  font-family: var(--font-ui);
  font-size: 12px;
  line-height: 1.7;
  color: var(--ink-50);
}

.page-about .about-rail__ver {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--lake-700);
}

/* ---------- 章节 ---------- */
.page-about .about-sec + .about-sec {
  margin-top: 84px;
}

.page-about .about-sec__title {
  font-family: var(--font-head);
  font-size: clamp(23px, 3.2vw, 33px);
  font-weight: 800;
  line-height: 1.26;
  letter-spacing: -.016em;
  color: var(--ink-900);
  margin: 14px 0 0;
  max-width: 22em;
}

.page-about .about-sec__title--sm {
  font-size: clamp(20px, 2.4vw, 25px);
}

.page-about .about-copy {
  margin-top: 20px;
  max-width: 34em;
}

.page-about .about-copy--tight {
  margin-top: 24px;
}

.page-about .about-copy p {
  font-family: var(--font-body);
  font-size: 16.5px;
  line-height: 1.85;
  color: var(--ink-70);
}

.page-about .about-copy p + p {
  margin-top: 1.1em;
}

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

.page-about .about-fig--narrow {
  max-width: 620px;
}

.page-about .about-fig .ly-figure__frame img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 四步流程 ---------- */
.page-about .about-steps {
  list-style: none;
  margin: 32px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
}

.page-about .about-step {
  padding-top: 18px;
  border-top: 2px solid var(--stone-300);
  transition: border-color var(--t-fast) var(--ease);
}

.page-about .about-step:focus-visible {
  outline: none;
  border-top-color: var(--sun-500);
  box-shadow: 0 0 0 2px var(--sun-500), 0 0 0 4px var(--paper-050);
}

.page-about .about-step__num {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--lake-700);
  padding: 2px 8px;
  border-radius: var(--r-s);
  background: transparent;
  transition: background var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}

.page-about .about-step:focus-visible .about-step__num,
.page-about .about-step:hover .about-step__num {
  background: var(--sun-100);
}

.page-about .about-step__name {
  display: block;
  font-family: var(--font-head);
  font-size: 17px;
  font-weight: 700;
  color: var(--ink-900);
  margin-top: 10px;
}

.page-about .about-step__desc {
  display: block;
  font-family: var(--font-body);
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--ink-70);
  margin-top: 8px;
}

/* ---------- 沿革时间线 ---------- */
.page-about .about-miles {
  list-style: none;
  margin: 32px 0 0;
  padding: 0;
  border-top: 1px solid var(--hair);
}

.page-about .about-mile {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr);
  gap: 18px;
  padding: 22px 0;
  border-bottom: 1px solid var(--hair);
}

.page-about .about-mile__year {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -.01em;
  color: var(--lake-700);
  align-self: start;
}

.page-about .about-mile--now .about-mile__year {
  color: var(--ink-900);
  background: var(--sun-100);
  padding: 2px 9px;
  border-radius: var(--r-s);
  justify-self: start;
  font-size: 18px;
}

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

.page-about .about-mile__title {
  font-family: var(--font-head);
  font-size: 17.5px;
  font-weight: 700;
  color: var(--ink-900);
  margin: 0 0 8px;
}

.page-about .about-mile__body p {
  font-family: var(--font-body);
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--ink-70);
  margin: 0;
  max-width: 32em;
}

/* ---------- 对照表 ---------- */
.page-about .about-map {
  margin-top: 30px;
  border: 1px solid var(--hair);
  border-radius: var(--r-m);
  overflow-x: auto;
  background: var(--paper-050);
  -webkit-overflow-scrolling: touch;
}

.page-about .about-map__cap {
  caption-side: top;
  text-align: left;
  padding: 14px 18px 0;
  font-family: var(--font-ui);
  font-size: 12.5px;
  color: var(--ink-50);
  letter-spacing: .02em;
}

.page-about .about-map table {
  width: 100%;
  min-width: 600px;
  border-collapse: collapse;
  font-family: var(--font-ui);
  font-size: 14px;
}

.page-about .about-map thead th {
  text-align: left;
  padding: 13px 16px;
  font-weight: 600;
  font-size: 12.5px;
  letter-spacing: .04em;
  color: var(--ink-70);
  border-bottom: 1px solid var(--hair);
  white-space: nowrap;
}

.page-about .about-map thead th:nth-child(1) {
  background: var(--about-stone-100);
}

.page-about .about-map thead th:nth-child(2) {
  background: var(--lake-050);
}

.page-about .about-map thead th:nth-child(3) {
  background: var(--sun-100);
}

.page-about .about-map td {
  padding: 13px 16px;
  border-bottom: 1px solid var(--hair);
  vertical-align: top;
  line-height: 1.55;
  color: var(--ink-900);
  transition: background var(--t-fast) var(--ease);
}

.page-about .about-map td:nth-child(1) {
  background: var(--about-stone-100);
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--ink-70);
}

.page-about .about-map td:nth-child(2) {
  background: var(--lake-050);
}

.page-about .about-map tbody tr:last-child td {
  border-bottom: 0;
}

.page-about .about-map tr.is-diff td:nth-child(1) {
  box-shadow: inset 3px 0 0 var(--brick-600);
}

.page-about .about-map tbody tr:hover td:nth-child(1) {
  background: var(--about-stone-200);
}

.page-about .about-map tbody tr:hover td:nth-child(2) {
  background: var(--about-lake-hover);
}

.page-about .about-map tbody tr:hover td:nth-child(3) {
  background: var(--sun-100);
}

/* ---------- 三条线 ---------- */
.page-about .about-lines {
  margin-top: 32px;
  border-top: 1px solid var(--hair);
}

.page-about .about-line {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 16px;
  padding: 22px 0;
  border-bottom: 1px solid var(--hair);
}

.page-about .about-line__num {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--clay-400);
  margin: 3px 0 0;
}

.page-about .about-line__title {
  font-family: var(--font-head);
  font-size: 19px;
  font-weight: 700;
  color: var(--ink-900);
  margin: 0 0 8px;
}

.page-about .about-line__text {
  font-family: var(--font-body);
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--ink-70);
  margin: 0;
  max-width: 33em;
}

/* ---------- 在办清单 ---------- */
.page-about .about-acc {
  margin-top: 28px;
}

.page-about .about-acc .ly-acc__inner p {
  font-family: var(--font-body);
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--ink-70);
  margin: 0;
  max-width: 32em;
}

.page-about .about-quote {
  margin: 36px 0 0;
  padding: 20px 0 20px 22px;
  border-left: 3px solid var(--clay-400);
  max-width: 36em;
}

.page-about .about-quote p {
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-70);
  margin: 0;
}

.page-about .about-quote__act {
  margin-top: 16px;
}

/* ---------- 收尾 ---------- */
.page-about .about-sec--tail {
  margin-top: 84px;
  padding-top: 34px;
  border-top: 1px solid var(--hair);
}

.page-about .about-acts {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

/* ---------- 平板及以上 ---------- */
@media (min-width: 780px) {
  .page-about .about-steps {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 24px 28px;
  }
}

@media (min-width: 960px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: var(--about-gap);
    margin-top: 88px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 112px;
    align-self: start;
  }

  .page-about .about-tl {
    display: block;
    overflow: visible;
    padding: 0;
    margin-top: 20px;
    border-left: 1px solid var(--hair);
  }

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

  .page-about .about-tl__link {
    border: 0;
    border-radius: 0;
    padding: 11px 0 11px 18px;
  }

  .page-about .about-tl__link::before {
    content: "";
    position: absolute;
    left: -1px;
    top: 50%;
    width: 2px;
    height: 100%;
    background: var(--sun-500);
    transform: translateY(-50%) scaleY(0);
    transform-origin: center;
    transition: transform var(--t-fast) var(--ease);
  }

  .page-about .about-tl__link:hover,
  .page-about .about-tl__link:focus-visible {
    background: transparent;
    border-color: transparent;
  }

  .page-about .about-tl__link:hover::before,
  .page-about .about-tl__link:focus-visible::before {
    transform: translateY(-50%) scaleY(1);
  }

  .page-about .about-tl__label {
    white-space: normal;
  }

  .page-about .about-steps {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 22px;
  }

  .page-about .about-mile {
    grid-template-columns: 96px minmax(0, 1fr);
    gap: 24px;
    padding: 24px 0;
  }

  .page-about .about-mile__year {
    font-size: 22px;
  }
}

@media (min-width: 1120px) {
  .page-about .about-hero {
    padding-top: 56px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-tl__link,
  .page-about .about-tl__link::before,
  .page-about .about-step,
  .page-about .about-step__num,
  .page-about .about-map td {
    transition: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-tl__link::before {
    transform: translateY(-50%) scaleY(1);
  }
}
</main>