.page-about {
  --about-num-w: 56px;
  --about-sec-pad: 56px;
  --about-cream-line: rgba(11, 31, 26, 0.16);
  --about-cream-hover: rgba(11, 31, 26, 0.06);
}

.page-about .crumbs {
  padding-top: 24px;
}

.page-about .crumbs__current {
  color: var(--gray);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
}

/* ---------- 首屏 ---------- */

.page-about .about-head {
  padding: 32px 0 40px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 44px;
}

.page-about .about-head__title {
  margin: 14px 0 20px;
  font-size: clamp(30px, 7vw, 54px);
  line-height: 1.1;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--white);
  max-width: 20ch;
}

.page-about .about-head__lede {
  margin: 0 0 32px;
  max-width: 64ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--gray);
}

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

.page-about .about-head__stats .stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  background: var(--ink);
  padding: 18px 16px;
}

.page-about .about-head__stats .stat__value {
  font-size: 26px;
  line-height: 1;
  font-weight: 600;
  color: var(--yellow);
}

.page-about .about-head__stats .stat__label {
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: 0.04em;
  color: var(--gray);
}

/* ---------- 主体两栏 ---------- */

.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 36px;
  align-items: start;
}

.page-about .about-rail {
  border-top: 1px solid var(--line);
  padding-top: 16px;
}

.page-about .about-rail .toc__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-rail .toc__link {
  display: inline-block;
  font-size: 13px;
  line-height: 1.6;
  color: var(--gray);
  text-decoration: none;
  white-space: nowrap;
}

.page-about .about-rail .toc__link:hover,
.page-about .about-rail .toc__link[aria-current="true"] {
  color: var(--yellow);
}

.page-about .about-rail__top {
  display: inline-block;
  margin-top: 16px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--gray);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  padding-bottom: 2px;
}

.page-about .about-rail__top:hover {
  color: var(--yellow);
  border-bottom-color: var(--yellow);
}

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

/* ---------- 章节骨架 ---------- */

.page-about .about-sec {
  padding: 0 0 var(--about-sec-pad);
}

.page-about .about-sec__band {
  display: block;
  height: 8px;
  background: var(--yellow);
}

.page-about .about-sec__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  padding-top: 28px;
}

.page-about .about-sec__num {
  font-size: 34px;
  line-height: 1;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--yellow);
  opacity: 0.92;
}

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

.page-about .about-sec__title {
  margin: 0 0 16px;
  font-size: clamp(20px, 3.4vw, 27px);
  line-height: 1.32;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--white);
  max-width: 26ch;
}

.page-about .about-sec__lede {
  margin: 0 0 20px;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--gray);
}

.page-about .about-sec__text {
  margin: 0 0 16px;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--gray);
}

.page-about .about-sec__text--note {
  margin-top: 18px;
  font-size: 13px;
  color: var(--gray-dim);
}

.page-about .about-sec__figure {
  margin: 24px 0 0;
}

.page-about .about-sec__figure .media__caption,
.page-about .about-split__media .media__caption {
  margin-top: 10px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--gray-dim);
}

/* ---------- 01 分栏 ---------- */

.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
}

.page-about .about-split__media {
  margin: 0;
  min-width: 0;
}

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

/* ---------- 02 时间线 ---------- */

.page-about .about-timeline {
  position: relative;
  margin: 8px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 12px;
  bottom: 28px;
  width: 1px;
  background: var(--line);
}

.page-about .about-timeline__item {
  position: relative;
  padding: 0 0 34px 30px;
}

.page-about .about-timeline__item:last-child {
  padding-bottom: 0;
}

.page-about .about-timeline__dot {
  position: absolute;
  left: 0;
  top: 9px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--yellow);
}

.page-about .about-timeline__year {
  margin: 0 0 6px;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--yellow);
}

.page-about .about-timeline__title {
  margin: 0 0 8px;
  font-size: 16px;
  line-height: 1.5;
  font-weight: 700;
  color: var(--white);
}

.page-about .about-timeline__text {
  margin: 0 0 10px;
  max-width: 58ch;
  font-size: 14px;
  line-height: 1.8;
  color: var(--gray);
}

.page-about .about-timeline__link {
  display: inline-block;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  padding-bottom: 2px;
}

.page-about .about-timeline__link:hover {
  color: var(--yellow);
  border-bottom-color: var(--yellow);
}

/* ---------- 03 / 04 奶油阅读区 ---------- */

.page-about .about-cream {
  background: var(--cream);
  color: var(--ink);
  padding: 40px 22px 46px;
  margin-bottom: var(--about-sec-pad);
}

.page-about .about-cream .about-sec {
  padding-bottom: 0;
}

.page-about .about-cream .about-sec + .about-sec {
  margin-top: 42px;
  padding-top: 38px;
  border-top: 1px solid var(--about-cream-line);
}

.page-about .about-cream .about-sec__num {
  color: var(--ink);
  opacity: 0.55;
}

.page-about .about-cream .about-sec__title {
  color: var(--ink);
}

.page-about .about-cream .about-sec__lede,
.page-about .about-cream .about-sec__text {
  color: var(--ink);
  opacity: 0.78;
}

.page-about .about-cream .about-sec__figure {
  margin-top: 20px;
}

.page-about .about-cream .about-sec__figure .media__caption {
  color: var(--ink);
  opacity: 0.6;
}

/* 分工表 */

.page-about .about-roles {
  width: 100%;
  border-collapse: collapse;
  margin-top: 4px;
}

.page-about .about-roles__caption {
  text-align: left;
  padding-bottom: 12px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--ink);
  opacity: 0.55;
}

.page-about .about-roles th,
.page-about .about-roles td {
  text-align: left;
  vertical-align: top;
  padding: 14px 12px 14px 0;
  border-bottom: 1px solid var(--about-cream-line);
  font-size: 14px;
  line-height: 1.7;
  color: var(--ink);
}

.page-about .about-roles thead th {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink);
  opacity: 0.55;
  padding-bottom: 10px;
}

.page-about .about-roles__name {
  width: 96px;
  font-weight: 700;
  white-space: nowrap;
}

.page-about .about-roles tbody tr:hover {
  background: var(--about-cream-hover);
}

.page-about .about-roles tbody tr:hover .about-roles__name {
  box-shadow: inset 3px 0 0 var(--yellow);
}

/* 四步流程 */

.page-about .about-steps {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 8px 0 0;
  padding: 0;
  list-style: none;
  background: var(--about-cream-line);
  border: 1px solid var(--about-cream-line);
}

.page-about .about-steps__item {
  background: var(--cream);
  padding: 20px 18px;
}

.page-about .about-steps__idx {
  display: block;
  margin-bottom: 8px;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--ink);
  opacity: 0.5;
}

.page-about .about-steps__title {
  margin: 0 0 8px;
  font-size: 16px;
  line-height: 1.5;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-steps__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--ink);
  opacity: 0.78;
}

/* ---------- 05 节奏清单 ---------- */

.page-about .about-facts {
  margin: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-facts__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-facts__key {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--yellow);
}

.page-about .about-facts__val {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--gray);
  max-width: 62ch;
}

/* ---------- 06 三条通道 ---------- */

.page-about .about-paths {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  margin-top: 8px;
}

.page-about .about-paths__item {
  display: flex;
  flex-direction: column;
  gap: 10px;
  background: var(--ink);
  padding: 22px 18px 20px;
}

.page-about .about-paths__idx {
  margin: 0;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--cyan);
}

.page-about .about-paths__title {
  margin: 0;
  font-size: 17px;
  line-height: 1.45;
  font-weight: 700;
  color: var(--white);
}

.page-about .about-paths__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--gray);
}

.page-about .about-paths__link {
  align-self: flex-start;
  margin-top: 4px;
}

/* ---------- 07 备案 ---------- */

.page-about .about-legal {
  margin: 0 0 8px;
  border-top: 1px solid var(--line);
}

.page-about .about-legal__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-legal__key {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--gray-dim);
}

.page-about .about-legal__val {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--white);
  word-break: break-all;
}

.page-about .about-legal__val.is-key {
  color: var(--yellow);
}

.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

/* ---------- 返回顶部 ---------- */

.page-about .to-top {
  position: fixed;
  right: var(--pad-x);
  bottom: 20px;
  z-index: 60;
}

/* ---------- 断点 ---------- */

@media (min-width: 640px) {
  .page-about .about-head__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-head__stats .stat {
    padding: 22px 18px;
  }

  .page-about .about-head__stats .stat__value {
    font-size: 30px;
  }

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

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

  .page-about .about-legal__row {
    grid-template-columns: 110px minmax(0, 1fr);
    gap: 16px;
    align-items: baseline;
  }
}

@media (min-width: 860px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.82fr);
    gap: 32px;
  }

  .page-about .about-cream {
    padding: 48px 34px 54px;
  }

  .page-about .about-roles th,
  .page-about .about-roles td {
    padding: 16px 20px 16px 0;
  }

  .page-about .about-roles__name {
    width: 120px;
  }

  .page-about .about-facts__row {
    grid-template-columns: 120px minmax(0, 1fr);
    gap: 20px;
    align-items: baseline;
  }
}

@media (min-width: 960px) {
  .page-about {
    --about-num-w: 92px;
    --about-sec-pad: 72px;
  }

  .page-about .about-head {
    padding: 44px 0 52px;
    margin-bottom: 56px;
  }

  .page-about .about-head__lede {
    font-size: 17px;
  }

  .page-about .about-layout {
    grid-template-columns: var(--rail) minmax(0, 1fr);
    gap: 52px;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--bar-h-short) + 28px);
    border-top: 0;
    border-left: 1px solid var(--line);
    padding: 0 0 0 20px;
  }

  .page-about .about-rail .toc__list {
    display: block;
  }

  .page-about .about-rail .toc__list li + li {
    margin-top: 10px;
  }

  .page-about .about-rail .toc__link {
    white-space: normal;
  }

  .page-about .about-rail__top {
    margin-top: 22px;
  }

  .page-about .about-sec__grid {
    grid-template-columns: var(--about-num-w) minmax(0, 1fr);
    gap: 34px;
    padding-top: 32px;
  }

  .page-about .about-sec__num {
    font-size: 48px;
  }

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

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

@media (prefers-reduced-motion: reduce) {
  .page-about .about-sec__band {
    transition: none;
  }
}