.page-about {
  --ab-line-soft: rgba(44, 58, 64, .18);
  background: var(--paper);
  color: var(--char);
  overflow-x: hidden;
}

.page-about__crumb {
  padding-top: 24px;
  padding-bottom: 4px;
}

.page-about .ab-visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- 首屏 ---------- */

.page-about .ab-hero {
  padding: 24px 0 56px;
  border-bottom: 1px solid var(--line);
}

.page-about .ab-hero__inner {
  display: grid;
  gap: 32px;
}

.page-about .ab-hero__copy h1 {
  font-family: var(--f-display);
  font-weight: 900;
  font-size: clamp(30px, 5.2vw, 52px);
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--char);
  margin: 14px 0 0;
  max-width: 17ch;
}

.page-about .ab-hero__lede {
  font-size: 16px;
  line-height: 1.8;
  color: var(--char-soft);
  margin: 20px 0 0;
  max-width: 60ch;
}

.page-about .ab-hero__board {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  margin: 0;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-hero__cell {
  background: var(--paper);
  padding: 14px 16px 18px;
}

.page-about .ab-hero__cell dt {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--grey);
  margin: 0;
}

.page-about .ab-hero__val {
  font-family: var(--f-display);
  font-weight: 900;
  font-size: 30px;
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--char);
  font-variant-numeric: tabular-nums;
  margin: 8px 0 0;
}

.page-about .ab-hero__val span {
  font-family: var(--f-body);
  font-weight: 500;
  font-size: 13px;
  color: var(--char-soft);
  margin-left: 3px;
}

/* ---------- 章节编号与标题 ---------- */

.page-about .ab-chapter {
  font-family: var(--f-display);
  font-weight: 900;
  font-size: 44px;
  line-height: .88;
  letter-spacing: -0.04em;
  color: var(--red);
  font-variant-numeric: tabular-nums;
  margin: 0 0 14px;
}

.page-about .ab-chapter--light {
  color: var(--yellow);
}

.page-about .section {
  padding: 56px 0;
}

.page-about .section__title {
  font-family: var(--f-serif);
  font-weight: 600;
  font-size: clamp(23px, 3.4vw, 34px);
  line-height: 1.34;
  letter-spacing: -0.01em;
  color: var(--char);
  margin: 0 0 14px;
  max-width: 20ch;
}

.page-about .section__lede {
  font-size: 16px;
  line-height: 1.75;
  color: var(--char-soft);
  margin: 0;
  max-width: 56ch;
}

.page-about .section__head {
  margin-bottom: 32px;
}

/* ---------- 通用图文容器 ---------- */

.page-about .media {
  margin: 0;
  position: relative;
}

.page-about .media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  background: linear-gradient(135deg, var(--ink) 0%, var(--red-deep) 100%);
}

.page-about .media__caption {
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: .04em;
  line-height: 1.65;
  color: var(--grey);
  margin-top: 10px;
}

/* ---------- 01 起点 ---------- */

.page-about .ab-origin__grid {
  display: grid;
  gap: 32px;
}

.page-about .ab-origin__copy p {
  font-size: 16px;
  line-height: 1.82;
  color: var(--char-soft);
  margin: 0 0 16px;
  max-width: 60ch;
}

.page-about .ab-origin__figure {
  border-left: 1px solid var(--line-soft);
  padding-left: 16px;
}

/* ---------- 引文跨页 ---------- */

.page-about .ab-pull {
  background: var(--paper-2);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 40px 0;
}

.page-about .ab-pull__text {
  font-family: var(--f-serif);
  font-size: clamp(21px, 3.6vw, 34px);
  line-height: 1.5;
  letter-spacing: -0.01em;
  color: var(--char);
  margin: 0;
  max-width: 26ch;
  padding-left: 18px;
  border-left: 3px solid var(--red);
}

.page-about .ab-pull__by {
  color: var(--grey);
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: .06em;
  margin: 16px 0 0 21px;
}

/* ---------- 02 三块招牌 ---------- */

.page-about .ab-signs {
  background: var(--ink);
  color: var(--paper);
}

.page-about .ab-signs .section__title {
  color: var(--paper);
}

.page-about .ab-signs .section__lede {
  color: var(--paper-72);
}

.page-about .ab-signs__grid {
  display: grid;
  gap: 1px;
  background: var(--line-dark);
  border: 1px solid var(--steel);
}

.page-about .ab-sign {
  background: var(--ink);
  padding: 24px 20px 26px;
}

.page-about .ab-sign__no {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--yellow);
  margin: 0 0 12px;
}

.page-about .ab-sign__name {
  font-family: var(--f-display);
  font-weight: 900;
  font-size: 24px;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--paper);
  margin: 0 0 14px;
}

.page-about .ab-sign p.ab-sign__body {
  font-size: 15px;
  line-height: 1.78;
  color: var(--paper-72);
  margin: 0 0 16px;
}

.page-about .ab-sign p.ab-sign__for {
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: .03em;
  line-height: 1.6;
  color: var(--grey);
  margin: 0;
  padding-top: 14px;
  border-top: 1px solid var(--steel);
}

/* ---------- 03 团队 ---------- */

.page-about .ab-team__wide {
  margin: 0 0 40px;
}

.page-about .ab-team__wide img {
  max-height: 520px;
}

.page-about .ab-team__table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
}

.page-about .ab-team__table th,
.page-about .ab-team__table td {
  text-align: left;
  vertical-align: top;
  padding: 14px 16px 14px 0;
  border-bottom: 1px solid var(--line);
  line-height: 1.7;
}

.page-about .ab-team__table th {
  font-family: var(--f-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .1em;
  color: var(--grey);
  border-bottom: 1px solid var(--line-dark);
  padding-bottom: 10px;
}

.page-about .ab-team__table td:first-child {
  font-family: var(--f-serif);
  font-weight: 600;
  font-size: 17px;
  color: var(--char);
  white-space: nowrap;
}

.page-about .ab-team__table td:nth-child(2) {
  font-family: var(--f-mono);
  font-weight: 700;
  font-size: 20px;
  color: var(--red);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
  width: 72px;
}

.page-about .ab-team__table td:last-child {
  color: var(--char-soft);
}

/* ---------- 04 数据来源 ---------- */

.page-about .ab-source__grid {
  display: grid;
  gap: 32px;
}

.page-about .ab-source__copy p {
  font-size: 16px;
  line-height: 1.82;
  color: var(--char-soft);
  margin: 0 0 16px;
  max-width: 60ch;
}

.page-about .ab-steps {
  list-style: none;
  padding: 0;
  margin: 26px 0 0;
  border-top: 1px solid var(--line-dark);
}

.page-about .ab-steps__item {
  padding: 12px 0;
  border-bottom: 1px solid var(--line-soft);
  font-size: 15px;
  line-height: 1.6;
  color: var(--char);
}

.page-about .ab-steps__item .mono {
  display: inline-block;
  min-width: 68px;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--red);
}

.page-about .ab-source__figure {
  border-top: 3px solid var(--ink);
  padding-top: 12px;
}

/* ---------- 05 时间线 ---------- */

.page-about .ab-tl {
  list-style: none;
  padding: 0;
  margin: 32px 0 0;
}

.page-about .ab-tl__item {
  position: relative;
  margin-left: 4px;
  padding-left: 30px;
  border-left: 1px solid var(--line-dark);
}

.page-about .ab-tl__item:last-child {
  border-left-color: transparent;
}

.page-about .ab-tl__item::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 24px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--red);
}

.page-about .ab-tl__item:nth-child(even)::before {
  background: var(--yellow);
}

.page-about .ab-tl__node {
  border-bottom: 1px solid var(--line-soft);
}

.page-about .ab-tl__sum {
  list-style: none;
  cursor: pointer;
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
  align-items: baseline;
  padding: 14px 24px 14px 0;
  position: relative;
}

.page-about .ab-tl__sum::-webkit-details-marker {
  display: none;
}

.page-about .ab-tl__sum::after {
  content: "+";
  position: absolute;
  right: 0;
  top: 16px;
  font-family: var(--f-mono);
  font-size: 16px;
  line-height: 1;
  color: var(--grey);
}

.page-about .ab-tl__node[open] .ab-tl__sum::after {
  content: "–";
  color: var(--red);
}

.page-about .ab-tl__sum:focus-visible {
  outline: 2px solid var(--yellow);
  outline-offset: 3px;
}

.page-about .ab-tl__year {
  font-family: var(--f-display);
  font-weight: 900;
  font-size: 26px;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--char);
  font-variant-numeric: tabular-nums;
  flex: none;
}

.page-about .ab-tl__node[open] .ab-tl__year {
  color: var(--red);
}

.page-about .ab-tl__name {
  font-size: 15px;
  line-height: 1.55;
  color: var(--char-soft);
}

.page-about .ab-tl__body {
  margin: 0 0 18px;
  padding-right: 20px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--char-soft);
  max-width: 62ch;
}

/* ---------- 06 合作伙伴 ---------- */

.page-about .ab-partners__grid {
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-partner {
  background: var(--paper);
  padding: 26px 22px;
}

.page-about .ab-partner h3 {
  font-family: var(--f-display);
  font-weight: 900;
  font-size: 22px;
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: var(--char);
  margin: 0 0 12px;
}

.page-about .ab-partner p {
  font-size: 15px;
  line-height: 1.8;
  color: var(--char-soft);
  margin: 0 0 16px;
}

.page-about .ab-partner p.ab-partner__meta {
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--red);
  margin: 0;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

/* ---------- 07 收束 ---------- */

.page-about .ab-end {
  background: var(--ink);
  color: var(--paper);
}

.page-about .ab-end__title {
  font-family: var(--f-serif);
  font-weight: 600;
  font-size: clamp(25px, 4vw, 40px);
  line-height: 1.32;
  letter-spacing: -0.01em;
  color: var(--paper);
  margin: 0 0 20px;
  max-width: 20ch;
}

.page-about .ab-end__lede {
  font-size: 16px;
  line-height: 1.85;
  color: var(--paper-72);
  margin: 0 0 32px;
  max-width: 62ch;
}

.page-about .ab-end__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .ab-end__actions .btn {
  text-decoration: none;
}

/* ---------- 结尾指路 ---------- */

.page-about .ab-more {
  padding: 44px 0 72px;
}

.page-about .ab-more__note {
  font-size: 15px;
  line-height: 1.8;
  color: var(--char-soft);
  margin: 0;
  padding-top: 22px;
  border-top: 1px solid var(--line);
  max-width: 68ch;
}

.page-about .ab-more__note a {
  color: var(--red);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .ab-more__note a:focus-visible {
  outline: 2px solid var(--yellow);
  outline-offset: 3px;
}

/* ---------- 窄屏 ---------- */

@media (max-width: 719px) {
  .page-about .ab-chapter {
    font-size: 34px;
  }

  .page-about .ab-hero__val {
    font-size: 25px;
  }

  .page-about .ab-team__table thead {
    display: none;
  }

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

  .page-about .ab-team__table tr {
    border: 1px solid var(--line);
    background: var(--paper-2);
    padding: 14px 16px 16px;
    margin-bottom: 12px;
  }

  .page-about .ab-team__table td,
  .page-about .ab-team__table td:first-child,
  .page-about .ab-team__table td:nth-child(2) {
    border-bottom: 0;
    padding: 4px 0;
    width: auto;
    white-space: normal;
  }

  .page-about .ab-team__table td[data-label]::before {
    content: attr(data-label);
    display: block;
    font-family: var(--f-mono);
    font-size: 10px;
    letter-spacing: .12em;
    color: var(--grey);
    margin-bottom: 2px;
  }

  .page-about .ab-origin__figure,
  .page-about .ab-source__figure {
    border-left: 0;
    border-top: 1px solid var(--line-soft);
    padding-left: 0;
    padding-top: 12px;
  }

  .page-about .ab-source__figure {
    border-top: 3px solid var(--ink);
  }

  .page-about .ab-team__wide img {
    max-height: 320px;
  }

  .page-about .ab-end__actions .btn {
    flex: 1 1 100%;
    justify-content: center;
  }
}

/* ---------- 桌面 ---------- */

@media (min-width: 900px) {
  .page-about .ab-hero {
    padding: 40px 0 72px;
  }

  .page-about .ab-hero__inner {
    grid-template-columns: minmax(0, 1.12fr) minmax(300px, .88fr);
    gap: 64px;
    align-items: end;
  }

  .page-about .ab-hero__cell {
    padding: 18px 20px 22px;
  }

  .page-about .ab-hero__val {
    font-size: 34px;
  }

  .page-about .section {
    padding: 88px 0;
  }

  .page-about .section__head {
    margin-bottom: 44px;
  }

  .page-about .ab-origin__grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(340px, .95fr);
    gap: 64px;
    align-items: start;
  }

  .page-about .ab-origin__figure {
    padding-left: 24px;
    margin-top: 8px;
  }

  .page-about .ab-pull {
    padding: 56px 0;
  }

  .page-about .ab-signs__grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    margin-top: 8px;
  }

  .page-about .ab-sign {
    padding: 32px 28px 34px;
  }

  .page-about .ab-team__wide {
    margin-bottom: 56px;
  }

  .page-about .ab-source__grid {
    grid-template-columns: minmax(0, 1.08fr) minmax(340px, .92fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .ab-tl {
    margin-top: 40px;
  }

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

  .page-about .ab-partner {
    padding: 32px 30px 36px;
  }

  .page-about .ab-more {
    padding: 56px 0 96px;
  }
}

@media (min-width: 1140px) {
  .page-about .ab-hero__inner {
    gap: 80px;
  }

  .page-about .ab-origin__grid {
    gap: 80px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    animation-duration: .001ms !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
}

.page-about {
  --line-soft: currentColor;
}