.page-about {
  --about-gap: 18px;
  --about-rule: 64px;
  background: var(--ink-950);
  color: var(--text-hi);
}

.page-about .crumbs {
  padding: 20px 0 2px;
  font-family: var(--font-head);
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-mid);
}

.page-about .crumbs a {
  color: var(--text-mid);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur-fast) var(--ease), border-color var(--dur-fast) var(--ease);
}

.page-about .crumbs a:hover,
.page-about .crumbs a:focus-visible {
  color: var(--cyan-400);
  border-bottom-color: var(--cyan-700);
}

.page-about .crumbs span[aria-hidden="true"] {
  margin: 0 8px;
  color: var(--line-600);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding: 14px 0 44px;
}

.page-about .about-hero__frame {
  padding: 24px 20px 28px;
}

.page-about .about-hero .eyebrow {
  font-family: var(--font-head);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .22em;
  color: var(--cyan-400);
  margin: 0;
}

.page-about h1 {
  margin: 16px 0 18px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(28px, 6.2vw, 46px);
  line-height: 1.22;
  letter-spacing: -0.01em;
  color: var(--text-hi);
}

.page-about .lead {
  margin: 0;
  max-width: 62ch;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.8;
  color: var(--text-mid);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 16px;
  margin: 28px 0 0;
  padding: 22px 0 0;
  border-top: 1px solid var(--line-600);
}

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

.page-about .about-facts dt {
  font-family: var(--font-head);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--text-mid);
}

.page-about .about-facts dd {
  margin: 8px 0 0;
  font-size: 26px;
  line-height: 1;
  font-weight: 700;
}

/* ---------- 章节骨架 ---------- */

.page-about .about-chap {
  position: relative;
  padding: 46px 0 42px;
}

.page-about .about-chap--alt {
  background: var(--ink-900);
  border-top: 1px solid var(--line-600);
  border-bottom: 1px solid var(--line-600);
}

.page-about .about-chap__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}

.page-about .about-chap__mark {
  display: flex;
  align-items: baseline;
  gap: 14px;
}

.page-about .about-chap__num {
  font-family: var(--font-num);
  font-weight: 700;
  font-size: clamp(40px, 9vw, 68px);
  line-height: 0.9;
  color: var(--ink-800);
  -webkit-text-stroke: 1px var(--cyan-700);
}

.page-about .about-chap__side {
  font-family: var(--font-head);
  font-size: 12px;
  letter-spacing: .3em;
  color: var(--text-mid);
}

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

.page-about .about-chap__rule {
  display: block;
  width: var(--about-rule);
  height: 1px;
  margin: 0 0 20px;
  background: var(--cyan-700);
  transform: rotate(-16deg);
  transform-origin: left center;
}

.page-about h2 {
  margin: 0 0 18px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(22px, 3.6vw, 32px);
  line-height: 1.32;
  color: var(--text-hi);
}

.page-about h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.45;
  color: var(--text-hi);
}

.page-about .prose p {
  margin: 0 0 16px;
  max-width: 68ch;
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.85;
  color: var(--text-mid);
}

.page-about .prose p:last-child {
  margin-bottom: 0;
}

/* ---------- 图片 ---------- */

.page-about .about-fig {
  margin: 30px 0 0;
}

.page-about .about-fig img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line-600);
}

.page-about .about-fig figcaption {
  margin-top: 12px;
  max-width: 58ch;
  font-family: var(--font-head);
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--text-mid);
}

/* ---------- 版本时间线 ---------- */

.page-about .about-tl {
  list-style: none;
  margin: 6px 0 0;
  padding: 0 0 0 26px;
  position: relative;
}

.page-about .about-tl::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 10px;
  bottom: 12px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan-700), var(--line-600) 62%, transparent);
}

.page-about .about-tl__item {
  position: relative;
  padding: 0 0 32px;
  transition: transform var(--dur-base) var(--ease);
}

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

.page-about .about-tl__item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 6px;
  width: 11px;
  height: 11px;
  background: var(--ink-950);
  border: 1px solid var(--cyan-700);
  clip-path: polygon(0 0, 100% 0, 100% 68%, 68% 100%, 0 100%);
  transition: background var(--dur-fast) var(--ease), border-color var(--dur-fast) var(--ease);
}

.page-about .about-chap--alt .about-tl__item::before {
  background: var(--ink-900);
}

.page-about .about-tl__item:hover::before,
.page-about .about-tl__item:focus-within::before {
  background: var(--cyan-400);
  border-color: var(--cyan-400);
}

.page-about .about-tl__item:hover {
  transform: translateX(3px);
}

.page-about .about-tl__ver {
  margin: 0 0 4px;
  font-family: var(--font-num);
  font-weight: 700;
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--text-mid);
  transition: color var(--dur-fast) var(--ease);
}

.page-about .about-tl__item:hover .about-tl__ver {
  color: var(--cyan-400);
}

.page-about .about-tl__item p {
  margin: 0 0 10px;
  max-width: 64ch;
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.82;
  color: var(--text-mid);
}

.page-about .about-tl__item p:last-child {
  margin-bottom: 0;
}

/* ---------- 团队 ---------- */

.page-about .about-team {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
}

.page-about .about-team > li {
  min-width: 0;
  padding-top: 18px;
  border-top: 1px solid var(--line-600);
}

.page-about .about-team__n {
  font-family: var(--font-num);
  font-weight: 700;
  font-size: 30px;
  line-height: 1;
  margin: 0 0 10px;
}

.page-about .about-team h3 {
  margin-bottom: 8px;
}

.page-about .about-team p {
  margin: 0;
  font-family: var(--font-body);
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--text-mid);
}

/* ---------- 坚持与不做 ---------- */

.page-about .about-stand {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  margin-top: 6px;
}

.page-about .about-stand__col {
  min-width: 0;
  padding: 20px 18px 22px;
  background: var(--ink-800);
  border-left: 2px solid var(--cyan-700);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
}

.page-about .about-stand__col--skip {
  background: transparent;
  border-left-color: var(--amber-500);
  box-shadow: inset 0 0 0 1px var(--line-600);
}

.page-about .about-stand__col h3 {
  margin-bottom: 14px;
  font-size: 15px;
  letter-spacing: .14em;
  color: var(--cyan-400);
}

.page-about .about-stand__col--skip h3 {
  color: var(--amber-500);
}

.page-about .about-stand__col ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-stand__col li {
  position: relative;
  padding-left: 16px;
  margin-bottom: 14px;
  font-family: var(--font-body);
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--text-mid);
}

.page-about .about-stand__col li:last-child {
  margin-bottom: 0;
}

.page-about .about-stand__col li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 7px;
  height: 1px;
  background: var(--cyan-400);
}

.page-about .about-stand__col--skip li::before {
  background: var(--amber-500);
}

.page-about .about-stand__col strong {
  color: var(--text-hi);
  font-weight: 500;
}

.page-about .about-more {
  margin-top: 26px;
  padding-top: 16px;
  border-top: 1px solid var(--line-600);
}

.page-about .about-more summary {
  font-family: var(--font-head);
  font-size: 14px;
  font-weight: 500;
  color: var(--cyan-400);
  cursor: pointer;
}

.page-about .about-more summary:focus-visible {
  outline: 1px solid var(--cyan-700);
  outline-offset: 4px;
}

.page-about .about-more p {
  margin: 14px 0 0;
  max-width: 66ch;
  font-family: var(--font-body);
  font-size: 14.5px;
  line-height: 1.82;
  color: var(--text-mid);
}

/* ---------- 待办 ---------- */

.page-about .about-next {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
}

.page-about .about-next > li {
  min-width: 0;
  padding: 18px 0 0;
  border-top: 1px solid var(--line-600);
}

.page-about .about-next__tag {
  display: inline-block;
  margin-bottom: 10px;
  padding: 3px 9px;
  font-family: var(--font-num);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .1em;
  color: var(--violet-500);
  box-shadow: inset 0 0 0 1px var(--line-600);
}

.page-about .about-next p {
  margin: 0;
  font-family: var(--font-body);
  font-size: 14.5px;
  line-height: 1.82;
  color: var(--text-mid);
}

/* ---------- 页尾收束 ---------- */

.page-about .about-outro {
  padding: 52px 0 64px;
  background: var(--ink-950);
  border-top: 1px solid var(--line-600);
}

.page-about .about-fig--wide {
  margin: 0 0 34px;
}

.page-about .about-fig--wide img {
  border-left: none;
  border-right: none;
}

.page-about .about-outro__body {
  max-width: 72ch;
}

.page-about .about-outro .lead {
  color: var(--text-hi);
}

.page-about .about-links {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .about-links a {
  display: inline-block;
  padding: 9px 15px;
  font-family: var(--font-head);
  font-size: 14px;
  font-weight: 500;
  color: var(--text-hi);
  text-decoration: none;
  background: var(--ink-800);
  box-shadow: inset 0 0 0 1px var(--line-600);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 10px), calc(100% - 10px) 100%, 0 100%);
  transition: color var(--dur-fast) var(--ease), box-shadow var(--dur-fast) var(--ease);
}

.page-about .about-links a:hover,
.page-about .about-links a:focus-visible {
  color: var(--cyan-400);
  box-shadow: inset 0 0 0 1px var(--cyan-700);
}

/* ---------- 断点 ---------- */

@media (min-width: 480px) {
  .page-about .about-hero__frame {
    padding: 28px 26px 32px;
  }

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

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

@media (min-width: 768px) {
  .page-about .about-hero {
    padding: 20px 0 56px;
  }

  .page-about .about-hero__frame {
    padding: 36px 36px 40px;
  }

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

  .page-about .about-chap {
    padding: 62px 0 58px;
  }

  .page-about .about-team {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 22px;
  }

  .page-about .about-next {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 24px;
  }

  .page-about .about-outro {
    padding: 68px 0 80px;
  }
}

@media (min-width: 900px) {
  .page-about .about-chap__grid {
    grid-template-columns: 148px minmax(0, 1fr);
    gap: 0 40px;
  }

  .page-about .about-chap__mark {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
    position: sticky;
    top: calc(var(--topbar-h) + 42px);
    align-self: start;
  }

  .page-about .about-chap__side {
    writing-mode: vertical-rl;
    letter-spacing: .46em;
  }

  .page-about .about-fig--square {
    max-width: 420px;
  }

  .page-about .about-fig--team {
    max-width: 760px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-chap {
    padding: 84px 0 76px;
  }

  .page-about .about-chap__grid {
    grid-template-columns: 176px minmax(0, 1fr);
    gap: 0 56px;
  }

  .page-about .about-hero__frame {
    padding: 44px 48px 48px;
  }

  .page-about .about-stand {
    gap: 34px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-tl__item,
  .page-about .about-tl__item::before,
  .page-about .about-tl__ver,
  .page-about .crumbs a,
  .page-about .about-links a {
    transition-duration: 120ms;
  }

  .page-about .about-tl__item:hover {
    transform: none;
  }
}