.page-about {
  --about-edge: clamp(18px, 4.5vw, 56px);
  --about-gap: clamp(22px, 4vw, 44px);
  background: var(--paper);
  color: var(--char);
  font-family: var(--font-body);
  line-height: 1.75;
}

.page-about .about-wrap {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--about-edge);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  border-bottom: 1px solid var(--rule);
  padding-block: clamp(20px, 4vw, 40px) clamp(26px, 4vw, 48px);
  background:
    linear-gradient(180deg, rgba(38, 224, 214, 0.07), rgba(244, 238, 226, 0) 62%),
    var(--paper);
}

.page-about .about-crumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 clamp(18px, 3vw, 32px);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--muted);
}

.page-about .about-crumb .breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  margin-right: 8px;
  color: var(--rule);
}

.page-about .about-crumb .breadcrumb__link {
  color: var(--ink-2);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.18s var(--ease);
}

.page-about .about-crumb .breadcrumb__link:hover,
.page-about .about-crumb .breadcrumb__link:focus-visible {
  border-bottom-color: var(--coral);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(16px, 3vw, 28px);
}

.page-about .about-kicker {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--sand);
}

.page-about .about-hero h1 {
  margin: 0;
  max-width: 15em;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 5.6vw, 58px);
  line-height: 1.14;
  letter-spacing: 0.01em;
  color: var(--ink);
}

.page-about .about-lede {
  margin: clamp(16px, 2.4vw, 24px) 0 0;
  max-width: 40em;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.85;
  color: var(--char);
}

.page-about .about-hero__side {
  display: none;
  margin: 0;
}

.page-about .about-stats {
  list-style: none;
  margin: clamp(24px, 3.4vw, 42px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
}

.page-about .about-stats li {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 16px 16px;
  background: var(--paper);
}

.page-about .about-stats__num {
  font-family: var(--font-mono);
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}

.page-about .about-stats__unit {
  margin-left: 2px;
  font-size: 13px;
  font-weight: 500;
  color: var(--sand);
}

.page-about .about-stats__label {
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--muted);
}

/* ---------- 主体两栏 ---------- */
.page-about .about-body {
  max-width: var(--maxw);
  margin-inline: auto;
  padding: clamp(28px, 5vw, 64px) var(--about-edge) clamp(40px, 6vw, 80px);
  display: grid;
  gap: var(--about-gap);
}

.page-about .about-chapters {
  display: none;
}

.page-about .about-chapters__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px 0;
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.page-about .about-chapters__link:hover,
.page-about .about-chapters__link:focus-visible {
  color: var(--ink);
  border-bottom-color: var(--rule);
}

.page-about .about-chapters__link.is-current {
  color: var(--ink);
  border-bottom-color: var(--sand);
}

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

.page-about .about-chapters__link.is-current .about-chapters__num {
  color: var(--coral);
}

/* ---------- 章节 ---------- */
.page-about .about-block {
  position: relative;
  scroll-margin-top: calc(var(--bar-h) + 24px);
}

.page-about .about-block + .about-block {
  margin-top: clamp(34px, 5vw, 72px);
}

.page-about .about-block__head {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px;
  margin-bottom: clamp(16px, 2.4vw, 26px);
  padding-top: 16px;
  border-top: 1px solid var(--rule);
}

.page-about .about-block__head::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: 64px;
  height: 3px;
  background: var(--sand);
}

.page-about .about-block__index {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--sand);
}

.page-about .about-block__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(23px, 3.2vw, 34px);
  line-height: 1.24;
  letter-spacing: 0.01em;
  color: var(--ink);
}

.page-about .about-text {
  margin: 0 0 14px;
  max-width: 38em;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--char);
}

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

.page-about .about-link {
  color: var(--ink-2);
  text-decoration: none;
  border-bottom: 1px solid var(--sand);
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  color: var(--coral);
  border-bottom-color: var(--coral);
}

.page-about .about-vertnote {
  display: none;
}

/* ---------- 图注容器 ---------- */
.page-about .about-figure {
  margin: 0;
  border: 1px solid var(--rule);
  background: var(--paper-2);
  box-shadow: var(--shadow);
}

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

.page-about .about-figure figcaption {
  padding: 10px 12px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--muted);
  background: var(--paper);
  border-top: 1px solid var(--rule);
}

/* ---------- 编号章节 ---------- */
.page-about .about-code__form {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin: 0 0 clamp(18px, 2.6vw, 26px);
  padding: 10px 14px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--ink-2);
  background: var(--paper-2);
  border: 1px dashed var(--rule);
}

.page-about .about-code__joiner {
  color: var(--sand);
}

.page-about .about-code-layout {
  display: grid;
  gap: clamp(18px, 3vw, 30px);
}

.page-about .about-code {
  display: grid;
  gap: 14px;
}

.page-about .about-code__item {
  position: relative;
  padding: 16px 18px 18px;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 26px), calc(100% - 26px) 100%, 0 100%);
  transition: background 0.18s var(--ease), color 0.18s var(--ease);
}

.page-about .about-code__item:hover,
.page-about .about-code__item:focus-within {
  background: var(--ink);
}

.page-about .about-code__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--sand);
}

.page-about .about-code__name {
  margin: 6px 0 6px;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 800;
  color: var(--ink);
  transition: color 0.18s var(--ease);
}

.page-about .about-code__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--char);
  transition: color 0.18s var(--ease);
}

.page-about .about-code__hint {
  margin: 0;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mist);
  transition: max-height 0.24s var(--ease), opacity 0.24s var(--ease), margin-top 0.24s var(--ease);
}

.page-about .about-code__item:hover .about-code__name,
.page-about .about-code__item:focus-within .about-code__name {
  color: var(--paper);
}

.page-about .about-code__item:hover .about-code__desc,
.page-about .about-code__item:focus-within .about-code__desc {
  color: var(--mist);
}

.page-about .about-code__item:hover .about-code__hint,
.page-about .about-code__item:focus-within .about-code__hint {
  max-height: 4em;
  margin-top: 10px;
  opacity: 1;
}

/* ---------- 流程 ---------- */
.page-about .about-split {
  display: grid;
  gap: clamp(18px, 3vw, 32px);
}

.page-about .about-steps {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  counter-reset: step;
  display: grid;
  gap: 12px;
}

.page-about .about-steps li {
  position: relative;
  counter-increment: step;
  padding: 12px 0 0 44px;
  border-top: 1px solid var(--rule);
}

.page-about .about-steps li::before {
  content: counter(step, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 14px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--sand);
}

.page-about .about-steps__t {
  display: block;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-steps__d {
  margin: 4px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 共建节点 ---------- */
.page-about .about-nodes {
  margin-top: clamp(18px, 2.6vw, 26px);
  padding: clamp(16px, 2.6vw, 28px);
  background: var(--ink);
  border: 1px solid var(--ink-2);
}

.page-about .about-nodes svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-nodes__legend {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-nodes__legend li {
  display: flex;
  gap: 12px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .about-nodes__key {
  flex: 0 0 auto;
  min-width: 3.5em;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--signal);
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline__plate {
  margin: 0 0 clamp(20px, 3vw, 30px);
  border: 1px solid var(--rule);
  overflow: hidden;
}

.page-about .about-timeline__plate img {
  display: block;
  width: 100%;
  height: clamp(96px, 16vw, 180px);
  max-width: 100%;
  object-fit: cover;
}

.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .about-timeline li {
  position: relative;
  padding: 4px 0 0 20px;
  border-left: 1px solid var(--rule);
}

.page-about .about-timeline li::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 8px;
  width: 7px;
  height: 7px;
  background: var(--sand);
}

.page-about .about-timeline__ver {
  display: inline-block;
  padding: 3px 9px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--signal);
  background: var(--ink);
}

.page-about .about-timeline__tt {
  margin: 10px 0 6px;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-timeline__desc {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--muted);
}

/* ---------- 屏幕密度 ---------- */
.page-about .about-density {
  display: grid;
  gap: clamp(18px, 3vw, 30px);
}

.page-about .about-density__figure {
  margin: 0;
  padding: 18px 20px 20px;
  font-family: var(--font-mono);
  font-size: clamp(48px, 8vw, 84px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--ink);
  background: var(--paper-2);
  border: 1px solid var(--rule);
  border-left: 6px solid var(--signal);
}

.page-about .about-density__figure small {
  display: block;
  margin-top: 12px;
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.12em;
  line-height: 1.6;
  color: var(--muted);
}

/* ---------- 结尾 ---------- */
.page-about .about-cta {
  margin-top: clamp(40px, 6vw, 80px);
  padding: clamp(22px, 4vw, 40px);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 18px 28px;
  background: var(--ink);
  border-top: 6px solid var(--coral);
}

.page-about .about-cta h2 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(20px, 2.6vw, 28px);
  font-weight: 800;
  line-height: 1.3;
  color: var(--paper);
}

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

.page-about .about-cta .btn {
  text-decoration: none;
  white-space: nowrap;
}

.page-about .about-cta .btn--ghost {
  color: var(--paper);
  border-color: rgba(244, 238, 226, 0.45);
}

.page-about .about-cta .btn--ghost:hover,
.page-about .about-cta .btn--ghost:focus-visible {
  color: var(--ink);
  background: var(--mist);
  border-color: var(--mist);
}

/* ---------- 断点 ---------- */
@media (min-width: 760px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 860px) {
  .page-about .about-code-layout {
    grid-template-columns: minmax(0, 4fr) minmax(0, 7fr);
    align-items: start;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    align-items: start;
  }

  .page-about .about-density {
    grid-template-columns: minmax(0, 3fr) minmax(0, 7fr);
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 2fr);
    align-items: start;
  }

  .page-about .about-hero__side {
    display: block;
    justify-self: end;
    min-height: 180px;
    padding-left: 14px;
    border-left: 1px solid var(--rule);
    writing-mode: vertical-rl;
    font-size: 12px;
    letter-spacing: 0.28em;
    color: var(--muted);
  }

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

  .page-about .about-timeline li {
    padding: 22px 20px 0 0;
    border-left: 0;
    border-top: 1px solid var(--rule);
  }

  .page-about .about-timeline li::before {
    left: 0;
    top: -4px;
    width: 8px;
    height: 8px;
  }
}

@media (min-width: 1000px) {
  .page-about .about-body {
    grid-template-columns: 186px minmax(0, 1fr);
    column-gap: clamp(28px, 4vw, 56px);
    align-items: start;
  }

  .page-about .about-chapters {
    display: block;
    position: sticky;
    top: calc(var(--bar-h) + 24px);
  }
}

@media (min-width: 1200px) {
  .page-about .about-block--noted {
    padding-right: 64px;
  }

  .page-about .about-vertnote {
    display: block;
    position: absolute;
    top: 10px;
    right: 0;
    max-height: 300px;
    padding-right: 12px;
    border-right: 1px solid var(--rule);
    writing-mode: vertical-rl;
    font-size: 12px;
    letter-spacing: 0.3em;
    color: var(--muted);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-code__item,
  .page-about .about-code__hint,
  .page-about .about-code__name,
  .page-about .about-code__desc,
  .page-about .about-chapters__link,
  .page-about .about-link {
    transition: none;
  }
}

.page-about {
  --about-edge: clamp(18px, 4.5vw, 56px);
  --about-gap: clamp(22px, 4vw, 44px);
  background: var(--paper);
  color: var(--char);
  font-family: var(--font-body);
  line-height: 1.75;
}

.page-about .about-wrap {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--about-edge);
}

/* 首屏 */
.page-about .about-hero {
  border-bottom: 1px solid var(--rule);
  padding-block: clamp(20px, 4vw, 40px) clamp(26px, 4vw, 48px);
  background:
    linear-gradient(180deg, rgba(38, 224, 214, 0.07), rgba(244, 238, 226, 0) 62%),
    var(--paper);
}

.page-about .about-crumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 clamp(18px, 3vw, 32px);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--muted);
}

.page-about .about-crumb .breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  margin-right: 8px;
  color: var(--rule);
}

.page-about .about-crumb .breadcrumb__link {
  color: var(--ink-2);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.18s var(--ease);
}

.page-about .about-crumb .breadcrumb__link:hover,
.page-about .about-crumb .breadcrumb__link:focus-visible {
  border-bottom-color: var(--coral);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(16px, 3vw, 28px);
}

.page-about .about-kicker {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--sand);
}

.page-about .about-hero h1 {
  margin: 0;
  max-width: 15em;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 5.6vw, 58px);
  line-height: 1.14;
  letter-spacing: 0.01em;
  color: var(--ink);
}

.page-about .about-lede {
  margin: clamp(16px, 2.4vw, 24px) 0 0;
  max-width: 40em;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.85;
  color: var(--char);
}

.page-about .about-hero__side {
  display: none;
  margin: 0;
}

.page-about .about-stats {
  list-style: none;
  margin: clamp(24px, 3.4vw, 42px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
}

.page-about .about-stats li {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 16px 16px;
  background: var(--paper);
}

.page-about .about-stats__num {
  font-family: var(--font-mono);
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}

.page-about .about-stats__unit {
  margin-left: 2px;
  font-size: 13px;
  font-weight: 500;
  color: var(--sand);
}

.page-about .about-stats__label {
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--muted);
}

/* 主体两栏 */
.page-about .about-body {
  max-width: var(--maxw);
  margin-inline: auto;
  padding: clamp(28px, 5vw, 64px) var(--about-edge) clamp(40px, 6vw, 80px);
  display: grid;
  gap: var(--about-gap);
}

.page-about .about-chapters {
  display: none;
}

.page-about .about-chapters__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px 0;
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.page-about .about-chapters__link:hover,
.page-about .about-chapters__link:focus-visible {
  color: var(--ink);
  border-bottom-color: var(--rule);
}

.page-about .about-chapters__link.is-current {
  color: var(--ink);
  border-bottom-color: var(--sand);
}

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

.page-about .about-chapters__link.is-current .about-chapters__num {
  color: var(--coral);
}

/* 章节 */
.page-about .about-block {
  position: relative;
  scroll-margin-top: calc(var(--bar-h) + 24px);
}

.page-about .about-block + .about-block {
  margin-top: clamp(34px, 5vw, 72px);
}

.page-about .about-block__head {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px;
  margin-bottom: clamp(16px, 2.4vw, 26px);
  padding-top: 16px;
  border-top: 1px solid var(--rule);
}

.page-about .about-block__head::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: 64px;
  height: 3px;
  background: var(--sand);
}

.page-about .about-block__index {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--sand);
}

.page-about .about-block__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(23px, 3.2vw, 34px);
  line-height: 1.24;
  letter-spacing: 0.01em;
  color: var(--ink);
}

.page-about .about-text {
  margin: 0 0 14px;
  max-width: 38em;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--char);
}

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

.page-about .about-link {
  color: var(--ink-2);
  text-decoration: none;
  border-bottom: 1px solid var(--sand);
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  color: var(--coral);
  border-bottom-color: var(--coral);
}

.page-about .about-vertnote {
  display: none;
}

/* 图注容器 */
.page-about .about-figure {
  margin: 0;
  border: 1px solid var(--rule);
  background: var(--paper-2);
  box-shadow: var(--shadow);
}

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

.page-about .about-figure figcaption {
  padding: 10px 12px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--muted);
  background: var(--paper);
  border-top: 1px solid var(--rule);
}

/* 编号章节 */
.page-about .about-code__form {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin: 0 0 clamp(18px, 2.6vw, 26px);
  padding: 10px 14px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--ink-2);
  background: var(--paper-2);
  border: 1px dashed var(--rule);
}

.page-about .about-code__joiner {
  color: var(--sand);
}

.page-about .about-code-layout {
  display: grid;
  gap: clamp(18px, 3vw, 30px);
}

.page-about .about-code {
  display: grid;
  gap: 14px;
}

.page-about .about-code__item {
  position: relative;
  padding: 16px 18px 18px;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 26px), calc(100% - 26px) 100%, 0 100%);
  transition: background 0.18s var(--ease), color 0.18s var(--ease);
}

.page-about .about-code__item:hover,
.page-about .about-code__item:focus-within {
  background: var(--ink);
}

.page-about .about-code__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--sand);
}

.page-about .about-code__name {
  margin: 6px 0 6px;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 800;
  color: var(--ink);
  transition: color 0.18s var(--ease);
}

.page-about .about-code__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--char);
  transition: color 0.18s var(--ease);
}

.page-about .about-code__hint {
  margin: 0;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mist);
  transition: max-height 0.24s var(--ease), opacity 0.24s var(--ease), margin-top 0.24s var(--ease);
}

.page-about .about-code__item:hover .about-code__name,
.page-about .about-code__item:focus-within .about-code__name {
  color: var(--paper);
}

.page-about .about-code__item:hover .about-code__desc,
.page-about .about-code__item:focus-within .about-code__desc {
  color: var(--mist);
}

.page-about .about-code__item:hover .about-code__hint,
.page-about .about-code__item:focus-within .about-code__hint {
  max-height: 4em;
  margin-top: 10px;
  opacity: 1;
}

/* 流程 */
.page-about .about-split {
  display: grid;
  gap: clamp(18px, 3vw, 32px);
}

.page-about .about-steps {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  counter-reset: step;
  display: grid;
  gap: 12px;
}

.page-about .about-steps li {
  position: relative;
  counter-increment: step;
  padding: 12px 0 0 44px;
  border-top: 1px solid var(--rule);
}

.page-about .about-steps li::before {
  content: counter(step, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 14px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--sand);
}

.page-about .about-steps__t {
  display: block;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-steps__d {
  margin: 4px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

/* 共建节点 */
.page-about .about-nodes {
  margin-top: clamp(18px, 2.6vw, 26px);
  padding: clamp(16px, 2.6vw, 28px);
  background: var(--ink);
  border: 1px solid var(--ink-2);
}

.page-about .about-nodes svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-nodes__legend {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-nodes__legend li {
  display: flex;
  gap: 12px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .about-nodes__key {
  flex: 0 0 auto;
  min-width: 3.5em;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--signal);
}

/* 时间线 */
.page-about .about-timeline__plate {
  margin: 0 0 clamp(20px, 3vw, 30px);
  border: 1px solid var(--rule);
  overflow: hidden;
}

.page-about .about-timeline__plate img {
  display: block;
  width: 100%;
  height: clamp(96px, 16vw, 180px);
  max-width: 100%;
  object-fit: cover;
}

.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .about-timeline li {
  position: relative;
  padding: 4px 0 0 20px;
  border-left: 1px solid var(--rule);
}

.page-about .about-timeline li::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 8px;
  width: 7px;
  height: 7px;
  background: var(--sand);
}

.page-about .about-timeline__ver {
  display: inline-block;
  padding: 3px 9px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--signal);
  background: var(--ink);
}

.page-about .about-timeline__tt {
  margin: 10px 0 6px;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-timeline__desc {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--muted);
}

/* 屏幕密度 */
.page-about .about-density {
  display: grid;
  gap: clamp(18px, 3vw, 30px);
}

.page-about .about-density__figure {
  margin: 0;
  padding: 18px 20px 20px;
  font-family: var(--font-mono);
  font-size: clamp(48px, 8vw, 84px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--ink);
  background: var(--paper-2);
  border: 1px solid var(--rule);
  border-left: 6px solid var(--signal);
}

.page-about .about-density__figure small {
  display: block;
  margin-top: 12px;
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.12em;
  line-height: 1.6;
  color: var(--muted);
}

/* 结尾 */
.page-about .about-cta {
  margin-top: clamp(40px, 6vw, 80px);
  padding: clamp(22px, 4vw, 40px);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 18px 28px;
  background: var(--ink);
  border-top: 6px solid var(--coral);
}

.page-about .about-cta h2 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(20px, 2.6vw, 28px);
  font-weight: 800;
  line-height: 1.3;
  color: var(--paper);
}

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

.page-about .about-cta .btn {
  text-decoration: none;
  white-space: nowrap;
}

.page-about .about-cta .btn--ghost {
  color: var(--paper);
  border-color: rgba(244, 238, 226, 0.45);
}

.page-about .about-cta .btn--ghost:hover,
.page-about .about-cta .btn--ghost:focus-visible {
  color: var(--ink);
  background: var(--mist);
  border-color: var(--mist);
}

/* 断点 */
@media (min-width: 760px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 860px) {
  .page-about .about-code-layout {
    grid-template-columns: minmax(0, 4fr) minmax(0, 7fr);
    align-items: start;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    align-items: start;
  }

  .page-about .about-density {
    grid-template-columns: minmax(0, 3fr) minmax(0, 7fr);
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 2fr);
    align-items: start;
  }

  .page-about .about-hero__side {
    display: block;
    justify-self: end;
    min-height: 180px;
    padding-left: 14px;
    border-left: 1px solid var(--rule);
    writing-mode: vertical-rl;
    font-size: 12px;
    letter-spacing: 0.28em;
    color: var(--muted);
  }

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

  .page-about .about-timeline li {
    padding: 22px 20px 0 0;
    border-left: 0;
    border-top: 1px solid var(--rule);
  }

  .page-about .about-timeline li::before {
    left: 0;
    top: -4px;
    width: 8px;
    height: 8px;
  }
}

@media (min-width: 1000px) {
  .page-about .about-body {
    grid-template-columns: 186px minmax(0, 1fr);
    column-gap: clamp(28px, 4vw, 56px);
    align-items: start;
  }

  .page-about .about-chapters {
    display: block;
    position: sticky;
    top: calc(var(--bar-h) + 24px);
  }
}

@media (min-width: 1200px) {
  .page-about .about-block--noted {
    padding-right: 64px;
  }

  .page-about .about-vertnote {
    display: block;
    position: absolute;
    top: 10px;
    right: 0;
    max-height: 300px;
    padding-right: 12px;
    border-right: 1px solid var(--rule);
    writing-mode: vertical-rl;
    font-size: 12px;
    letter-spacing: 0.3em;
    color: var(--muted);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-code__item,
  .page-about .about-code__hint,
  .page-about .about-code__name,
  .page-about .about-code__desc,
  .page-about .about-chapters__link,
  .page-about .about-link {
    transition: none;
  }
}