.page-about {
  --about-node: 38px;
  --about-indent: calc(var(--about-node) + 22px);
  padding-bottom: clamp(48px, 8vw, 88px);
}

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

.page-about .about-block {
  margin: 0 0 clamp(40px, 6vw, 64px);
}

/* ---------- 首屏：主题声明 + 分层目录 ---------- */
.page-about .about-intro {
  max-width: 860px;
  padding-top: 6px;
  margin-bottom: clamp(26px, 4vw, 40px);
}

.page-about .about-intro__kicker {
  font-family: var(--font-editorial);
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--cyan);
  margin: 0 0 12px;
}

.page-about h1 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(32px, 6.4vw, 44px);
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--text);
  margin: 0 0 16px;
}

.page-about .about-intro .lead {
  max-width: 720px;
}

.page-about .about-map {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-map a {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  grid-template-areas:
    "num label"
    "num desc";
  column-gap: 12px;
  row-gap: 2px;
  padding: 14px 16px;
  background: var(--rail-bg);
  color: var(--text);
  text-decoration: none;
  transition: background 0.18s ease, box-shadow 0.18s ease;
}

.page-about .about-map a:hover,
.page-about .about-map a:focus-visible {
  background: var(--slab);
  box-shadow: inset 3px 0 0 var(--cyan);
  outline: none;
}

.page-about .about-map__num {
  grid-area: num;
  font-size: 13px;
  color: var(--cyan);
  padding-top: 3px;
}

.page-about .about-map__label {
  grid-area: label;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16px;
  letter-spacing: -0.01em;
}

.page-about .about-map__desc {
  grid-area: desc;
  font-size: 13px;
  color: var(--text-mute);
  line-height: 1.6;
}

/* ---------- 顶部横幅 ---------- */
.page-about .about-banner {
  margin: 0 0 clamp(40px, 6vw, 64px);
}

.page-about .about-banner .media__frame {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--rail-bg);
}

/* ---------- 时间轴区 ---------- */
.page-about .about-timeline {
  display: grid;
  gap: clamp(24px, 4vw, 34px);
  margin-top: 26px;
}

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

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: calc(var(--about-node) / 2 - 1px);
  top: 16px;
  bottom: 16px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(180deg, var(--cyan) 0%, var(--violet) 52%, var(--orange) 100%);
  opacity: 0.45;
}

.page-about .timeline__item {
  position: relative;
  padding: 0 0 26px var(--about-indent);
  outline: none;
}

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

.page-about .timeline__node {
  position: absolute;
  left: 0;
  top: 0;
  width: var(--about-node);
  height: var(--about-node);
  display: grid;
  place-items: center;
  border-radius: 50%;
  border: 1px solid var(--line);
  background: var(--rail-bg);
  color: var(--text-dim);
  font-size: 13px;
  letter-spacing: 0.02em;
  transition: color 0.18s ease, background 0.18s ease, border-color 0.18s ease, box-shadow 0.18s ease;
}

.page-about .timeline__item:hover .timeline__node,
.page-about .timeline__item:focus-visible .timeline__node,
.page-about .timeline__item:focus-within .timeline__node {
  color: var(--void);
  background: var(--cyan);
  border-color: var(--cyan);
  box-shadow: 0 0 0 4px rgba(47, 227, 200, 0.14);
}

.page-about .timeline__item:focus-visible {
  outline: none;
}

.page-about .timeline__body {
  padding-top: 4px;
}

.page-about .timeline__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18px;
  line-height: 1.45;
  letter-spacing: -0.01em;
  color: var(--text);
  margin: 0 0 8px;
}

.page-about .timeline__summary {
  margin: 0 0 10px;
  font-size: 15px;
  line-height: 1.78;
  color: var(--text-dim);
}

.page-about .timeline__meta {
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

/* ---------- 奶油纸旁注列 ---------- */
.page-about .about-notes {
  display: grid;
  gap: 14px;
  align-content: start;
}

.page-about .about-notes .media {
  margin: 0;
}

.page-about .about-notes .media__frame {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--rail-bg);
}

.page-about .about-notes .media__caption {
  margin-top: 8px;
  font-size: 12.5px;
  line-height: 1.65;
  color: var(--text-mute);
}

/* ---------- 三层核对 ---------- */
.page-about .about-sources .prose p:first-child {
  margin-top: 0;
}

.page-about .layers {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .layers__item {
  background: var(--rail-bg);
  border: 1px solid var(--line);
  border-left: 3px solid var(--cyan);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 16px 18px;
}

.page-about .layers__item:nth-child(2) {
  border-left-color: var(--violet);
}

.page-about .layers__item:nth-child(3) {
  border-left-color: var(--orange);
}

.page-about .layers__num {
  margin: 0 0 8px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--softer, var(--text-mute));
}

.page-about .layers__item:nth-child(1) .layers__num {
  color: var(--cyan);
}

.page-about .layers__item:nth-child(2) .layers__num {
  color: var(--violet);
}

.page-about .layers__item:nth-child(3) .layers__num {
  color: var(--orange);
}

.page-about .layers__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 17px;
  color: var(--text);
  margin: 0 0 6px;
}

.page-about .layers__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-dim);
}

.page-about .about-sources .fold {
  margin-top: 20px;
}

.page-about .about-sources .steps {
  margin-top: 4px;
}

/* ---------- 维护分工 ---------- */
.page-about .team {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .team__item {
  background: var(--void);
  padding: 20px 18px 22px;
  transition: background 0.18s ease;
}

.page-about .team__item:hover {
  background: var(--rail-bg);
}

.page-about .team__num {
  font-family: var(--font-mono);
  font-size: 34px;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--orange);
  margin: 0 0 14px;
}

.page-about .team__item:nth-child(even) .team__num {
  color: var(--cyan);
}

.page-about .team__unit {
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--text-mute);
}

.page-about .team__role {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16px;
  color: var(--text);
  margin: 0 0 8px;
}

.page-about .team__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--text-dim);
}

.page-about .about-team-note {
  margin-top: 24px;
  max-width: 780px;
}

/* ---------- 术语表 ---------- */
.page-about .about-glossary .glossary {
  margin: 26px 0 0;
}

.page-about .glossary__row {
  display: grid;
  gap: 6px 22px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .glossary__row:first-child {
  border-top: 1px solid var(--line-soft);
}

.page-about .glossary__term {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16px;
  line-height: 1.4;
  color: var(--text);
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px;
}

.page-about .glossary__en {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .glossary__def {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--text-dim);
}

.page-about .glossary__link {
  display: inline-block;
  margin-left: 6px;
  font-size: 13px;
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(47, 227, 200, 0.36);
  white-space: nowrap;
  transition: color 0.18s ease, border-color 0.18s ease;
}

.page-about .glossary__link:hover,
.page-about .glossary__link:focus-visible {
  color: var(--text);
  border-bottom-color: var(--text);
  outline: none;
}

/* ---------- 参与与共建 ---------- */
.page-about .credits {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .credits__item {
  position: relative;
  background: var(--rail-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 20px;
  transition: border-color 0.18s ease, background 0.18s ease;
}

.page-about .credits__item:hover {
  border-color: var(--cyan);
  background: var(--slab);
}

.page-about .credits__label {
  margin: 0 0 8px;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--orange);
}

.page-about .credits__title {
  font-family: var(--font-editorial);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.5;
  color: var(--text);
  margin: 0 0 8px;
}

.page-about .credits__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-dim);
}

/* ---------- 使用边界 ---------- */
.page-about .about-boundary {
  margin-top: 26px;
}

.page-about .boundary-list {
  margin: 14px 0 0;
  padding: 0 0 0 18px;
  display: grid;
  gap: 10px;
}

.page-about .boundary-list li {
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-dim);
}

.page-about .boundary-list li::marker {
  color: var(--errata);
}

.page-about .about-boundary-note {
  margin-top: 26px;
  max-width: 780px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-map {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 720px) {
  .page-about .team {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .glossary__row {
    grid-template-columns: minmax(0, 200px) minmax(0, 1fr);
    align-items: baseline;
    padding: 16px 0;
  }

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

@media (min-width: 960px) {
  .page-about {
    --about-node: 42px;
  }

  .page-about .about-timeline {
    grid-template-columns: minmax(0, 1fr) 296px;
    align-items: start;
  }

  .page-about .about-notes {
    position: sticky;
    top: calc(var(--sync-h) + 20px);
  }

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

@media (min-width: 1080px) {
  .page-about .about-map {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .timeline__title {
    font-size: 19px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-map a,
  .page-about .timeline__node,
  .page-about .team__item,
  .page-about .credits__item,
  .page-about .glossary__link {
    transition: none;
  }
}
</style>

.page-about {
  --softer: currentColor;
}