.page-about {
  display: block;
  padding-bottom: clamp(64px, 10vw, 128px);
  color: var(--vt-text);
}

.page-about .vt-crumbs {
  padding-top: clamp(16px, 3vw, 28px);
}

/* ---------- 首屏档案刊头 ---------- */
.page-about .ab-open {
  display: grid;
  gap: 26px;
  padding-top: clamp(24px, 5vw, 48px);
  padding-bottom: clamp(40px, 8vw, 88px);
}

.page-about .ab-file {
  background: var(--vt-paper);
  color: var(--vt-paper-ink);
  padding: 18px 18px 20px;
  border-radius: 2px;
  box-shadow: 0 20px 44px rgba(0, 0, 0, 0.5);
}

.page-about .ab-file__kick {
  margin: 0 0 12px;
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(26, 23, 18, 0.55);
}

.page-about .ab-file__list {
  margin: 0;
}

.page-about .ab-file__row {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 9px 0;
  border-bottom: 1px dashed rgba(26, 23, 18, 0.22);
  font-size: 13px;
  line-height: 1.5;
}

.page-about .ab-file__row:last-child {
  border-bottom: 0;
}

.page-about .ab-file__row dt {
  color: rgba(26, 23, 18, 0.6);
  flex: 0 0 auto;
}

.page-about .ab-file__row dd {
  margin: 0;
  text-align: right;
  font-weight: 600;
}

.page-about .ab-open__kicker {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--vt-muted);
}

.page-about .ab-open__title {
  margin: 0;
  font-family: var(--vt-font-display);
  font-size: clamp(42px, 11vw, 72px);
  line-height: 1.02;
  letter-spacing: -0.02em;
  font-weight: 700;
  color: var(--vt-text);
}

.page-about .ab-open__lede {
  margin: 22px 0 0;
  max-width: 36em;
  font-size: 17px;
  line-height: 1.75;
  color: var(--vt-text);
}

.page-about .ab-open__note {
  margin: 16px 0 0;
  max-width: 36em;
  font-size: 14px;
  line-height: 1.7;
  color: var(--vt-muted);
}

.page-about .ab-rule {
  margin-top: 30px;
  height: 16px;
  border-top: 1px solid var(--vt-strong);
  background-image: repeating-linear-gradient(
    to right,
    var(--vt-grid) 0 1px,
    transparent 1px 16px
  );
  background-size: 16px 8px;
  background-repeat: repeat-x;
  background-position: 0 0;
  position: relative;
}

.page-about .ab-rule::after {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 84px;
  height: 1px;
  background: var(--vt-confirmed);
  box-shadow: 0 0 12px rgba(59, 224, 210, 0.55);
}

/* ---------- 章节骨架 ---------- */
.page-about .ab-chapter {
  padding-top: clamp(52px, 9vw, 104px);
  padding-bottom: clamp(52px, 9vw, 104px);
  border-top: 1px solid var(--vt-grid);
}

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

/* ---------- 团队构成 ---------- */
.page-about .ab-team {
  display: grid;
  gap: 26px;
  margin-top: 34px;
}

.page-about .ab-team__tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .ab-tab {
  display: block;
  padding: 9px 12px;
  border: 1px solid var(--vt-strong);
  background: rgba(11, 18, 32, 0.6);
  color: var(--vt-text);
  font-size: 13px;
  line-height: 1.3;
  text-decoration: none;
  letter-spacing: 0.02em;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.page-about .ab-tab:hover,
.page-about .ab-tab:focus-visible {
  border-color: var(--vt-confirmed);
  color: var(--vt-confirmed);
}

.page-about .ab-team__item {
  padding: 20px 0;
  border-bottom: 1px solid var(--vt-grid);
}

.page-about .ab-team__item:first-child {
  border-top: 1px solid var(--vt-grid);
}

.page-about .ab-team__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
}

.page-about .ab-team__name {
  margin: 0;
  font-size: 16px;
  letter-spacing: 0.06em;
  color: var(--vt-text);
}

.page-about .ab-team__count {
  margin: 0;
  display: inline-flex;
  align-items: baseline;
  gap: 4px;
}

.page-about .ab-team__num {
  font-family: var(--vt-font-mono);
  font-size: clamp(32px, 7vw, 52px);
  line-height: 1;
  color: var(--vt-confirmed);
  border-bottom: 3px solid var(--vt-confirmed-dim);
  padding-bottom: 4px;
}

.page-about .ab-team__unit {
  font-size: 13px;
  color: var(--vt-muted);
}

.page-about .ab-team__desc {
  margin: 12px 0 0;
  max-width: 44em;
  font-size: 15px;
  line-height: 1.75;
  color: var(--vt-muted);
}

.page-about .ab-team__figure {
  margin: 0;
}

/* ---------- 版本时间轴 ---------- */
.page-about .ab-tl__bg {
  margin: 34px 0 0;
}

.page-about .ab-tl__bg .vt-figure__img {
  opacity: 0.92;
}

.page-about .ab-tl {
  list-style: none;
  margin: 40px 0 0;
  padding: 0;
}

.page-about .ab-tl__item {
  position: relative;
  padding: 0 0 30px 28px;
  border-left: 1px solid var(--vt-grid);
}

.page-about .ab-tl__item:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.page-about .ab-tl__dot {
  position: absolute;
  left: -5px;
  top: 7px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  transition: transform 0.2s ease;
}

.page-about .ab-tl__dot--done {
  background: var(--vt-confirmed);
  box-shadow: 0 0 0 3px rgba(59, 224, 210, 0.14);
}

.page-about .ab-tl__dot--doing {
  background: var(--vt-pending);
  box-shadow: 0 0 0 3px rgba(255, 174, 71, 0.16);
}

.page-about .ab-tl__item:hover .ab-tl__dot,
.page-about .ab-tl__item:focus-within .ab-tl__dot {
  transform: scale(1.35);
}

.page-about .ab-tl__year {
  margin: 0;
  font-family: var(--vt-font-mono);
  font-size: 15px;
  letter-spacing: 0.1em;
  color: var(--vt-muted);
}

.page-about .ab-tl__title {
  margin: 4px 0 0;
  font-size: 17px;
  letter-spacing: 0.02em;
  color: var(--vt-text);
}

.page-about .ab-tl__item--doing .ab-tl__title {
  color: var(--vt-pending);
}

.page-about .ab-tl__desc {
  margin: 8px 0 0;
  max-width: 44em;
  font-size: 15px;
  line-height: 1.75;
  color: var(--vt-muted);
}

.page-about .ab-tl__out {
  margin: 0;
  font-size: 13px;
  line-height: 1.6;
  color: var(--vt-confirmed);
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height 0.32s ease, opacity 0.32s ease, margin-top 0.32s ease;
}

.page-about .ab-tl__item:hover .ab-tl__out,
.page-about .ab-tl__item:focus-within .ab-tl__out {
  max-height: 80px;
  opacity: 1;
  margin-top: 10px;
}

/* ---------- 可验证原则 ---------- */
.page-about .ab-code {
  list-style: none;
  margin: 36px 0 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .ab-code__item {
  border: 1px solid var(--vt-strong);
  box-shadow: inset 0 0 0 4px var(--vt-base), inset 0 0 0 5px var(--vt-grid);
  background: linear-gradient(180deg, rgba(11, 18, 32, 0.92), rgba(5, 7, 12, 0.92));
  padding: 26px 20px 22px;
}

.page-about .ab-code__idx {
  margin: 0;
  font-family: var(--vt-font-mono);
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--vt-confirmed-dim);
}

.page-about .ab-seal {
  display: inline-block;
  margin-top: 10px;
  padding: 3px 8px;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--vt-confirmed);
  border: 1px solid var(--vt-confirmed-dim);
  transform: rotate(-1.5deg);
}

.page-about .ab-code__title {
  margin: 14px 0 0;
  font-size: 20px;
  letter-spacing: 0.02em;
  color: var(--vt-text);
}

.page-about .ab-code__text {
  margin: 10px 0 0;
  max-width: 40em;
  font-size: 15px;
  line-height: 1.75;
  color: var(--vt-muted);
}

.page-about .ab-code__where {
  margin: 14px 0 0;
  font-size: 13px;
}

.page-about .ab-code__link {
  color: var(--vt-confirmed);
  text-decoration: none;
  border-bottom: 1px solid var(--vt-confirmed-dim);
  padding-bottom: 2px;
}

.page-about .ab-code__link:hover,
.page-about .ab-code__link:focus-visible {
  color: var(--vt-text);
  border-bottom-color: var(--vt-confirmed);
}

/* ---------- 本地服务 ---------- */
.page-about .ab-local {
  display: grid;
  gap: 24px;
  margin-top: 34px;
}

.page-about .ab-local__figure {
  margin: 0;
}

.page-about .ab-local__text {
  margin: 0 0 14px;
  max-width: 40em;
  font-size: 15px;
  line-height: 1.75;
  color: var(--vt-muted);
}

.page-about .ab-local__list {
  list-style: none;
  margin: 0 0 16px;
  padding: 0;
  border-top: 1px solid var(--vt-grid);
}

.page-about .ab-local__list li {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 14px;
  padding: 12px 0;
  border-bottom: 1px solid var(--vt-grid);
}

.page-about .ab-local__key {
  flex: 0 0 auto;
  font-size: 13px;
  color: var(--vt-confirmed);
}

.page-about .ab-local__val {
  flex: 1 1 200px;
  font-size: 14px;
  line-height: 1.65;
  color: var(--vt-muted);
}

.page-about .ab-local__where {
  margin: 0;
  font-size: 13px;
}

/* ---------- 归档与查阅 ---------- */
.page-about .ab-archive {
  display: grid;
  gap: 26px;
  margin-top: 34px;
}

.page-about .ab-archive__facts {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--vt-grid);
}

.page-about .ab-archive__fact {
  display: flex;
  align-items: baseline;
  gap: 16px;
  padding: 16px 0;
  border-bottom: 1px solid var(--vt-grid);
}

.page-about .ab-archive__num {
  flex: 0 0 auto;
  min-width: 2.4em;
  font-size: clamp(28px, 6vw, 42px);
  line-height: 1;
  color: var(--vt-hl, var(--vt-confirmed));
}

.page-about .ab-archive__label {
  font-size: 14px;
  line-height: 1.7;
  color: var(--vt-muted);
}

.page-about .ab-archive__note {
  padding: 24px 22px 26px;
  color: var(--vt-paper-ink);
  border-radius: 2px;
}

.page-about .ab-archive__notetitle {
  margin: 0;
  font-size: 13px;
  letter-spacing: 0.16em;
  color: rgba(26, 23, 18, 0.6);
}

.page-about .ab-archive__notetext {
  margin: 12px 0 18px;
  font-size: 14px;
  line-height: 1.75;
}

.page-about .ab-archive__btn {
  display: inline-block;
}

/* ---------- 后续入口 ---------- */
.page-about .ab-next {
  display: grid;
  gap: 14px;
  margin-top: 46px;
  padding-top: 30px;
  border-top: 1px solid var(--vt-strong);
}

.page-about .ab-next__item {
  display: block;
  padding: 18px 18px 20px;
  border: 1px solid var(--vt-grid);
  background: rgba(11, 18, 32, 0.55);
  text-decoration: none;
  transition: border-color 0.2s ease, background 0.2s ease;
}

.page-about .ab-next__item:hover,
.page-about .ab-next__item:focus-visible {
  border-color: var(--vt-confirmed);
  background: rgba(20, 134, 127, 0.12);
}

.page-about .ab-next__label {
  display: block;
  font-size: 15px;
  letter-spacing: 0.06em;
  color: var(--vt-text);
}

.page-about .ab-next__hint {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--vt-muted);
}

/* ---------- 响应式 ---------- */
@media (min-width: 880px) {
  .page-about .ab-open {
    grid-template-columns: minmax(0, 240px) minmax(0, 1fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .ab-local {
    grid-template-columns: 320px minmax(0, 1fr);
    gap: 44px;
    align-items: start;
  }

  .page-about .ab-archive {
    grid-template-columns: minmax(0, 1fr) 340px;
    gap: 44px;
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about .ab-team {
    grid-template-columns: 170px minmax(0, 1fr) 288px;
    gap: 40px;
    align-items: start;
  }

  .page-about .ab-team__tabs {
    flex-direction: column;
    flex-wrap: nowrap;
  }

  .page-about .ab-code {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px;
  }

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

@media (min-width: 1080px) {
  .page-about .ab-tl {
    margin-top: 48px;
  }

  .page-about .ab-tl__item {
    display: grid;
    grid-template-columns: 96px minmax(0, 1fr);
    gap: 0 24px;
    padding-left: 34px;
    padding-bottom: 34px;
  }

  .page-about .ab-tl__year {
    grid-column: 1;
    padding-top: 2px;
  }

  .page-about .ab-tl__body {
    grid-column: 2;
  }
}

@media (hover: none) {
  .page-about .ab-tl__out {
    max-height: none;
    opacity: 1;
    margin-top: 10px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-tl__out,
  .page-about .ab-tl__dot,
  .page-about .ab-tab,
  .page-about .ab-next__item {
    transition: none;
  }
}

.page-about {
  --vt-hl: currentColor;
}