.page-about {
  --ab-cut: 18px;
  --ab-cut-sm: 11px;
  --ab-rail: 268px;
  position: relative;
  padding-bottom: 84px;
  background-color: var(--ink-900);
  background-image:
    radial-gradient(900px 540px at 92% -8%, rgba(200, 255, 77, .09), transparent 62%),
    radial-gradient(760px 480px at -12% 42%, rgba(255, 138, 61, .07), transparent 64%);
  background-repeat: no-repeat;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  padding: 10px 0 0;
}

.page-about .ab-hero__inner {
  display: grid;
  gap: 30px;
  align-items: center;
  padding: 18px 0 34px;
}

.page-about .ab-hero__copy {
  min-width: 0;
}

.page-about h1 {
  margin: 14px 0 0;
  font-size: clamp(1.78rem, 7vw, 3rem);
  line-height: 1.14;
  font-weight: 700;
  letter-spacing: -.015em;
  color: var(--text);
}

.page-about .ab-hero__lead {
  margin: 18px 0 0;
  max-width: 58ch;
  font-size: 1.02rem;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .ab-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

/* 记分牌视觉 */
.page-about .ab-board {
  position: relative;
  overflow: hidden;
  max-width: 480px;
  padding: 24px 24px 26px;
  border: var(--edge);
  background: linear-gradient(158deg, var(--ink-800) 0%, var(--ink-850) 62%, #08201a 100%);
  box-shadow: var(--shadow);
  clip-path: polygon(var(--ab-cut) 0, 100% 0, 100% calc(100% - var(--ab-cut)), calc(100% - var(--ab-cut)) 100%, 0 100%, 0 var(--ab-cut));
}

.page-about .ab-board::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: repeating-linear-gradient(115deg, rgba(200, 255, 77, .06) 0 1px, transparent 1px 16px);
}

.page-about .ab-board__top {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.page-about .ab-board__label {
  font-family: var(--font-num);
  font-size: .74rem;
  font-weight: 600;
  letter-spacing: .24em;
  color: var(--muted);
}

.page-about .ab-board__cert {
  padding: 4px 9px;
  border: 1px solid rgba(200, 255, 77, .45);
  font-size: .72rem;
  font-weight: 600;
  letter-spacing: .04em;
  color: var(--lime);
}

.page-about .ab-board__year {
  position: relative;
  margin: 16px 0 0;
  font-family: var(--font-num);
  font-size: clamp(3.2rem, 15vw, 5.4rem);
  font-weight: 700;
  line-height: .92;
  letter-spacing: -.03em;
  color: var(--lime);
}

.page-about .ab-board__sub {
  position: relative;
  margin: 8px 0 0;
  font-size: .86rem;
  letter-spacing: .02em;
  color: var(--muted);
}

.page-about .ab-board__rows {
  position: relative;
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-board__rows li {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding: 10px 0;
  border-top: 1px solid var(--ink-700);
}

.page-about .ab-board__key {
  font-size: .84rem;
  color: var(--muted);
}

.page-about .ab-board__val {
  font-family: var(--font-num);
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--orange);
}

/* 首屏数据条 */
.page-about .ab-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--ink-700);
  border: var(--edge);
  clip-path: polygon(var(--ab-cut) 0, 100% 0, 100% calc(100% - var(--ab-cut)), calc(100% - var(--ab-cut)) 100%, 0 100%, 0 var(--ab-cut));
}

.page-about .ab-stats li {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 18px 20px;
  background: var(--ink-850);
}

.page-about .ab-stats__num {
  font-family: var(--font-num);
  font-size: clamp(1.6rem, 6vw, 2.1rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--lime);
}

.page-about .ab-stats__label {
  font-size: .8rem;
  letter-spacing: .04em;
  color: var(--muted);
}

/* ---------- 时间轴 + 叙事主体 ---------- */
.page-about .ab-body {
  display: grid;
  grid-template-columns: 1fr;
  gap: 34px;
  margin-top: 46px;
}

.page-about .ab-rail {
  position: relative;
  overflow: hidden;
  padding: 18px 16px 20px;
  border: var(--edge);
  background: var(--ink-850);
  clip-path: polygon(var(--ab-cut) 0, 100% 0, 100% calc(100% - var(--ab-cut)), calc(100% - var(--ab-cut)) 100%, 0 100%, 0 var(--ab-cut));
}

.page-about .ab-rail__bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  overflow: hidden;
  opacity: .16;
  pointer-events: none;
}

.page-about .ab-rail__bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(.35) contrast(1.1);
}

.page-about .ab-rail__caption {
  position: relative;
  z-index: 1;
  margin: 0 0 12px;
  font-family: var(--font-num);
  font-size: .72rem;
  font-weight: 600;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .ab-timeline {
  position: relative;
  z-index: 1;
  display: flex;
  gap: 12px;
  margin: 0;
  padding: 0 2px 8px;
  list-style: none;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .ab-timeline__item {
  flex: 0 0 auto;
  width: 214px;
  padding: 14px 14px 16px;
  border: 1px solid var(--ink-700);
  background: rgba(7, 26, 21, .72);
  transition: border-color .25s var(--ease), background .25s var(--ease), transform .25s var(--ease);
}

.page-about .ab-timeline__dot {
  display: inline-block;
  width: 9px;
  height: 9px;
  margin-right: 8px;
  vertical-align: middle;
  background: var(--lime);
  clip-path: polygon(50% 0, 100% 50%, 50% 100%, 0 50%);
}

.page-about .ab-timeline__item--now .ab-timeline__dot {
  background: var(--orange);
}

.page-about .ab-timeline__year {
  font-family: var(--font-num);
  font-size: 1.02rem;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--lime);
}

.page-about .ab-timeline__item--now .ab-timeline__year {
  color: var(--orange);
}

.page-about .ab-timeline__label {
  display: block;
  margin-top: 6px;
  font-size: .95rem;
  font-weight: 600;
  color: var(--text);
}

.page-about .ab-timeline__hint {
  display: block;
  margin-top: 8px;
  font-size: .82rem;
  line-height: 1.68;
  color: var(--muted);
}

/* 叙事流 */
.page-about .ab-flow {
  display: grid;
  gap: 30px;
  min-width: 0;
}

.page-about .ab-chapter {
  min-width: 0;
}

.page-about .ab-chapter__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.page-about .ab-chapter__idx {
  flex: 0 0 auto;
  font-family: var(--font-num);
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -.02em;
  color: var(--dim);
}

.page-about .ab-chapter h2 {
  margin: 0;
  font-size: clamp(1.32rem, 4.6vw, 1.88rem);
  line-height: 1.3;
  font-weight: 700;
  color: var(--text);
}

.page-about .ab-chapter p {
  margin: 14px 0 0;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--text);
}

.page-about .ab-chapter--plain {
  padding-left: 18px;
  border-left: 3px solid var(--lime);
}

.page-about .ab-chapter--panel {
  padding: 24px 20px 26px;
  border: var(--edge);
  background: linear-gradient(180deg, var(--ink-800) 0%, var(--ink-850) 88%);
  clip-path: polygon(var(--ab-cut) 0, 100% 0, 100% calc(100% - var(--ab-cut)), calc(100% - var(--ab-cut)) 100%, 0 100%, 0 var(--ab-cut));
}

.page-about .ab-chapter .media-frame {
  margin: 20px 0 0;
}

/* 校对步骤折叠 */
.page-about .ab-steps {
  margin-top: 22px;
  border-top: 1px solid var(--ink-700);
}

.page-about .ab-steps details {
  border-bottom: 1px solid var(--ink-700);
}

.page-about .ab-steps summary {
  position: relative;
  padding: 14px 34px 14px 0;
  cursor: pointer;
  list-style: none;
  font-size: .97rem;
  font-weight: 600;
  color: var(--text);
  transition: color .22s var(--ease);
}

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

.page-about .ab-steps summary::after {
  content: "+";
  position: absolute;
  right: 4px;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-num);
  font-size: 1.15rem;
  color: var(--lime);
}

.page-about .ab-steps details[open] summary::after {
  content: "–";
}

.page-about .ab-steps summary:hover,
.page-about .ab-steps summary:focus-visible {
  color: var(--lime);
}

.page-about .ab-steps__body {
  padding: 0 0 16px;
  max-width: 62ch;
  font-size: .92rem;
  line-height: 1.8;
  color: var(--muted);
}

/* 团队分工 */
.page-about .ab-team {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-team__card {
  position: relative;
  padding: 20px 18px 22px;
  border: 1px solid var(--ink-700);
  background: var(--ink-850);
  clip-path: polygon(var(--ab-cut-sm) 0, 100% 0, 100% calc(100% - var(--ab-cut-sm)), calc(100% - var(--ab-cut-sm)) 100%, 0 100%, 0 var(--ab-cut-sm));
  transition: transform .25s var(--ease), background .25s var(--ease);
}

.page-about .ab-team__card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 40px;
  height: 3px;
  background: var(--lime);
  opacity: .45;
  transition: width .3s var(--ease), opacity .3s var(--ease);
}

.page-about .ab-team__card:hover,
.page-about .ab-team__card:focus-within {
  transform: translateY(-3px);
  background: #0d2a22;
}

.page-about .ab-team__card:hover::before,
.page-about .ab-team__card:focus-within::before {
  width: 100%;
  opacity: 1;
}

.page-about .ab-team__num {
  display: block;
  font-family: var(--font-num);
  font-size: 2.35rem;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.03em;
  color: var(--lime);
}

.page-about .ab-team__role {
  display: block;
  margin-top: 8px;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
}

.page-about .ab-team__detail {
  display: block;
  margin-top: 10px;
  font-size: .87rem;
  line-height: 1.72;
  color: var(--muted);
}

.page-about .ab-team__more {
  display: block;
  margin-top: 0;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  font-size: .85rem;
  line-height: 1.72;
  color: var(--link);
  transition: max-height .3s var(--ease), opacity .3s var(--ease), margin-top .3s var(--ease);
}

.page-about .ab-team__card:hover .ab-team__more,
.page-about .ab-team__card:focus-within .ab-team__more {
  max-height: 6em;
  margin-top: 10px;
  opacity: 1;
}

/* 五个板块 */
.page-about .ab-blocks {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
  background: var(--ink-700);
  border: var(--edge);
  clip-path: polygon(var(--ab-cut) 0, 100% 0, 100% calc(100% - var(--ab-cut)), calc(100% - var(--ab-cut)) 100%, 0 100%, 0 var(--ab-cut));
}

.page-about .ab-blocks li {
  padding: 18px 18px 20px;
  background: var(--ink-850);
}

.page-about .ab-blocks__no {
  font-family: var(--font-num);
  font-size: .74rem;
  font-weight: 600;
  letter-spacing: .18em;
  color: var(--orange);
}

.page-about .ab-blocks h3 {
  margin: 8px 0 0;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text);
}

.page-about .ab-blocks p {
  margin: 8px 0 0;
  font-size: .88rem;
  line-height: 1.72;
  color: var(--muted);
}

/* 版本演进 */
.page-about .ab-versions__wrap {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin-top: 22px;
}

.page-about .ab-versions__wrap .media-frame {
  margin: 0;
}

.page-about .ab-versions {
  display: grid;
  gap: 12px;
}

.page-about .ab-versions__item {
  padding: 16px 16px 18px;
  border: 1px solid var(--ink-700);
  border-left: 3px solid var(--orange);
  background: rgba(11, 35, 28, .6);
  transition: border-left-color .25s var(--ease), background .25s var(--ease);
}

.page-about .ab-versions__item:hover {
  border-left-color: var(--lime);
  background: rgba(15, 44, 36, .9);
}

.page-about .ab-versions__tag {
  display: block;
  font-family: var(--font-num);
  font-size: .78rem;
  font-weight: 600;
  letter-spacing: .1em;
  color: var(--orange);
}

.page-about .ab-versions__item h3 {
  margin: 8px 0 0;
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--text);
}

.page-about .ab-versions__item p {
  margin: 8px 0 0;
  font-size: .88rem;
  line-height: 1.72;
  color: var(--muted);
}

.page-about .ab-note {
  margin-top: 20px !important;
  padding-left: 14px;
  border-left: 2px solid var(--link);
  font-size: .9rem !important;
  line-height: 1.78 !important;
  color: var(--muted) !important;
}

/* ---------- 收尾入口 ---------- */
.page-about .ab-cta {
  margin-top: 62px;
}

.page-about .ab-cta__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
  padding: 30px 22px 32px;
  border: 1px solid rgba(200, 255, 77, .28);
  background:
    linear-gradient(118deg, rgba(200, 255, 77, .1) 0%, rgba(255, 138, 61, .09) 58%, rgba(7, 26, 21, 0) 100%),
    var(--ink-850);
  clip-path: polygon(var(--ab-cut) 0, 100% 0, 100% calc(100% - var(--ab-cut)), calc(100% - var(--ab-cut)) 100%, 0 100%, 0 var(--ab-cut));
}

.page-about .ab-cta__copy h2 {
  margin: 0;
  font-size: clamp(1.28rem, 4.6vw, 1.72rem);
  line-height: 1.32;
  font-weight: 700;
  color: var(--text);
}

.page-about .ab-cta__copy p {
  margin: 12px 0 0;
  max-width: 62ch;
  font-size: .95rem;
  line-height: 1.82;
  color: var(--muted);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .ab-team {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

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

  .page-about .ab-blocks li:last-child {
    grid-column: 1 / -1;
  }

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

  .page-about .ab-versions__wrap {
    grid-template-columns: minmax(0, .8fr) minmax(0, 1.2fr);
    align-items: start;
  }
}

@media (min-width: 860px) {
  .page-about .ab-cta__inner {
    grid-template-columns: minmax(0, 1.5fr) auto;
    align-items: center;
    padding: 38px 40px;
  }
}

@media (min-width: 920px) {
  .page-about .ab-hero__inner {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
    gap: 46px;
    padding: 32px 0 44px;
  }

  .page-about .ab-board {
    margin-left: auto;
  }

  .page-about .ab-chapter--panel {
    padding: 30px 28px 32px;
  }
}

@media (min-width: 1000px) {
  .page-about .ab-body {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: 46px;
    margin-top: 58px;
  }

  .page-about .ab-rail {
    position: sticky;
    top: calc(var(--topbar-h) + 24px);
    align-self: start;
    padding: 22px 18px 24px;
  }

  .page-about .ab-timeline {
    display: block;
    padding: 0;
    overflow: visible;
  }

  .page-about .ab-timeline::before {
    content: "";
    position: absolute;
    left: 5px;
    top: 8px;
    bottom: 10px;
    width: 2px;
    background: linear-gradient(180deg, var(--lime) 0%, var(--orange) 62%, var(--dim) 100%);
    opacity: .45;
  }

  .page-about .ab-timeline__item {
    position: relative;
    width: auto;
    padding: 0 0 24px 26px;
    border: 0;
    background: none;
  }

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

  .page-about .ab-timeline__dot {
    position: absolute;
    left: 1px;
    top: 6px;
    width: 10px;
    height: 10px;
    margin: 0;
    background: var(--ink-900);
    border: 2px solid var(--lime);
    border-radius: 50%;
    clip-path: none;
    transition: background .25s var(--ease), transform .25s var(--ease);
  }

  .page-about .ab-timeline__item--now .ab-timeline__dot {
    background: var(--ink-900);
    border-color: var(--orange);
  }

  .page-about .ab-timeline__item:hover .ab-timeline__dot,
  .page-about .ab-timeline__item:focus-within .ab-timeline__dot {
    background: var(--lime);
    transform: scale(1.25);
  }

  .page-about .ab-timeline__item--now:hover .ab-timeline__dot {
    background: var(--orange);
  }

  .page-about .ab-timeline__label {
    transition: color .22s var(--ease);
  }

  .page-about .ab-timeline__item:hover .ab-timeline__label {
    color: var(--lime);
  }

  .page-about .ab-timeline__hint {
    max-height: 0;
    margin-top: 0;
    overflow: hidden;
    opacity: 0;
    transition: max-height .3s var(--ease), opacity .3s var(--ease), margin-top .3s var(--ease);
  }

  .page-about .ab-timeline__item:hover .ab-timeline__hint,
  .page-about .ab-timeline__item:focus-within .ab-timeline__hint {
    max-height: 8em;
    margin-top: 8px;
    opacity: 1;
  }

  .page-about .ab-team__card:hover,
  .page-about .ab-team__card:focus-within {
    border-color: rgba(200, 255, 77, .5);
  }
}

@media (max-width: 999px) {
  .page-about .ab-rail__bg {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-team__card,
  .page-about .ab-timeline__item,
  .page-about .ab-versions__item,
  .page-about .ab-timeline__dot,
  .page-about .ab-timeline__hint,
  .page-about .ab-team__more {
    transition: none;
  }
}