.page-about {
  --ab-ln: rgba(217, 207, 191, .2);
  --ab-ln-soft: rgba(217, 207, 191, .1);
  --ab-line-cyan: rgba(63, 224, 200, .3);
  --ab-body: #C6D6D1;
  --ab-body-soft: #AFC4BE;
  background: var(--ink);
  color: var(--bone);
  font-family: var(--font-body);
  padding-top: clamp(104px, 16vh, 168px);
  overflow-x: clip;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  margin-bottom: clamp(28px, 5vw, 52px);
}

/* ---------- 章节题头 ---------- */
.page-about .ab-hero {
  position: relative;
  padding: 0 0 clamp(38px, 6vw, 68px);
  isolation: isolate;
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 26% -14% auto -14%;
  height: 1px;
  background: linear-gradient(90deg, transparent 0%, rgba(63, 224, 200, .42) 32%, rgba(255, 90, 46, .3) 76%, transparent 100%);
  transform: rotate(-3.6deg);
  z-index: -1;
  pointer-events: none;
}

.page-about .ab-hero__grid {
  display: grid;
  gap: clamp(18px, 3vw, 32px);
}

.page-about .ab-hero__kicker {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 16px;
}

.page-about .ab-hero__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(42px, 11vw, 118px);
  line-height: .94;
  letter-spacing: -.02em;
  color: var(--bone);
}

.page-about .ab-hero__lead {
  margin: 0;
  max-width: 54ch;
  font-size: clamp(15px, 1.5vw, 17.5px);
  line-height: 1.85;
  color: var(--ab-body-soft);
}

.page-about .ab-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 6px 0 0;
  padding: 0;
  background: var(--ab-ln);
  border-top: 1px solid var(--ab-ln);
  border-bottom: 1px solid var(--ab-ln);
}

.page-about .ab-fact {
  background: var(--ink);
  padding: 16px 14px 16px 0;
}

.page-about .ab-fact dt {
  font-size: var(--index-size);
  letter-spacing: var(--index-track);
  color: var(--mist);
}

.page-about .ab-fact dd {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  font-size: clamp(20px, 3vw, 28px);
  line-height: 1;
  color: var(--cyan);
}

.page-about .ab-fact__u {
  font-size: .5em;
  font-weight: 400;
  letter-spacing: 0;
  color: var(--mist);
  margin-left: .4em;
}

/* ---------- 章节通用 ---------- */
.page-about .ab-chapter {
  position: relative;
  padding: clamp(40px, 6vw, 80px) 0;
}

.page-about .ab-chapter::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: var(--ab-ln-soft);
  transform: translateX(clamp(4px, 1vw, 12px));
}

.page-about .ab-chapter__inner {
  display: grid;
  gap: clamp(14px, 2.6vw, 26px);
}

.page-about .ab-chapter__side {
  display: flex;
  align-items: center;
  gap: 14px;
}

.page-about .ab-chapter__no {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 13px;
  letter-spacing: .12em;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-chapter__side::after {
  content: "";
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, var(--ab-line-cyan), transparent);
}

.page-about .ab-chapter__title {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(26px, 4.4vw, 44px);
  line-height: 1.14;
  letter-spacing: -.01em;
  color: var(--bone);
}

.page-about .ab-chapter__intro {
  margin: 0 0 22px;
  max-width: 62ch;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.85;
  color: var(--ab-body);
}

.page-about .ab-chapter__body .prose p {
  margin: 0 0 1.4em;
  max-width: 68ch;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.8;
  color: var(--ab-body);
}

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

.page-about .ab-chapter__note {
  margin: 26px 0 0;
  padding-left: 16px;
  border-left: 1px solid var(--ab-line-cyan);
  max-width: 34ch;
  font-size: 13px;
  line-height: 1.78;
  color: var(--mist);
}

/* ---------- 维度折叠条目 ---------- */
.page-about .ab-dim {
  border-top: 1px solid var(--ab-ln);
}

.page-about .ab-dim:last-of-type {
  border-bottom: 1px solid var(--ab-ln);
}

.page-about .ab-dim__sum {
  display: flex;
  align-items: baseline;
  gap: 12px;
  position: relative;
  padding: 16px 34px 16px 0;
  cursor: pointer;
  list-style: none;
  color: var(--bone);
  transition: color .2s var(--ease);
}

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

.page-about .ab-dim__sum:hover,
.page-about .ab-dim__sum:focus-visible {
  color: var(--cyan);
}

.page-about .ab-dim__sum::after {
  content: "+";
  position: absolute;
  right: 6px;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--cyan);
}

.page-about .ab-dim[open] .ab-dim__sum::after {
  content: "–";
}

.page-about .ab-dim__no {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--mist);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-dim__name {
  font-size: clamp(16px, 1.9vw, 19px);
  font-weight: 500;
  letter-spacing: .02em;
}

.page-about .ab-dim__hint {
  margin-left: auto;
  font-size: 11px;
  letter-spacing: var(--index-track);
  color: var(--flame);
}

.page-about .ab-dim__body {
  padding: 0 0 20px 0;
  max-width: 68ch;
}

.page-about .ab-dim__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ab-body-soft);
}

.page-about .ab-outscope {
  margin: 28px 0 0;
  padding: 20px 18px;
  border: 1px solid var(--ab-ln);
  border-left: 2px solid var(--flame);
  background: var(--ink-2);
}

.page-about .ab-outscope p {
  margin: 10px 0 0;
  max-width: 68ch;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ab-body-soft);
}

/* ---------- 图片 ---------- */
.page-about .ab-figure {
  margin: 26px 0 0;
}

.page-about .ab-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--ab-ln);
  background: var(--ink-2);
  object-fit: cover;
}

.page-about .ab-figure figcaption {
  margin-top: 10px;
  font-size: 12px;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 流程 ---------- */
.page-about .ab-flow {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
}

.page-about .ab-flow__step {
  position: relative;
  margin-left: 5px;
  padding: 0 0 26px 22px;
  border-left: 1px solid var(--ab-ln);
}

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

.page-about .ab-flow__step::before {
  content: "";
  position: absolute;
  left: -4.5px;
  top: 7px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  border: 1px solid var(--cyan);
  background: var(--ink);
}

.page-about .ab-flow__step:last-child::before {
  background: var(--cyan);
}

.page-about .ab-flow__t {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--flame);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-flow__h {
  margin: 5px 0 7px;
  font-size: 17px;
  font-weight: 500;
  color: var(--bone);
}

.page-about .ab-flow__step p {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--ab-body-soft);
}

/* ---------- 赛季阶段 ---------- */
.page-about .ab-phase {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .ab-phase__item {
  padding: 18px 0;
  border-bottom: 1px solid var(--ab-ln-soft);
}

.page-about .ab-phase__item:first-child {
  border-top: 1px solid var(--ab-ln);
}

.page-about .ab-phase__item:last-child {
  border-bottom: 1px solid var(--ab-ln);
}

.page-about .ab-phase__no {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: var(--index-track);
  color: var(--paper);
}

.page-about .ab-phase__h {
  margin: 8px 0 6px;
  font-size: clamp(16px, 2vw, 19px);
  font-weight: 500;
  color: var(--bone);
}

.page-about .ab-phase__item p {
  margin: 0;
  max-width: 64ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--ab-body-soft);
}

/* ---------- 组织与分工 ---------- */
.page-about .ab-org {
  display: grid;
  gap: clamp(22px, 3vw, 36px);
}

.page-about .ab-org__main .ab-chapter__intro {
  margin-bottom: 4px;
}

.page-about .ab-groups {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
}

.page-about .ab-group {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: baseline;
  gap: 6px 16px;
  padding: 18px 0;
  border-bottom: 1px solid var(--ab-ln);
}

.page-about .ab-group:first-child {
  border-top: 1px solid var(--ab-ln);
}

.page-about .ab-group__name {
  font-size: 17px;
  font-weight: 500;
  color: var(--bone);
}

.page-about .ab-group__count {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 19px;
  color: var(--flame);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-group__desc {
  grid-column: 1 / -1;
  margin: 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--ab-body-soft);
}

/* ---------- 一致性与纠错 ---------- */
.page-about .ab-prose-grid {
  display: grid;
  gap: clamp(22px, 3vw, 36px);
}

.page-about .ab-side-panel {
  padding: 20px 18px;
  border: 1px solid var(--ab-ln);
  background: var(--ink-2);
}

.page-about .ab-rank {
  margin: 14px 0 0;
  padding: 0 0 0 20px;
  list-style: decimal;
}

.page-about .ab-rank li {
  padding: 7px 0;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--ab-body);
  border-bottom: 1px solid var(--ab-ln-soft);
}

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

.page-about .ab-side-panel__foot {
  margin: 14px 0 0;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 演进年表（靛紫区） ---------- */
.page-about .ab-era {
  position: relative;
  margin-top: clamp(24px, 4vw, 48px);
  padding: clamp(48px, 7vw, 100px) 0;
  background:
    radial-gradient(120% 88% at 10% 0%, rgba(42, 31, 82, .96) 0%, rgba(42, 31, 82, 0) 64%),
    linear-gradient(180deg, #1A143D 0%, var(--ink) 94%);
  border-top: 1px solid var(--ab-line-cyan);
  border-bottom: 1px solid var(--ab-ln);
}

.page-about .ab-era::before {
  content: "";
  position: absolute;
  left: -6%;
  right: -6%;
  top: 14px;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(63, 224, 200, .45), transparent);
  transform: rotate(-4deg);
  pointer-events: none;
}

.page-about .ab-era__head {
  max-width: 70ch;
}

.page-about .ab-chapter__no--era {
  display: block;
  font-size: 13px;
}

.page-about .ab-chapter__title--era {
  margin: 12px 0 16px;
}

.page-about .ab-era__lead {
  margin: 0;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.85;
  color: var(--ab-body);
}

.page-about .ab-figure--era {
  margin-top: clamp(26px, 4vw, 42px);
}

.page-about .ab-jump {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: clamp(26px, 4vw, 44px) 0 0;
}

.page-about .ab-jump__link {
  display: inline-block;
  padding: 7px 14px;
  border: 1px solid var(--ab-line-cyan);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--cyan-2);
  text-decoration: none;
  transition: background-color .2s var(--ease), color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .ab-jump__link:hover,
.page-about .ab-jump__link:focus-visible {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--ink);
}

.page-about .ab-timeline {
  list-style: none;
  margin: clamp(28px, 4vw, 46px) 0 0;
  padding: 0;
  display: grid;
  gap: clamp(22px, 3.4vw, 40px);
}

.page-about .ab-tl {
  display: grid;
  gap: 10px;
}

.page-about .ab-tl__year {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(24px, 3.4vw, 32px);
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--cyan);
  font-variant-numeric: tabular-nums slashed-zero;
}

.page-about .ab-tl--current .ab-tl__year {
  color: var(--flame);
}

.page-about .ab-tl__ver {
  display: inline-block;
  padding: 3px 9px;
  border: 1px solid var(--ab-ln);
  border-radius: var(--radius);
  font-size: 11px;
  letter-spacing: var(--index-track);
  color: var(--paper);
}

.page-about .ab-tl__h {
  margin: 12px 0 8px;
  font-size: clamp(17px, 2.2vw, 21px);
  font-weight: 500;
  color: var(--bone);
}

.page-about .ab-tl__body p {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.8;
  color: #B4C8C2;
}

/* ---------- 后续路径 ---------- */
.page-about .ab-next {
  padding: clamp(48px, 7vw, 92px) 0 clamp(40px, 6vw, 72px);
}

.page-about .ab-next__grid {
  display: grid;
  gap: 1px;
  margin-top: 20px;
  background: var(--ab-ln);
  border-top: 1px solid var(--ab-ln);
  border-bottom: 1px solid var(--ab-ln);
}

.page-about .ab-next__link {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 22px 18px;
  background: var(--ink);
  color: inherit;
  text-decoration: none;
  transition: background-color .22s var(--ease);
}

.page-about .ab-next__link:hover,
.page-about .ab-next__link:focus-visible {
  background: var(--ink-2);
}

.page-about .ab-next__k {
  font-size: 11px;
  letter-spacing: var(--index-track);
  color: var(--cyan);
}

.page-about .ab-next__t {
  font-size: 17px;
  font-weight: 500;
  color: var(--bone);
}

.page-about .ab-next__d {
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--mist);
}

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .ab-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 900px) {
  .page-about .ab-hero__grid {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    column-gap: clamp(20px, 3vw, 40px);
  }

  .page-about .ab-hero__kicker {
    grid-column: 1 / -1;
  }

  .page-about .ab-hero__title {
    grid-column: 1 / span 9;
  }

  .page-about .ab-hero__lead {
    grid-column: 5 / -1;
  }

  .page-about .ab-hero__facts {
    grid-column: 1 / -1;
  }

  .page-about .ab-chapter__inner {
    grid-template-columns: 132px minmax(0, 1fr);
    column-gap: clamp(24px, 4vw, 56px);
  }

  .page-about .ab-chapter__side {
    display: block;
    border-right: 1px solid var(--ab-ln);
    padding-right: 22px;
  }

  .page-about .ab-chapter__side::after {
    display: none;
  }

  .page-about .ab-chapter__no {
    display: block;
    font-size: 32px;
    line-height: 1;
    letter-spacing: .02em;
  }

  .page-about .ab-dim__body {
    padding-left: 38px;
  }

  .page-about .ab-org {
    grid-template-columns: minmax(0, 1fr) 280px;
    align-items: start;
  }

  .page-about .ab-figure--tall {
    margin-top: 4px;
  }

  .page-about .ab-prose-grid {
    grid-template-columns: minmax(0, 1fr) 268px;
    align-items: start;
  }

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

@media (min-width: 1080px) {
  .page-about .ab-chapter--narrow .ab-chapter__body {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 210px;
    column-gap: clamp(26px, 4vw, 56px);
  }

  .page-about .ab-chapter--narrow .ab-chapter__body > * {
    grid-column: 1;
  }

  .page-about .ab-chapter--narrow .ab-chapter__note {
    grid-column: 2;
    grid-row: 1 / span 12;
    margin-top: 6px;
    padding-left: 18px;
    max-width: none;
  }

  .page-about .ab-tl {
    grid-template-columns: 148px minmax(0, 1fr);
    column-gap: clamp(20px, 3vw, 44px);
    gap: 0;
  }

  .page-about .ab-tl__year {
    border-right: 1px solid var(--ab-line-cyan);
    padding-right: 18px;
  }

  .page-about .ab-tl__body {
    padding: 0 0 clamp(24px, 3vw, 38px) 22px;
    border-left: 1px solid transparent;
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-dim__sum,
  .page-about .ab-jump__link,
  .page-about .ab-next__link {
    transition: none;
  }
}