.page-about {
  --ab-max: 1180px;
  --ab-pad: clamp(18px, 5vw, 44px);
  color: var(--paper);
}

.page-about .ab-wrap {
  width: 100%;
  max-width: var(--ab-max);
  margin: 0 auto;
  padding-inline: var(--ab-pad);
}

.page-about .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

/* ---------- 首屏 ---------- */

.page-about .ab-hero {
  position: relative;
  display: grid;
  gap: 32px;
  padding: clamp(26px, 5vw, 62px) var(--ab-pad) clamp(38px, 6vw, 78px);
  max-width: 1420px;
  overflow: hidden;
  isolation: isolate;
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: -30% -10% auto -10%;
  height: 78%;
  background:
    radial-gradient(58% 58% at 78% 18%, rgba(255, 91, 26, 0.22), transparent 70%),
    radial-gradient(52% 52% at 8% 42%, rgba(47, 211, 200, 0.1), transparent 72%);
  pointer-events: none;
  z-index: 0;
}

.page-about .ab-hero__copy,
.page-about .ab-hero__media {
  position: relative;
  z-index: 1;
}

.page-about .ab-hero h1 {
  margin: 16px 0 0;
  font-size: clamp(2.3rem, 8.4vw, 5.4rem);
  line-height: 0.98;
  letter-spacing: -0.035em;
  font-weight: 900;
  color: var(--paper);
  max-width: 16ch;
}

.page-about .ab-hero__lede {
  margin: 22px 0 0;
  max-width: 58ch;
  font-size: clamp(0.98rem, 1.6vw, 1.125rem);
  line-height: 1.8;
  color: var(--muted);
}

.page-about .ab-hero__years {
  list-style: none;
  margin: 32px 0 0;
  padding: 22px 0 0;
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px 16px;
}

.page-about .ab-hero__years li {
  position: relative;
  padding-top: 14px;
}

.page-about .ab-hero__years li::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 26px;
  height: 3px;
  background: var(--ember);
}

.page-about .ab-year {
  display: block;
  font-size: clamp(1.4rem, 4.2vw, 2rem);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .ab-year__cap {
  display: block;
  margin-top: 9px;
  font-size: 0.78rem;
  letter-spacing: 0.05em;
  color: var(--muted);
}

.page-about .ab-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.page-about .ab-hero__media {
  margin: 0;
  border: 1px solid var(--line);
  background: var(--ink-2);
  clip-path: polygon(0 0, 100% 0, 100% 100%, 0 93%);
}

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

.page-about .ab-hero__media img {
  aspect-ratio: 16 / 10;
}

.page-about .media__cap {
  display: block;
  padding: 12px 16px;
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  color: var(--muted);
  border-top: 1px solid var(--line);
  background: rgba(14, 15, 18, 0.72);
}

/* ---------- 章节通用 ---------- */

.page-about .ab-scope,
.page-about .ab-cadence,
.page-about .ab-benefits,
.page-about .ab-history,
.page-about .ab-next {
  padding-block: clamp(46px, 7vw, 88px);
  border-top: 1px solid var(--line);
}

.page-about .ab-cadence {
  background: var(--ink-2);
}

.page-about .ab-history {
  background: var(--ink-2);
}

.page-about .ab-head {
  margin-bottom: clamp(26px, 4vw, 44px);
}

.page-about .ab-head h2 {
  margin: 12px 0 0;
  font-size: clamp(1.7rem, 5vw, 2.9rem);
  line-height: 1.1;
  letter-spacing: -0.025em;
  font-weight: 900;
  color: var(--paper);
}

.page-about .ab-head__lede {
  margin: 16px 0 0;
  max-width: 60ch;
  color: var(--muted);
  line-height: 1.8;
}

/* ---------- 覆盖范围 ---------- */

.page-about .ab-scope__grid {
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-scope__item {
  background: var(--ink);
  padding: clamp(22px, 3vw, 32px);
}

.page-about .ab-scope__item--accent {
  background: var(--ink-2);
}

.page-about .ab-scope__idx {
  display: block;
  font-size: 1.05rem;
  letter-spacing: 0.08em;
  color: var(--ember);
}

.page-about .ab-scope__item h3 {
  margin: 14px 0 0;
  font-size: clamp(1.12rem, 2.4vw, 1.35rem);
  font-weight: 800;
  color: var(--paper);
  letter-spacing: -0.01em;
}

.page-about .ab-scope__item p {
  margin: 12px 0 0;
  color: var(--muted);
  line-height: 1.8;
  font-size: 0.95rem;
}

.page-about .ab-stats {
  list-style: none;
  margin: clamp(26px, 4vw, 42px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-stats .stat {
  background: var(--ink-2);
  padding: 20px 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.page-about .ab-stats .stat__value {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 4.6vw, 2.3rem);
  line-height: 1;
  color: var(--ember);
  letter-spacing: -0.02em;
}

.page-about .ab-stats .stat__label {
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  color: var(--muted);
}

/* ---------- 更新纪律 ---------- */

.page-about .ab-cadence__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 2px solid var(--ember-deep);
  padding-left: clamp(18px, 3vw, 30px);
  display: grid;
  gap: clamp(24px, 3.6vw, 38px);
}

.page-about .ab-cadence__item {
  position: relative;
}

.page-about .ab-cadence__item::before {
  content: "";
  position: absolute;
  left: calc(-1 * clamp(18px, 3vw, 30px) - 7px);
  top: 8px;
  width: 12px;
  height: 12px;
  background: var(--ember);
  border-radius: 50%;
}

.page-about .ab-cadence__time {
  display: block;
  font-size: clamp(1rem, 2.4vw, 1.24rem);
  color: var(--lime);
  letter-spacing: -0.01em;
}

.page-about .ab-cadence__body h3 {
  margin: 10px 0 0;
  font-size: clamp(1.08rem, 2.3vw, 1.3rem);
  font-weight: 800;
  color: var(--paper);
}

.page-about .ab-cadence__body p {
  margin: 10px 0 0;
  max-width: 62ch;
  color: var(--muted);
  line-height: 1.8;
  font-size: 0.95rem;
}

.page-about .ab-cadence__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 14px !important;
}

/* ---------- 会员权益 ---------- */

.page-about .ab-benefits__chips {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 0 0 26px;
}

.page-about .ab-benefit {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--ink-2);
  overflow: hidden;
}

.page-about .ab-benefit + .ab-benefit {
  margin-top: 14px;
}

.page-about .ab-benefit__sum {
  list-style: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 18px clamp(16px, 2.6vw, 24px);
  border-left: 3px solid var(--ember);
  transition: background-color 0.18s ease;
}

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

.page-about .ab-benefit__sum::marker {
  content: "";
}

.page-about .ab-benefit__sum:hover {
  background: var(--card);
}

.page-about .ab-benefit__sum::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 1.3rem;
  line-height: 1;
  color: var(--ember);
}

.page-about .ab-benefit[open] .ab-benefit__sum::after {
  content: "\2212";
}

.page-about .ab-benefit__name {
  font-size: clamp(1.02rem, 2.3vw, 1.22rem);
  font-weight: 800;
  color: var(--paper);
  letter-spacing: -0.01em;
}

.page-about .ab-benefit__body {
  padding: 4px clamp(16px, 2.6vw, 24px) 24px;
  border-top: 1px solid var(--line);
}

.page-about .ab-benefit__body > p {
  margin: 16px 0 0;
  color: var(--muted);
  line-height: 1.8;
  font-size: 0.95rem;
  max-width: 62ch;
}

.page-about .ab-benefit__list {
  margin: 14px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 12px;
}

.page-about .ab-benefit__list li {
  position: relative;
  padding-left: 20px;
  color: var(--muted);
  line-height: 1.78;
  font-size: 0.95rem;
}

.page-about .ab-benefit__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 9px;
  height: 2px;
  background: var(--cyan);
}

.page-about .ab-benefit__list strong {
  color: var(--paper);
  font-weight: 700;
}

/* ---------- 版本演进 ---------- */

.page-about .ab-history__grid {
  display: grid;
  gap: clamp(26px, 4vw, 44px);
}

.page-about .ab-history__list.timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 2px solid var(--line);
  padding-left: clamp(18px, 3vw, 28px);
  display: grid;
  gap: clamp(24px, 3.4vw, 34px);
}

.page-about .ab-history__item {
  position: relative;
}

.page-about .ab-history__item::before {
  content: "";
  position: absolute;
  left: calc(-1 * clamp(18px, 3vw, 28px) - 6px);
  top: 10px;
  width: 10px;
  height: 10px;
  background: var(--ember);
}

.page-about .ab-history__year {
  display: block;
  font-size: clamp(1.6rem, 5vw, 2.4rem);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--ember);
}

.page-about .ab-history__text h3 {
  margin: 10px 0 0;
  font-size: clamp(1.06rem, 2.3vw, 1.26rem);
  font-weight: 800;
  color: var(--paper);
}

.page-about .ab-history__text p {
  margin: 10px 0 0;
  max-width: 56ch;
  color: var(--muted);
  line-height: 1.8;
  font-size: 0.95rem;
}

.page-about .ab-history__media {
  margin: 0;
  border: 1px solid var(--line);
  background: var(--ink);
  align-self: start;
}

.page-about .ab-history__media img {
  aspect-ratio: 3 / 4;
}

/* ---------- 看台文化 ---------- */

.page-about .ab-stands {
  padding-block: clamp(52px, 8vw, 104px);
  border-top: 1px solid var(--line);
  background:
    linear-gradient(180deg, rgba(255, 91, 26, 0.08), transparent 40%),
    var(--ink);
}

.page-about .ab-stands__inner {
  width: 100%;
  max-width: var(--ab-max);
  margin: 0 auto;
  padding-inline: var(--ab-pad);
}

.page-about .ab-stands h2 {
  margin: 14px 0 0;
  font-size: clamp(1.9rem, 6vw, 3.4rem);
  line-height: 1.06;
  letter-spacing: -0.03em;
  font-weight: 900;
  color: var(--paper);
  max-width: 18ch;
}

.page-about .ab-stands__lede {
  margin: 20px 0 0;
  max-width: 58ch;
  color: var(--muted);
  line-height: 1.85;
  font-size: clamp(0.98rem, 1.6vw, 1.08rem);
}

.page-about .ab-stands__grid {
  display: grid;
  gap: clamp(24px, 4vw, 40px);
  margin-top: clamp(26px, 4vw, 44px);
}

.page-about .ab-stands__notes p {
  margin: 0 0 16px;
  max-width: 58ch;
  color: var(--muted);
  line-height: 1.85;
  font-size: 0.96rem;
}

.page-about .ab-stands__chips {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 22px !important;
}

.page-about .ab-stands__media {
  margin: 0;
  border: 1px solid var(--line);
  background: var(--ink-2);
}

.page-about .ab-stands__media img {
  aspect-ratio: 3 / 2;
}

/* ---------- 下一步 ---------- */

.page-about .ab-next__grid {
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-next__link {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: clamp(20px, 3vw, 28px);
  background: var(--ink);
  text-decoration: none;
  transition: background-color 0.18s ease, transform 0.18s ease;
}

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

.page-about .ab-next__label {
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--ember);
  letter-spacing: -0.01em;
}

.page-about .ab-next__desc {
  font-size: 0.9rem;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------- 响应式 ---------- */

@media (min-width: 720px) {
  .page-about .ab-hero__years {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

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

@media (min-width: 940px) {
  .page-about .ab-hero {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    align-items: end;
  }

  .page-about .ab-hero__media {
    margin-bottom: 12px;
  }

  .page-about .ab-history__grid {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 0.7fr);
    align-items: start;
  }

  .page-about .ab-stands__grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: center;
  }

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

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