.page-about {
  position: relative;
  padding-bottom: var(--section-gap);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .ab-open {
  padding: clamp(24px, 5vw, 56px) 0 clamp(40px, 6vw, 72px);
}
.page-about .ab-open__grid {
  display: grid;
  gap: clamp(28px, 4vw, 56px);
}
.page-about .ab-open__lead {
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.page-about .ab-open__lead .xg-lede {
  max-width: 46ch;
}
.page-about .ab-facts {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(160deg, rgba(36, 19, 68, .95), rgba(20, 10, 43, .85));
  padding: 22px;
  box-shadow: var(--shadow-deep);
}
.page-about .ab-facts dl {
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 16px;
}
.page-about .ab-fact dt {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--text-dim);
}
.page-about .ab-fact dd {
  margin: 6px 0 0;
  font-size: 1.05rem;
  color: var(--text);
}
@media (min-width: 900px) {
  .page-about .ab-open__grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(280px, 1fr);
    align-items: end;
    gap: clamp(40px, 5vw, 80px);
  }
  .page-about .ab-facts dl {
    grid-template-columns: minmax(0, 1fr);
    gap: 20px;
  }
}

/* ---------- 时间轴 ---------- */
.page-about .ab-timeline {
  position: relative;
  margin-top: clamp(40px, 6vw, 88px);
}
.page-about .ab-timeline__bg {
  position: absolute;
  inset: 0;
  margin: 0;
  opacity: .18;
  pointer-events: none;
  z-index: 0;
  -webkit-mask-image: linear-gradient(180deg, transparent, #000 22%, #000 72%, transparent);
  mask-image: linear-gradient(180deg, transparent, #000 22%, #000 72%, transparent);
}
.page-about .ab-timeline__bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.page-about .ab-timeline .xg-wrap {
  position: relative;
  z-index: 1;
}

.page-about .ab-sec-head {
  max-width: 62ch;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.page-about .ab-sec-head__lead {
  margin: 0;
  color: var(--text-dim);
  font-size: 1rem;
  line-height: 1.85;
}

.page-about .ab-timeline__body {
  display: grid;
  gap: 28px;
  margin-top: clamp(32px, 5vw, 56px);
}
.page-about .ab-timeline__rail {
  display: flex;
  gap: 10px;
  overflow-x: auto;
  padding-bottom: 6px;
  scrollbar-width: none;
}
.page-about .ab-timeline__rail::-webkit-scrollbar {
  display: none;
}
.page-about .ab-year {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--text-dim);
  text-decoration: none;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 6px 12px;
  transition: color .2s var(--ease), border-color .2s var(--ease), background-color .2s var(--ease);
}
.page-about .ab-year:hover,
.page-about .ab-year:focus-visible {
  color: var(--ink-950);
  background: var(--lime);
  border-color: var(--lime);
  outline: none;
}
@media (min-width: 1000px) {
  .page-about .ab-timeline__body {
    grid-template-columns: 92px minmax(0, 1fr);
    gap: clamp(32px, 5vw, 72px);
  }
  .page-about .ab-timeline__rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
    overflow: visible;
    position: sticky;
    top: 132px;
    align-self: start;
  }
}

.page-about .ab-track {
  --ab-indent: 24px;
  list-style: none;
  margin: 0;
  padding: 0 0 0 var(--ab-indent);
  border-left: 1px solid var(--line);
  display: grid;
  gap: clamp(40px, 5vw, 72px);
}
.page-about .ab-stage {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.page-about .ab-stage::before {
  content: "";
  position: absolute;
  top: 6px;
  left: calc(-1 * var(--ab-indent) - 7px);
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--lime);
  box-shadow: 0 0 0 5px rgba(184, 255, 63, .12);
}
.page-about .ab-stage__no {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--lime);
}
.page-about .ab-stage .xg-h3 {
  margin: 0;
}
.page-about .ab-stage > p {
  margin: 0;
  color: var(--text-dim);
}
.page-about .ab-stage p.ab-stage__gain {
  color: var(--text);
  border-left: 2px solid var(--amber);
  padding-left: 12px;
  font-size: .95rem;
}

/* ---------- 纸层：版本节奏 ---------- */
.page-about .ab-rhythm {
  margin: clamp(56px, 7vw, 104px) 0;
  padding: clamp(36px, 5vw, 64px) 0;
  border-top: 1px solid var(--paper-line);
  border-bottom: 1px solid var(--paper-line);
}
.page-about .ab-rhythm__inner {
  display: grid;
  gap: clamp(28px, 4vw, 48px);
}
.page-about .ab-rhythm .xg-h2,
.page-about .ab-rhythm .xg-h3 {
  color: var(--text-on-paper);
}
.page-about .ab-rhythm .xg-eyebrow,
.page-about .ab-rhythm .ab-sec-head__lead {
  color: var(--text-dim-on-paper);
}
.page-about .ab-rules {
  counter-reset: abrule;
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 18px;
}
.page-about .ab-rule {
  counter-increment: abrule;
  border-top: 1px solid var(--paper-line);
  padding-top: 16px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.page-about .ab-rule::before {
  content: "0" counter(abrule);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--text-dim-on-paper);
}
.page-about .ab-rule p {
  margin: 0;
  color: var(--text-dim-on-paper);
}
@media (min-width: 900px) {
  .page-about .ab-rhythm__inner {
    grid-template-columns: minmax(0, .9fr) minmax(0, 1.2fr);
    gap: clamp(32px, 5vw, 72px);
    align-items: start;
  }
}

/* ---------- 团队 ---------- */
.page-about .ab-team {
  margin-top: clamp(56px, 7vw, 104px);
}
.page-about .ab-team__grid {
  display: grid;
  gap: clamp(32px, 5vw, 64px);
}
.page-about .ab-team__text {
  display: flex;
  flex-direction: column;
  gap: 14px;
}
.page-about .ab-team__figure {
  margin: 0;
}
.page-about .ab-split {
  display: flex;
  gap: 3px;
  height: 14px;
  margin: 16px 0 6px;
}
.page-about .ab-split__seg {
  display: block;
  border-radius: 4px;
  min-width: 4px;
}
.page-about .ab-split__seg--dev {
  background: var(--lime);
}
.page-about .ab-split__seg--cs {
  background: var(--amber);
}
.page-about .ab-split__seg--ops {
  background: var(--line);
}
.page-about .ab-roles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}
.page-about .ab-role {
  border: 1px solid transparent;
  border-radius: 12px;
  padding: 12px 14px;
  transition: border-color .2s var(--ease), background-color .2s var(--ease);
}
.page-about .ab-role:hover {
  border-color: var(--line);
  background: rgba(36, 19, 68, .55);
}
.page-about .ab-role__head {
  margin: 0;
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text);
  font-weight: 600;
}
.page-about .ab-role__desc {
  margin: 6px 0 0;
  color: var(--text-dim);
  font-size: .95rem;
}
.page-about .ab-role__dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex: 0 0 auto;
}
.page-about .ab-role__dot--dev {
  background: var(--lime);
}
.page-about .ab-role__dot--cs {
  background: var(--amber);
}
.page-about .ab-role__dot--ops {
  background: var(--line);
}
@media (min-width: 900px) {
  .page-about .ab-team__grid {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
    align-items: center;
  }
}

/* ---------- 资质 ---------- */
.page-about .ab-creds {
  margin-top: clamp(56px, 7vw, 104px);
}
.page-about .ab-creds .xg-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: clamp(22px, 3.5vw, 40px);
}
.page-about .ab-creds__figure {
  width: min(220px, 58vw);
  margin: 0;
}
.page-about .ab-sec-head--center {
  align-items: center;
  text-align: center;
}
.page-about .ab-badges {
  list-style: none;
  margin: 0;
  padding: 0;
  width: 100%;
  display: grid;
  gap: 14px;
}
.page-about .ab-badge {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  background: linear-gradient(165deg, rgba(36, 19, 68, .92), rgba(20, 10, 43, .8));
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: border-color .22s var(--ease), transform .22s var(--ease);
}
.page-about .ab-badge:hover,
.page-about .ab-badge:focus-visible,
.page-about .ab-badge:focus-within {
  border-color: var(--lime);
  transform: translateY(-2px);
  outline: none;
}
.page-about .ab-badge .xg-tag {
  align-self: flex-start;
}
.page-about .ab-badge .xg-h3 {
  margin: 0;
  font-size: 1.05rem;
}
.page-about .ab-badge__note {
  margin: 0;
  color: var(--text-dim);
  font-size: .95rem;
  line-height: 1.75;
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height .32s var(--ease), opacity .32s var(--ease);
}
.page-about .ab-badge:hover .ab-badge__note,
.page-about .ab-badge:focus-within .ab-badge__note,
.page-about .ab-badge:focus-visible .ab-badge__note {
  max-height: 160px;
  opacity: 1;
}
@media (min-width: 720px) {
  .page-about .ab-badges {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}
@media (hover: none) {
  .page-about .ab-badge__note {
    max-height: none;
    opacity: 1;
  }
}

/* ---------- 合作与监测 ---------- */
.page-about .ab-eco {
  margin-top: clamp(56px, 7vw, 104px);
}
.page-about .ab-eco__grid {
  display: grid;
  gap: clamp(18px, 3vw, 32px);
  margin-top: clamp(28px, 4vw, 48px);
}
.page-about .ab-eco__part {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: clamp(20px, 3vw, 30px);
  background: rgba(20, 10, 43, .7);
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.page-about .ab-eco__part .xg-h3 {
  margin: 0;
}
.page-about .ab-eco__part p {
  margin: 0;
  color: var(--text-dim);
}
.page-about .ab-eco__tags {
  list-style: none;
  margin: 4px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.page-about .ab-regions {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
  margin-top: 4px;
}
.page-about .ab-region {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  text-align: center;
  padding: 10px 6px;
  border: 1px dashed var(--line);
  border-radius: 10px;
  color: var(--text-dim);
}
@media (min-width: 860px) {
  .page-about .ab-eco__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

/* ---------- 收束 ---------- */
.page-about .ab-close {
  margin-top: clamp(64px, 9vw, 128px);
  padding: clamp(48px, 7vw, 96px) 0 clamp(24px, 4vw, 48px);
  border-top: 1px solid var(--line);
}
.page-about .ab-close__inner {
  display: flex;
  flex-direction: column;
  gap: 18px;
}
.page-about .ab-close .xg-h2 {
  max-width: 20ch;
}
.page-about .ab-close__list {
  list-style: none;
  margin: clamp(20px, 3vw, 36px) 0 0;
  padding: 0;
  display: grid;
  gap: clamp(20px, 3vw, 34px);
}
.page-about .ab-close__list li {
  display: flex;
  align-items: flex-start;
  gap: 18px;
}
.page-about .ab-close__no {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--lime);
  padding-top: .55em;
  flex: 0 0 auto;
}
.page-about .ab-close__list p {
  margin: 0;
  font-size: clamp(1.05rem, 2vw, 1.4rem);
  line-height: 1.6;
  color: var(--text);
}
.page-about .ab-next {
  margin-top: clamp(32px, 5vw, 56px);
  display: flex;
  flex-direction: column;
  gap: 12px;
  max-width: 70ch;
}
.page-about .ab-next p {
  margin: 0;
  color: var(--text-dim);
}
.page-about .ab-next a {
  color: var(--lime);
  text-decoration: none;
  border-bottom: 1px solid rgba(184, 255, 63, .4);
  transition: border-color .2s var(--ease);
}
.page-about .ab-next a:hover,
.page-about .ab-next a:focus-visible {
  border-bottom-color: var(--lime);
  outline: none;
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-year,
  .page-about .ab-role,
  .page-about .ab-badge,
  .page-about .ab-badge__note,
  .page-about .ab-next a {
    transition: none;
  }
  .page-about .ab-badge:hover,
  .page-about .ab-badge:focus-within {
    transform: none;
  }
}
</main>