.page-about {
  --ab-pad: clamp(52px, 6.5vw, 92px);
  --ab-soft: rgba(27, 26, 23, 0.66);
  --ab-rail-w: 200px;
}

/* ---------------- 首屏 ---------------- */
.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(20px, 3vw, 34px) 0 clamp(48px, 6vw, 84px);
  background:
    radial-gradient(115% 88% at 6% 0%, rgba(240, 178, 122, 0.26) 0%, rgba(245, 239, 230, 0) 60%),
    linear-gradient(178deg, var(--cream) 0%, var(--cream-2) 72%, rgba(237, 228, 214, 0.35) 100%);
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 72px 72px;
  pointer-events: none;
}

.page-about .ab-hero .wrap {
  position: relative;
  z-index: 1;
}

.page-about .ab-hero__crumbs {
  margin-bottom: clamp(22px, 3vw, 38px);
}

.page-about .ab-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(30px, 4vw, 52px);
  align-items: start;
}

@media (min-width: 980px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.12fr);
    gap: clamp(36px, 4.5vw, 68px);
  }
}

.page-about .ab-hero__kicker {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.16em;
  color: var(--soil);
}

.page-about .ab-hero__title {
  margin: 0 0 clamp(18px, 2.2vw, 26px);
  line-height: 1.08;
  letter-spacing: -0.022em;
  color: var(--ink);
}

.page-about .ab-hero__title::after {
  content: "";
  display: block;
  width: 76px;
  height: 4px;
  margin-top: 22px;
  background: var(--soil);
  transform: skewX(-26deg);
}

.page-about .ab-hero__lead {
  max-width: 40ch;
  margin: 0 0 clamp(24px, 3vw, 38px);
  font-size: clamp(1rem, 1.05vw, 1.125rem);
  line-height: 1.8;
  color: var(--ink);
}

.page-about .ab-hero__facts {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  padding: 0;
  background: var(--hair);
  border: 1px solid var(--hair);
}

.page-about .ab-hero__facts li {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 18px 14px;
  background: var(--cream);
}

.page-about .ab-hero__num {
  display: block;
  font-size: clamp(1.35rem, 2.4vw, 1.85rem);
  font-weight: 700;
  line-height: 1;
  color: var(--pine);
}

.page-about .ab-hero__num em {
  font-style: normal;
  font-size: 0.7em;
  color: var(--soil);
  margin-left: 2px;
}

.page-about .ab-hero__fact {
  font-size: 0.8125rem;
  line-height: 1.5;
  color: var(--ab-soft);
}

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

.page-about .ab-hero__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 2 / 1;
  object-fit: cover;
}

/* ---------------- 通用章节 ---------------- */
.page-about .ab-sec {
  padding: var(--ab-pad) 0;
}

.page-about .ab-sec--pine {
  background: var(--pine);
  color: var(--cream);
}

.page-about .ab-sec--dark {
  background: var(--dusk);
  color: var(--cream);
}

.page-about .ab-sec--archive {
  background: var(--cream-2);
  border-top: 1px solid var(--hair);
  border-bottom: 1px solid var(--hair);
}

.page-about .ab-head {
  margin-bottom: clamp(30px, 4vw, 52px);
}

.page-about .ab-sec--pine .ab-head,
.page-about .ab-sec--dark .ab-head {
  color: var(--cream);
}

.page-about .ab-sec--pine .sec-head__note,
.page-about .ab-sec--dark .sec-head__note {
  color: rgba(245, 239, 230, 0.72);
}

/* ---------------- 四格非对称图解 ---------------- */
.page-about .ab-quad {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--hair);
  border: 1px solid var(--hair);
}

.page-about .ab-quad__item {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: clamp(22px, 2.6vw, 34px);
  background: var(--cream);
  border-left: 4px solid transparent;
  transition: background var(--dur) ease, border-color var(--dur) ease;
}

.page-about .ab-quad__item--a {
  border-left-color: var(--soil);
}
.page-about .ab-quad__item--b {
  border-left-color: var(--brass);
}
.page-about .ab-quad__item--c {
  border-left-color: var(--pine);
}
.page-about .ab-quad__item--d {
  border-left-color: var(--field);
}

.page-about .ab-quad__item:hover,
.page-about .ab-quad__item:focus-within {
  background: #fff;
}

.page-about .ab-quad__code {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--ink);
  background: var(--amber);
  border-radius: var(--radius);
}

.page-about .ab-quad__name {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--ink);
}

.page-about .ab-quad__desc {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--ink);
  max-width: 42ch;
}

.page-about .ab-quad__more {
  margin: 0;
  padding-top: 12px;
  border-top: 1px solid var(--hair-soft);
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--ab-soft);
}

@media (min-width: 840px) {
  .page-about .ab-quad {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    grid-template-rows: auto auto auto;
  }
  .page-about .ab-quad__item--a {
    grid-column: 1 / span 7;
    grid-row: 1 / span 2;
    min-height: 300px;
  }
  .page-about .ab-quad__item--b {
    grid-column: 8 / span 5;
    grid-row: 1;
  }
  .page-about .ab-quad__item--c {
    grid-column: 8 / span 5;
    grid-row: 2;
  }
  .page-about .ab-quad__item--d {
    grid-column: 5 / span 8;
    grid-row: 3;
  }
}

/* ---------------- 版本时间轴 ---------------- */
.page-about .ab-versions {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 3.4vw, 46px);
}

@media (min-width: 900px) {
  .page-about .ab-versions {
    grid-template-columns: var(--ab-rail-w) minmax(0, 1fr);
    gap: clamp(34px, 4.5vw, 68px);
  }
  .page-about .ab-rail {
    position: sticky;
    top: 128px;
    align-self: start;
  }
}

.page-about .ab-rail__title {
  margin: 0 0 18px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--brass);
}

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

.page-about .ab-rail__list::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 10px;
  bottom: 10px;
  width: 1px;
  background: var(--hair-dark);
}

.page-about .ab-rail__item {
  position: relative;
  margin-bottom: 22px;
}

.page-about .ab-rail__item:last-child {
  margin-bottom: 0;
}

.page-about .ab-rail__item::before {
  content: "";
  position: absolute;
  left: -22px;
  top: 7px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--brass);
  box-shadow: 0 0 0 3px var(--pine);
}

.page-about .ab-rail__item a {
  display: flex;
  flex-direction: column;
  gap: 4px;
  text-decoration: none;
  color: rgba(245, 239, 230, 0.66);
  transition: color var(--dur) ease;
}

.page-about .ab-rail__item a .mono {
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--amber);
}

.page-about .ab-rail__item a span:last-child {
  font-size: 0.8125rem;
  line-height: 1.5;
}

.page-about .ab-rail__item a:hover,
.page-about .ab-rail__item a:focus-visible {
  color: var(--cream);
}

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

.page-about .ab-vblock {
  padding: clamp(18px, 2.2vw, 28px) 0;
  border-top: 1px solid var(--hair-dark);
  scroll-margin-top: 150px;
}

.page-about .ab-vblock__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin-bottom: 10px;
}

.page-about .ab-vblock__tag {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 46px;
  padding: 5px 10px;
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--ink);
  background: var(--amber);
  border-radius: var(--radius);
}

.page-about .ab-vblock__title {
  margin: 0;
  color: var(--cream);
  font-family: var(--font-sans);
  font-weight: 800;
}

.page-about .ab-vblock__text {
  margin: 0;
  max-width: 46ch;
  font-size: 0.9375rem;
  line-height: 1.82;
  color: rgba(245, 239, 230, 0.78);
}

.page-about .ab-versions__figure {
  margin: clamp(30px, 3.6vw, 48px) 0 0;
}

.page-about .ab-sec--pine .figure__cap {
  color: rgba(245, 239, 230, 0.66);
}

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

/* ---------------- 团队 ---------------- */
.page-about .ab-team {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-team__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  padding: clamp(22px, 2.6vw, 32px) 0;
  border-top: 1px solid var(--hair-dark);
}

.page-about .ab-team__item:last-child {
  border-bottom: 1px solid var(--hair-dark);
}

@media (min-width: 720px) {
  .page-about .ab-team__item {
    grid-template-columns: 220px minmax(0, 1fr);
    gap: 32px;
    align-items: start;
  }
}

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

.page-about .ab-team__idx {
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--brass);
}

.page-about .ab-team__name {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--cream);
}

.page-about .ab-team__text {
  margin: 0;
  max-width: 48ch;
  font-size: 0.9375rem;
  line-height: 1.82;
  color: rgba(245, 239, 230, 0.76);
}

/* ---------------- 比赛日刻度带 ---------------- */
.page-about .ab-scrollx {
  overflow-x: auto;
  padding-bottom: 14px;
  -webkit-overflow-scrolling: touch;
}

.page-about .ab-scrollx .ab-timeline {
  min-width: 780px;
  padding-top: 22px;
  border-top: 2px solid var(--hair);
}

.page-about .ab-timeline .tl-node {
  border-top: none;
  padding-top: 18px;
}

.page-about .ab-timeline .tl-node::before {
  background: var(--brass);
  box-shadow: 0 0 0 3px var(--cream);
}

.page-about .ab-timeline .tl-node__time {
  color: var(--pine);
  font-weight: 700;
  font-size: 0.8125rem;
}

.page-about .ab-timeline .tl-node__label {
  color: var(--ink);
  font-weight: 700;
}

.page-about .ab-timeline .tl-node__desc {
  color: var(--ab-soft);
  font-size: 0.8125rem;
  line-height: 1.7;
}

/* ---------------- 比较基准 ---------------- */
.page-about .ab-base {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 3vw, 48px);
}

@media (min-width: 860px) {
  .page-about .ab-base {
    grid-template-columns: minmax(0, 4fr) minmax(0, 7fr);
    gap: clamp(34px, 4.5vw, 72px);
  }
}

.page-about .ab-base__side {
  border-left: 4px solid var(--soil);
  padding-left: clamp(16px, 2vw, 24px);
}

.page-about .ab-base__mark {
  margin: 0 0 12px;
  font-size: 0.8125rem;
  letter-spacing: 0.18em;
  color: var(--soil);
}

.page-about .ab-base__title {
  margin: 0;
  color: var(--ink);
  font-family: var(--font-sans);
  font-weight: 800;
  line-height: 1.24;
}

.page-about .ab-base__body p {
  margin: 0 0 18px;
  max-width: 46ch;
  font-size: 0.9375rem;
  line-height: 1.85;
  color: var(--ink);
}

.page-about .ab-base__body p:last-of-type {
  margin-bottom: 0;
}

.page-about .ab-fold {
  margin-top: 24px;
}

/* ---------------- 协作网络 ---------------- */
.page-about .ab-coop {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 3.6vw, 54px);
  align-items: start;
}

@media (min-width: 900px) {
  .page-about .ab-coop {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  }
}

.page-about .ab-coop__text p {
  margin: 0 0 18px;
  max-width: 46ch;
  font-size: 0.9375rem;
  line-height: 1.85;
  color: var(--ink);
}

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

.page-about .ab-coop__figure img {
  aspect-ratio: 1 / 1;
}

/* ---------------- 红土斜切收束 ---------------- */
.page-about .ab-outro {
  margin-top: clamp(40px, 5vw, 76px);
  padding: clamp(70px, 8vw, 104px) 0 clamp(62px, 7vw, 92px);
  background: var(--soil);
  color: var(--cream);
  clip-path: polygon(0 0, 100% 26px, 100% 100%, 0 calc(100% - 26px));
}

.page-about .ab-outro__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 3vw, 44px);
  align-items: center;
}

@media (min-width: 860px) {
  .page-about .ab-outro__inner {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 0.85fr);
    gap: clamp(34px, 4vw, 64px);
  }
}

.page-about .ab-outro__title {
  margin: 0 0 14px;
  color: var(--cream);
  font-family: var(--font-sans);
  font-weight: 800;
  line-height: 1.2;
}

.page-about .ab-outro__text p {
  margin: 0;
  max-width: 46ch;
  font-size: 0.9375rem;
  line-height: 1.82;
  color: rgba(245, 239, 230, 0.86);
}

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

.page-about .ab-outro__btn,
.page-about .ab-outro__btn2 {
  text-decoration: none;
}

.page-about .ab-outro__btn2 {
  color: var(--cream);
  border-color: rgba(245, 239, 230, 0.5);
}

.page-about .ab-outro__btn2:hover,
.page-about .ab-outro__btn2:focus-visible {
  color: var(--dusk);
  background: var(--cream);
  border-color: var(--cream);
}

/* ---------------- 窄屏兜底 ---------------- */
@media (max-width: 560px) {
  .page-about .ab-hero__facts {
    grid-template-columns: minmax(0, 1fr);
  }
  .page-about .ab-hero__title::after {
    width: 56px;
    height: 3px;
  }
  .page-about .ab-outro__act {
    flex-direction: column;
    align-items: stretch;
  }
  .page-about .ab-outro__btn,
  .page-about .ab-outro__btn2 {
    text-align: center;
  }
}