.page-about {
  --ab-ruler-w: 156px;
  --ab-skew: -6deg;
  position: relative;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  padding-top: calc(var(--bar-h) + clamp(10px, 2vw, 22px));
}

.page-about .crumbs {
  margin-bottom: clamp(14px, 2.4vw, 26px);
}

/* ---------- Hero ---------- */

.page-about .ab-hero {
  position: relative;
  padding-bottom: clamp(34px, 6vw, 76px);
}

.page-about .ab-hero__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(18px, 3vw, 40px);
  align-items: start;
}

.page-about .ab-hero__eyebrow {
  margin: 0 0 clamp(12px, 2vw, 20px);
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--stone);
}

.page-about .ab-hero__title {
  margin: 0 0 clamp(16px, 2.4vw, 26px);
  font-family: var(--sans);
  font-weight: 900;
  font-size: clamp(32px, 7.2vw, 76px);
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--ink);
  max-width: 12em;
}

.page-about .ab-hero__lede {
  margin: 0 0 clamp(22px, 3.2vw, 34px);
  max-width: 33em;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.78;
  color: var(--ink-soft);
}

.page-about .ab-hero__stats {
  list-style: none;
  margin: 0 0 clamp(22px, 3.2vw, 34px);
  padding: clamp(16px, 2.2vw, 22px) 0 0;
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(14px, 2.4vw, 26px);
  max-width: 620px;
}

.page-about .ab-stat__num {
  display: block;
  font-family: var(--mono);
  font-size: clamp(26px, 3.4vw, 38px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: 0.01em;
  color: var(--clay-deep);
}

.page-about .ab-stat__num small {
  font-size: 0.46em;
  margin-left: 3px;
  color: var(--stone);
}

.page-about .ab-stat__label {
  display: block;
  margin-top: 5px;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--stone);
}

.page-about .ab-hero__cta {
  display: inline-block;
}

.page-about .ab-hero__aside {
  display: none;
}

/* ---------- 时间线 ---------- */

.page-about .ab-track {
  padding: clamp(30px, 5vw, 62px) 0 clamp(26px, 4vw, 54px);
  border-top: 1px solid var(--line);
}

.page-about .ab-track__head {
  max-width: 44em;
  margin-bottom: clamp(22px, 3.6vw, 44px);
}

.page-about .ab-track__title {
  margin: 0 0 12px;
  font-size: clamp(23px, 3.4vw, 38px);
  font-weight: 900;
  line-height: 1.2;
  letter-spacing: -0.015em;
  color: var(--ink);
}

.page-about .ab-track__intro {
  margin: 0;
  font-size: clamp(14px, 1.5vw, 16px);
  line-height: 1.78;
  color: var(--stone);
}

.page-about .ab-track__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(18px, 3vw, 40px);
  align-items: start;
}

/* 年份刻度尺：移动端横向索引 */
.page-about .ab-ruler {
  border-bottom: 1px solid var(--line);
  padding-bottom: 8px;
}

.page-about .ab-ruler__cap {
  display: none;
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: 0.24em;
  color: var(--stone);
}

.page-about .ab-ruler__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 16px;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .ab-ruler__list::-webkit-scrollbar {
  display: none;
}

.page-about .ab-ruler__item {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 4px 0;
  white-space: nowrap;
  text-decoration: none;
  color: var(--stone);
  font-size: 13px;
  transition: color 0.24s var(--ease);
}

.page-about .ab-ruler__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  border: 1px solid var(--stone);
  background: var(--paper);
  flex: none;
  transition: background 0.24s var(--ease), border-color 0.24s var(--ease), box-shadow 0.24s var(--ease);
}

.page-about .ab-ruler__year {
  font-family: var(--mono);
  letter-spacing: 0.08em;
}

.page-about .ab-ruler__note {
  display: none;
}

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

.page-about .ab-ruler__item:hover .ab-ruler__dot,
.page-about .ab-ruler__item:focus-visible .ab-ruler__dot {
  background: var(--cyan);
  border-color: var(--cyan);
  box-shadow: 0 0 0 4px rgba(18, 200, 206, 0.2);
}

/* 阶段内容 */
.page-about .ab-stages {
  min-width: 0;
}

.page-about .ab-stage {
  position: relative;
  padding: clamp(18px, 2.6vw, 28px) 0 clamp(20px, 3vw, 32px);
  border-top: 1px solid var(--line);
  scroll-margin-top: calc(var(--bar-h) + 24px);
}

.page-about .ab-stage:first-child {
  border-top: 0;
  padding-top: 0;
}

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

.page-about .ab-stage__year {
  display: inline-block;
  padding: 3px 10px;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  clip-path: polygon(0 0, 100% 0, 100% 100%, 9px 100%, 0 calc(100% - 9px));
}

.page-about .ab-stage__title {
  margin: 0 0 12px;
  font-size: clamp(19px, 2.6vw, 28px);
  font-weight: 900;
  line-height: 1.28;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .ab-stage p {
  margin: 0 0 12px;
  max-width: 34em;
  font-size: clamp(14px, 1.5vw, 16px);
  line-height: 1.8;
  color: var(--ink-soft);
}

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

.page-about .ab-inline-link {
  color: var(--clay-deep);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
  padding-bottom: 1px;
}

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

.page-about .ab-stage__figure {
  margin: 16px 0 0;
}

.page-about .ab-stage__figcap {
  margin: 8px 0 0;
  font-size: 12px;
  line-height: 1.6;
  color: var(--stone);
}

.page-about .ab-stage__figcap .mono {
  color: var(--moss);
  margin-right: 6px;
}

/* 图像带 */
.page-about .ab-band {
  margin: clamp(16px, 2.6vw, 30px) 0 clamp(20px, 3vw, 34px);
}

.page-about .ab-band__frame {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
}

.page-about .ab-band__frame::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(14, 27, 42, 0.12) 0%, rgba(14, 27, 42, 0.68) 100%);
  pointer-events: none;
}

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

.page-about .ab-band__cap {
  margin: 10px 0 0;
  display: flex;
  gap: 10px;
  align-items: baseline;
  font-size: 12px;
  line-height: 1.65;
  color: var(--stone);
}

.page-about .ab-band__cap .mono {
  color: var(--clay);
  letter-spacing: 0.12em;
}

/* ---------- 通用小标题 ---------- */

.page-about .ab-kicker {
  margin: 0 0 10px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.26em;
  color: var(--moss);
}

.page-about .ab-kicker--light {
  color: var(--cyan);
}

.page-about .ab-section-title {
  margin: 0 0 14px;
  font-size: clamp(22px, 3.2vw, 36px);
  font-weight: 900;
  line-height: 1.22;
  letter-spacing: -0.015em;
  color: var(--ink);
}

.page-about .ab-section-title--light {
  color: var(--paper);
}

/* ---------- 团队 ---------- */

.page-about .ab-team {
  background: var(--paper-2);
  padding: clamp(34px, 5.6vw, 76px) 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .ab-team__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3.6vw, 48px);
  align-items: start;
}

.page-about .ab-team__text {
  margin: 0 0 12px;
  max-width: 32em;
  font-size: clamp(14px, 1.5vw, 16px);
  line-height: 1.8;
  color: var(--ink-soft);
}

.page-about .ab-team__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .ab-team__item {
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  gap: 14px;
  align-items: center;
  background: var(--paper);
  border: 1px solid var(--line);
  box-shadow: 2px 2px 0 rgba(107, 103, 95, 0.09);
  padding: clamp(13px, 2vw, 18px);
}

.page-about .ab-team__item:first-child {
  grid-template-columns: 74px minmax(0, 1fr);
  border-left: 3px solid var(--clay);
}

.page-about .ab-team__num {
  font-family: var(--mono);
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 700;
  line-height: 1;
  color: var(--clay-deep);
}

.page-about .ab-team__body {
  display: block;
  min-width: 0;
}

.page-about .ab-team__body strong {
  display: block;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 4px;
}

.page-about .ab-team__body span {
  display: block;
  font-size: 13px;
  line-height: 1.65;
  color: var(--stone);
}

/* ---------- 反馈闭环 ---------- */

.page-about .ab-loop {
  padding: clamp(34px, 5.6vw, 76px) 0;
}

.page-about .ab-loop__head {
  max-width: 42em;
  margin-bottom: clamp(22px, 3.4vw, 40px);
}

.page-about .ab-loop__intro {
  margin: 0;
  font-size: clamp(14px, 1.5vw, 16px);
  line-height: 1.8;
  color: var(--stone);
}

.page-about .ab-loop__steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(16px, 2.4vw, 26px);
}

.page-about .ab-loop__step {
  border-top: 3px solid var(--moss);
  padding-top: 14px;
}

.page-about .ab-loop__step:nth-child(2) {
  border-top-color: var(--clay);
}

.page-about .ab-loop__step:nth-child(3) {
  border-top-color: var(--green);
}

.page-about .ab-loop__step:nth-child(4) {
  border-top-color: var(--cyan);
}

.page-about .ab-loop__num {
  display: block;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--stone);
  margin-bottom: 8px;
}

.page-about .ab-loop__step h3 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 900;
  color: var(--ink);
}

.page-about .ab-loop__step p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--ink-soft);
}

/* ---------- 覆盖与节点 ---------- */

.page-about .ab-cover {
  position: relative;
  background: var(--ink);
  color: var(--paper);
  padding: clamp(38px, 6vw, 84px) 0;
  overflow: hidden;
}

.page-about .ab-cover::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: linear-gradient(to right, rgba(18, 200, 206, 0.09) 1px, transparent 1px);
  background-size: 72px 100%;
  pointer-events: none;
}

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

.page-about .ab-cover__head {
  max-width: 46em;
  margin-bottom: clamp(22px, 3.4vw, 40px);
}

.page-about .ab-cover__text {
  margin: 0 0 12px;
  font-size: clamp(14px, 1.5vw, 16px);
  line-height: 1.82;
  color: rgba(245, 239, 230, 0.78);
}

.page-about .ab-cover__figure {
  margin: 0 0 clamp(22px, 3.4vw, 38px);
}

.page-about .ab-cover__frame {
  border: 1px solid rgba(18, 200, 206, 0.28);
  overflow: hidden;
}

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

.page-about .ab-cover__cap {
  margin: 10px 0 0;
  display: flex;
  gap: 10px;
  align-items: baseline;
  font-size: 12px;
  line-height: 1.6;
  color: rgba(245, 239, 230, 0.6);
}

.page-about .ab-cover__cap .mono {
  color: var(--cyan);
  letter-spacing: 0.12em;
}

.page-about .ab-cover__nodes {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px 18px;
}

.page-about .ab-cover__node {
  display: flex;
  align-items: center;
  gap: 8px;
  padding-top: 9px;
  border-top: 1px solid rgba(245, 239, 230, 0.18);
  font-size: 14px;
  color: var(--paper);
}

.page-about .ab-cover__node .mono {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: rgba(245, 239, 230, 0.45);
}

.page-about .ab-cover__beacon {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 0 3px rgba(47, 174, 107, 0.22);
  flex: none;
}

/* ---------- 下一年 ---------- */

.page-about .ab-next {
  position: relative;
  background: var(--loess);
  padding: clamp(38px, 6vw, 80px) 0;
}

.page-about .ab-next::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 5px;
  background: linear-gradient(90deg, var(--clay) 0%, var(--brick) 22%, var(--cyan) 58%, var(--green) 100%);
}

.page-about .ab-next__head {
  max-width: 42em;
  margin-bottom: clamp(22px, 3.4vw, 40px);
}

.page-about .ab-next__intro {
  margin: 0;
  font-size: clamp(14px, 1.5vw, 16px);
  line-height: 1.8;
  color: rgba(14, 27, 42, 0.72);
}

.page-about .ab-next__list {
  list-style: none;
  margin: 0 0 clamp(22px, 3.4vw, 38px);
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(14px, 2.2vw, 22px);
}

.page-about .ab-next__item {
  position: relative;
  background: var(--paper);
  border: 1px solid rgba(107, 103, 95, 0.28);
  box-shadow: 3px 3px 0 rgba(150, 54, 31, 0.14);
  padding: clamp(16px, 2.4vw, 24px);
}

.page-about .ab-next__num {
  display: inline-block;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--paper);
  background: var(--ink);
  padding: 2px 8px;
  margin-bottom: 10px;
}

.page-about .ab-next__item h3 {
  margin: 0 0 8px;
  font-size: clamp(16px, 2vw, 19px);
  font-weight: 900;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .ab-next__item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
  color: var(--ink-soft);
}

.page-about .ab-next__cta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}

/* ---------- 平板及以上 ---------- */

@media (min-width: 700px) {
  .page-about .ab-hero__stats {
    grid-template-columns: 1.1fr 1fr 0.9fr;
  }

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

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

@media (min-width: 860px) {
  .page-about .ab-hero__inner {
    grid-template-columns: minmax(0, 1fr) minmax(170px, 280px);
    gap: clamp(24px, 4vw, 56px);
  }

  .page-about .ab-hero__aside {
    display: block;
    position: relative;
    min-height: clamp(220px, 24vw, 300px);
  }

  .page-about .ab-hero__panel {
    position: absolute;
    inset: 0;
    background: linear-gradient(150deg, var(--clay) 0%, var(--loess) 100%);
    clip-path: polygon(0 7%, 100% 0, 100% 93%, 0 100%);
  }

  .page-about .ab-hero__pulse {
    position: absolute;
    left: 22%;
    top: 26%;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--ink);
    box-shadow: 0 0 0 0 rgba(14, 27, 42, 0.35);
    animation: ab-pulse 3s var(--ease) infinite;
  }

  .page-about .ab-hero__mark {
    position: absolute;
    left: 50%;
    bottom: 8%;
    transform: translateX(-50%);
    writing-mode: vertical-rl;
    margin: 0;
    font-size: 12px;
    letter-spacing: 0.3em;
    color: var(--ink);
    white-space: nowrap;
  }

  .page-about .ab-track__grid {
    grid-template-columns: var(--ab-ruler-w) minmax(0, 1fr);
    gap: clamp(30px, 4vw, 60px);
  }

  .page-about .ab-ruler {
    position: sticky;
    top: calc(var(--bar-h) + 36px);
    align-self: start;
    border-bottom: 0;
    padding-bottom: 0;
  }

  .page-about .ab-ruler__cap {
    display: block;
  }

  .page-about .ab-ruler__list {
    display: block;
    overflow: visible;
    position: relative;
    padding-left: 0;
  }

  .page-about .ab-ruler__list::before {
    content: "";
    position: absolute;
    left: 4px;
    top: 10px;
    bottom: 10px;
    width: 1px;
    background: var(--line);
  }

  .page-about .ab-ruler__item {
    position: relative;
    display: block;
    padding: 9px 0 9px 22px;
    white-space: normal;
  }

  .page-about .ab-ruler__dot {
    position: absolute;
    left: 0;
    top: 15px;
  }

  .page-about .ab-ruler__year {
    display: block;
    font-size: 14px;
  }

  .page-about .ab-ruler__note {
    display: block;
    font-size: 12px;
    line-height: 1.5;
    color: var(--stone);
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height 0.3s var(--ease), opacity 0.3s var(--ease), margin-top 0.3s var(--ease);
  }

  .page-about .ab-ruler__item:hover .ab-ruler__note,
  .page-about .ab-ruler__item:focus-visible .ab-ruler__note {
    max-height: 4em;
    opacity: 1;
    margin-top: 4px;
  }

  .page-about .ab-stage--split {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(170px, 220px);
    gap: clamp(20px, 3vw, 38px);
    align-items: start;
  }

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

  .page-about .ab-team__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr);
    gap: clamp(26px, 4vw, 60px);
  }

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

@media (min-width: 1040px) {
  .page-about .ab-loop__steps {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@keyframes ab-pulse {
  0% {
    box-shadow: 0 0 0 0 rgba(14, 27, 42, 0.35);
  }
  70% {
    box-shadow: 0 0 0 14px rgba(14, 27, 42, 0);
  }
  100% {
    box-shadow: 0 0 0 0 rgba(14, 27, 42, 0);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-hero__pulse {
    animation: none;
  }

  .page-about .ab-ruler__note,
  .page-about .ab-ruler__dot,
  .page-about .ab-ruler__item {
    transition: none;
  }
}