.page-about {
  --ab-rail: 236px;
  --ab-accent: var(--cyan);
  padding-block: clamp(16px, 2.6vw, 30px) clamp(52px, 7vw, 96px);
}

.page-about .breadcrumb {
  margin: 0 0 clamp(14px, 2vw, 22px);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  display: grid;
  gap: clamp(22px, 3.4vw, 44px);
  padding-bottom: clamp(26px, 4vw, 46px);
  border-bottom: 1px solid var(--line);
}

@media (min-width: 900px) {
  .page-about .ab-hero {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    align-items: end;
  }
}

.page-about .ab-hero__title {
  margin: 12px 0 0;
  font-size: clamp(27px, 6vw, 52px);
  font-weight: 900;
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--paper);
  text-shadow: 0 0 26px rgba(23, 230, 255, 0.2);
}

.page-about .ab-hero__lede {
  margin: clamp(12px, 1.8vw, 18px) 0 0;
  max-width: 33em;
  font-size: clamp(15px, 1.55vw, 17px);
  line-height: 1.85;
  color: var(--rock);
}

.page-about .ab-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border: 1px solid var(--line);
}

@media (min-width: 640px) {
  .page-about .ab-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .ab-stats li {
  background: var(--ink);
  padding: 12px 14px;
}

.page-about .ab-stat__v {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(19px, 2.5vw, 25px);
  font-weight: 700;
  line-height: 1.1;
  color: var(--amber);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
}

.page-about .ab-stat__l {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--rock);
}

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

/* ---------- 双栏骨架 ---------- */
.page-about .ab-layout {
  display: grid;
  gap: clamp(24px, 3vw, 44px);
  margin-top: clamp(30px, 4.5vw, 56px);
}

@media (min-width: 960px) {
  .page-about .ab-layout {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: clamp(34px, 4.4vw, 72px);
    align-items: start;
  }

  .page-about .ab-index {
    position: sticky;
    top: 24px;
  }
}

/* ---------- 章节索引 ---------- */
.page-about .ab-index {
  border-top: 2px solid var(--cyan);
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  border-left: 1px solid var(--line);
  background: var(--panel);
  padding: 16px 16px 18px;
}

.page-about .ab-index__label {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--rock);
}

.page-about .ab-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .ab-index__link {
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr);
  gap: 8px;
  align-items: baseline;
  min-height: 40px;
  padding: 9px 8px 9px 10px;
  border-left: 2px solid transparent;
  color: var(--paper);
  text-decoration: none;
  font-size: 14px;
  line-height: 1.4;
  transition: border-color var(--ease), background-color var(--ease), color var(--ease);
}

.page-about .ab-index__link:hover,
.page-about .ab-index__link:focus-visible {
  border-left-color: var(--cyan);
  background: rgba(23, 230, 255, 0.07);
  color: var(--cyan);
  outline: none;
}

.page-about .ab-index__n {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--rock);
}

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

.page-about .ab-index__foot {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

.page-about .ab-index__foot-label {
  margin: 0 0 4px;
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--rock);
}

.page-about .ab-hours {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--paper);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-copy {
  display: flex;
  width: 100%;
  min-height: 44px;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 9px 10px;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 11.5px;
  text-align: left;
  cursor: pointer;
  transition: border-color var(--ease), color var(--ease), background-color var(--ease);
}

.page-about .ab-copy:hover,
.page-about .ab-copy:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
  outline: none;
}

.page-about .ab-copy.is-copied {
  border-color: var(--moss);
  color: var(--moss);
}

.page-about .ab-copy__state {
  flex: none;
  padding: 2px 7px;
  border: 1px solid currentColor;
  border-radius: 999px;
  font-size: 11px;
  color: var(--rock);
}

.page-about .ab-copy.is-copied .ab-copy__state {
  color: var(--moss);
}

/* ---------- 章节 ---------- */
.page-about .ab-chapter {
  padding-block: clamp(26px, 3.6vw, 42px);
  border-top: 1px solid var(--line);
  scroll-margin-top: calc(var(--bar-h) + 16px);
}

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

.page-about .ab-chapter:nth-child(1) { --ab-accent: var(--cyan); }
.page-about .ab-chapter:nth-child(2) { --ab-accent: var(--moss); }
.page-about .ab-chapter:nth-child(3) { --ab-accent: var(--amber); }
.page-about .ab-chapter:nth-child(4) { --ab-accent: var(--magenta); }
.page-about .ab-chapter:nth-child(5) { --ab-accent: var(--clay); }

.page-about .ab-chapter__head {
  display: grid;
  grid-template-columns: 26px minmax(0, 1fr);
  gap: 0 12px;
  align-items: start;
  margin-bottom: clamp(14px, 2vw, 22px);
}

.page-about .ab-chapter__num {
  writing-mode: vertical-rl;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  line-height: 1;
  padding-top: 2px;
  color: var(--ab-accent);
}

.page-about .ab-chapter__title {
  margin: 0;
  font-size: clamp(20px, 2.8vw, 29px);
  font-weight: 800;
  line-height: 1.28;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .ab-p {
  margin: 0 0 14px;
  max-width: 36em;
  font-size: clamp(15px, 1.5vw, 16.5px);
  line-height: 1.85;
  color: rgba(243, 239, 230, 0.84);
}

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

.page-about .ab-p a {
  color: var(--cyan);
}

/* ---------- 三项服务 ---------- */
.page-about .ab-services {
  list-style: none;
  margin: clamp(16px, 2.4vw, 24px) 0 0;
  padding: 0;
}

.page-about .ab-svc {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 2px 14px;
  padding: 18px 0;
  border-top: 1px solid var(--line);
}

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

.page-about .ab-svc__n {
  font-family: var(--font-mono);
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 700;
  line-height: 1;
  color: var(--rock);
  font-variant-numeric: tabular-nums;
  transition: color var(--ease);
}

.page-about .ab-svc:hover .ab-svc__n,
.page-about .ab-svc:focus-within .ab-svc__n {
  color: var(--cyan);
}

.page-about .ab-svc__title {
  margin: 0 0 7px;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.45;
  color: var(--paper);
}

.page-about .ab-svc__text {
  margin: 0;
  max-width: 34em;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(243, 239, 230, 0.82);
}

.page-about .ab-svc__text a {
  color: var(--cyan);
}

.page-about .ab-svc__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 11px 0 0;
}

/* ---------- 时间线 ---------- */
.page-about .ab-timeline {
  position: relative;
  list-style: none;
  margin: clamp(16px, 2.4vw, 24px) 0 0;
  padding: 0;
}

.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 12px;
  bottom: 18px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan), var(--moss) 42%, var(--amber) 78%, var(--line));
}

.page-about .ab-node {
  display: grid;
  grid-template-columns: 16px minmax(0, 1fr);
  gap: 0 16px;
  padding-bottom: clamp(20px, 2.6vw, 30px);
}

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

.page-about .ab-node__dot {
  width: 9px;
  height: 9px;
  margin: 8px 0 0 3.5px;
  border: 1px solid var(--cyan);
  background: var(--ink);
  transform: rotate(45deg);
}

.page-about .ab-node:nth-child(2) .ab-node__dot { border-color: var(--moss); }
.page-about .ab-node:nth-child(3) .ab-node__dot { border-color: var(--amber); }
.page-about .ab-node:nth-child(4) .ab-node__dot { border-color: var(--magenta); }
.page-about .ab-node:nth-child(5) .ab-node__dot { border-color: var(--clay); }

.page-about .ab-node__year {
  margin: 0 0 4px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--amber);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-node__title {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.45;
  color: var(--paper);
}

.page-about .ab-node__text {
  margin: 0;
  max-width: 34em;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(243, 239, 230, 0.82);
}

.page-about .ab-node__aside {
  margin: 10px 0 0;
  padding-left: 10px;
  border-left: 1px solid var(--line);
  max-width: 30em;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--rock);
  transition: color var(--ease), border-color var(--ease), opacity var(--ease);
}

@media (hover: hover) and (min-width: 900px) {
  .page-about .ab-node__aside {
    opacity: 0.6;
  }

  .page-about .ab-node:hover .ab-node__aside,
  .page-about .ab-node:focus-within .ab-node__aside {
    opacity: 1;
    color: var(--paper);
    border-left-color: var(--amber);
  }
}

/* ---------- 插图 ---------- */
.page-about .ab-figure {
  margin: clamp(18px, 2.6vw, 28px) 0 0;
}

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

/* ---------- 收束区 ---------- */
.page-about .ab-cta {
  margin-top: clamp(32px, 4.6vw, 60px);
  padding: clamp(20px, 3vw, 32px);
  border: 1px solid var(--line);
  border-left: 2px solid var(--cyan);
  background:
    linear-gradient(135deg, rgba(23, 230, 255, 0.09), rgba(255, 46, 147, 0.06) 55%, rgba(6, 7, 10, 0) 78%),
    var(--panel);
}

.page-about .ab-cta__eyebrow {
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--rock);
}

.page-about .ab-cta__title {
  margin: 0 0 10px;
  font-size: clamp(20px, 3vw, 30px);
  font-weight: 800;
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .ab-cta__text {
  margin: 0;
  max-width: 38em;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(243, 239, 230, 0.8);
}

.page-about .ab-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: clamp(14px, 2vw, 20px);
}

@media (max-width: 520px) {
  .page-about .ab-cta__actions .btn {
    flex: 1 1 100%;
    justify-content: center;
  }
}

@media (max-width: 420px) {
  .page-about .ab-svc {
    grid-template-columns: 34px minmax(0, 1fr);
    gap: 2px 10px;
  }

  .page-about .ab-chapter__head {
    grid-template-columns: 20px minmax(0, 1fr);
    gap: 0 10px;
  }

  .page-about .ab-node {
    grid-template-columns: 14px minmax(0, 1fr);
    gap: 0 12px;
  }

  .page-about .ab-timeline::before {
    left: 7px;
  }

  .page-about .ab-node__dot {
    margin-left: 2.5px;
  }
}