.page-about {
  --ab-rail-w: 208px;
  --ab-line: 1px solid var(--blueprint-line);
  --ab-soft-line: 1px solid rgba(31, 74, 107, 0.55);
  background: var(--ink-900);
  color: var(--cream);
  font-family: var(--font-body);
  overflow-wrap: break-word;
}
.page-about *,
.page-about *::before,
.page-about *::after { box-sizing: border-box; }

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

/* ---------- 面包屑 ---------- */
.page-about .crumb {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 18px 0 0;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--slate-muted);
}
.page-about .crumb a { color: var(--slate-muted); text-decoration: none; }
.page-about .crumb a:hover { color: var(--cyan-live); }
.page-about .crumb__sep { color: var(--blueprint-line); }
.page-about .crumb [aria-current="page"] { color: var(--cyan-live); }

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  padding-bottom: 28px;
  border-bottom: var(--ab-line);
  background:
    repeating-linear-gradient(90deg, rgba(31, 74, 107, 0.22) 0 1px, transparent 1px 72px),
    linear-gradient(180deg, rgba(14, 36, 56, 0.95) 0%, rgba(7, 24, 43, 1) 78%);
}
.page-about .ab-hero__grid {
  display: grid;
  gap: 24px;
  padding: 22px 0 0;
}
.page-about .ab-hero__eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.2em;
  color: var(--slate-muted);
  text-transform: uppercase;
}
.page-about .ab-hero__code {
  display: inline-block;
  padding: 3px 8px;
  background: var(--orange-signal);
  color: #1a0c05;
  letter-spacing: 0.14em;
  clip-path: polygon(0 0, 100% 0, calc(100% - 7px) 100%, 0 100%);
}
.page-about .ab-hero h1 {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: var(--fs-31);
  line-height: 1.18;
  letter-spacing: -0.01em;
  color: var(--cream);
}
.page-about .ab-hero__sub {
  max-width: 46em;
  margin: 16px 0 0;
  font-size: var(--fs-16);
  line-height: 1.75;
  color: var(--slate-muted);
}
.page-about .ab-hero__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 24px 0 0;
  padding: 1px;
  list-style: none;
  background: var(--blueprint-line);
}
.page-about .ab-hero__stats li {
  padding: 12px 14px;
  background: var(--panel-blue);
}
.page-about .ab-hero__stats .num {
  display: block;
  font-size: var(--fs-25);
  font-weight: 700;
  line-height: 1.1;
  color: var(--cyan-live);
}
.page-about .ab-hero__stats span:last-child {
  display: block;
  margin-top: 6px;
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--slate-muted);
}

.page-about .ab-hero__visual {
  position: relative;
  min-height: 190px;
  border: var(--ab-line);
  background: linear-gradient(160deg, rgba(14, 36, 56, 0.95), rgba(7, 24, 43, 0.55));
  clip-path: polygon(0 5%, 100% 0, 100% 100%, 0 95%);
  overflow: hidden;
}
.page-about .ab-hero__svg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.page-about .ab-hero__media {
  margin: 26px 0 0;
}
.page-about .ab-hero__media .media__frame {
  aspect-ratio: 2 / 1;
}
.page-about .media img {
  display: block;
  width: 100%;
  height: 100%;
  max-width: 100%;
  object-fit: cover;
}
.page-about .media__cap {
  margin: 10px 0 0;
  font-size: var(--fs-12);
  line-height: 1.7;
  letter-spacing: 0.04em;
  color: var(--slate-muted);
}

/* ---------- 主布局与左侧索引 ---------- */
.page-about .ab-layout {
  display: grid;
  gap: 28px;
  padding-block: 32px 64px;
}
.page-about .ab-rail {
  display: grid;
  gap: 18px;
  padding-top: 14px;
  border-top: var(--ab-line);
  min-width: 0;
}
.page-about .ab-rail__title,
.page-about .ab-scale__title {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--slate-muted);
}
.page-about .ab-rail__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.page-about .ab-rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 7px 10px;
  border: var(--ab-line);
  font-size: var(--fs-12);
  color: var(--slate-muted);
  text-decoration: none;
  transition: color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease), background var(--t-fast) var(--ease);
}
.page-about .ab-rail__idx {
  font-family: var(--font-mono);
  letter-spacing: 0.1em;
  color: var(--blueprint-line);
}
.page-about .ab-rail__link:hover,
.page-about .ab-rail__link:focus-visible {
  color: var(--cyan-live);
  border-color: var(--cyan-live);
  background: rgba(41, 231, 255, 0.07);
}
.page-about .ab-rail__link[aria-current="location"] {
  color: var(--ink-900);
  background: var(--cyan-live);
  border-color: var(--cyan-live);
}
.page-about .ab-rail__link[aria-current="location"] .ab-rail__idx { color: rgba(7, 24, 43, 0.7); }

.page-about .ab-scale {
  padding-top: 14px;
  border-top: var(--ab-soft-line);
}
.page-about .ab-scale__list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
}
.page-about .ab-scale__item {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 5px 9px;
  font-size: var(--fs-15);
  color: var(--cream);
  text-decoration: none;
  border: var(--ab-line);
  transition: border-color var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}
.page-about .ab-scale__dot {
  width: 7px;
  height: 7px;
  background: var(--orange-signal);
  clip-path: polygon(50% 0, 100% 50%, 50% 100%, 0 50%);
}
.page-about .ab-scale__item:hover,
.page-about .ab-scale__item:focus-visible { border-color: var(--cyan-live); color: var(--cyan-live); }
.page-about .ab-scale__item[aria-current="location"] { border-color: var(--cyan-live); color: var(--cyan-live); }
.page-about .ab-scale__foot {
  margin: 14px 0 0;
  font-size: var(--fs-12);
  letter-spacing: 0.22em;
  color: var(--slate-muted);
}

/* ---------- 章节通用 ---------- */
.page-about .ab-flow { min-width: 0; }
.page-about .ab-sec { padding-bottom: 40px; }
.page-about .ab-sec + .ab-sec {
  padding-top: 36px;
  border-top: var(--ab-soft-line);
}
.page-about .ab-sec .sec-head__title {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: var(--fs-25);
  line-height: 1.25;
  letter-spacing: -0.005em;
  margin: 8px 0 0;
}
.page-about .ab-sec .sec-head__idx {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.18em;
  color: var(--orange-signal);
}
.page-about .ab-lede {
  margin: 18px 0 0;
  font-size: var(--fs-16);
  line-height: 1.85;
  color: var(--slate-muted);
}

/* ---------- 01 上线路程 ---------- */
.page-about .ab-flowchart {
  display: grid;
  gap: 14px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}
.page-about .ab-step {
  position: relative;
  padding: 16px 18px;
  border: var(--ab-line);
  background: var(--panel-blue);
  border-left: 3px solid var(--blueprint-line);
}
.page-about .ab-step__num {
  font-size: var(--fs-12);
  letter-spacing: 0.2em;
  color: var(--cyan-live);
}
.page-about .ab-step__title {
  margin: 8px 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: var(--fs-20);
  color: var(--cream);
}
.page-about .ab-step p {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.8;
  color: var(--slate-muted);
}

.page-about .ab-glass {
  margin-top: 18px;
  padding: 16px 18px;
  border: 1px solid rgba(41, 231, 255, 0.35);
  border-left: 3px solid var(--cyan-live);
  background: rgba(14, 36, 56, 0.55);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}
.page-about .ab-glass__label {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cyan-live);
}
.page-about .ab-glass p:last-child {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.8;
  color: var(--cream);
}

/* ---------- 02 版本时间轴（奶油纸面） ---------- */
.page-about .ab-paper {
  padding: 26px 20px 30px;
  background: var(--cream);
  color: var(--brown-ink);
  border-left: 4px solid var(--orange-signal);
}
.page-about .ab-paper .sec-head__idx { color: #b0491c; }
.page-about .ab-paper .sec-head__title { color: var(--brown-ink); }
.page-about .ab-paper__lede {
  margin: 16px 0 0;
  font-size: var(--fs-16);
  line-height: 1.85;
  color: #4a3c32;
}
.page-about .ab-tl__svg {
  display: block;
  width: 100%;
  height: auto;
  margin: 22px 0 0;
}
.page-about .ab-tl__legend {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  margin: 14px 0 0;
  padding: 0;
  list-style: none;
  font-size: var(--fs-12);
  color: #4a3c32;
}
.page-about .ab-tl__legend li { display: inline-flex; align-items: center; gap: 7px; }
.page-about .ab-tl__key { width: 11px; height: 11px; border-radius: 50%; display: inline-block; }
.page-about .ab-tl__key--solid { background: #ff6a2c; }
.page-about .ab-tl__key--hollow { background: var(--cream); border: 2px solid var(--brown-ink); }

.page-about .ab-tl__list {
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid rgba(36, 28, 22, 0.2);
}
.page-about .ab-tl__item {
  display: grid;
  gap: 6px;
  padding: 18px 0;
  border-bottom: 1px solid rgba(36, 28, 22, 0.2);
  scroll-margin-top: calc(var(--cmd-h) + 24px);
}
.page-about .ab-tl__year {
  font-size: var(--fs-31);
  font-weight: 700;
  line-height: 1;
  color: #b0491c;
}
.page-about .ab-tl__body h3 {
  margin: 4px 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: var(--fs-20);
  color: var(--brown-ink);
}
.page-about .ab-tl__body p {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.8;
  color: #4a3c32;
}
.page-about .ab-tl__tag {
  display: inline-block;
  margin-top: 10px;
  padding: 3px 9px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: #fff;
  background: var(--orange-signal);
}
.page-about .ab-tl__tag--hollow {
  background: transparent;
  color: var(--brown-ink);
  border: 1px solid var(--brown-ink);
}

/* ---------- 03 口径规则 ---------- */
.page-about .ab-rules {
  display: grid;
  gap: 26px;
  margin-top: 20px;
}
.page-about .ab-rules__text p {
  margin: 0 0 16px;
  font-size: var(--fs-16);
  line-height: 1.85;
  color: var(--slate-muted);
}
.page-about .ab-rules__media { margin: 0; }
.page-about .ab-rules__media .media__frame { aspect-ratio: 1 / 1; }

.page-about .ab-acc {
  margin-top: 6px;
  border: var(--ab-line);
  background: rgba(14, 36, 56, 0.6);
}
.page-about .ab-acc__sum {
  display: block;
  padding: 12px 14px;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  color: var(--cyan-live);
  text-transform: uppercase;
}
.page-about .ab-acc__sum::-webkit-details-marker { display: none; }
.page-about .ab-acc__sum::after {
  content: "＋";
  float: right;
  color: var(--slate-muted);
}
.page-about .ab-acc[open] .ab-acc__sum::after { content: "－"; }
.page-about .ab-acc__sum:focus-visible { outline: 2px solid var(--cyan-live); outline-offset: 2px; }

.page-about .ab-fields {
  margin: 0;
  padding: 0 14px 12px;
}
.page-about .ab-fields__row {
  display: grid;
  gap: 2px;
  padding: 10px 0;
  border-top: var(--ab-soft-line);
}
.page-about .ab-fields__row dt {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--cyan-live);
}
.page-about .ab-fields__row dd {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.7;
  color: var(--slate-muted);
}

.page-about .ab-flag {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  gap: 10px;
  margin-top: 18px;
  padding: 14px 16px;
  border: 1px solid rgba(255, 194, 75, 0.5);
  background: rgba(255, 194, 75, 0.07);
}
.page-about .ab-flag__badge {
  flex: none;
  padding: 2px 8px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.12em;
  color: #22190a;
  background: var(--amber-flag);
}
.page-about .ab-flag p {
  flex: 1 1 240px;
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.75;
  color: var(--cream);
}

/* ---------- 04 团队分工 ---------- */
.page-about .ab-team {
  display: grid;
  gap: 26px;
  margin-top: 4px;
}
.page-about .ab-roles {
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid rgba(36, 28, 22, 0.2);
}
.page-about .ab-role {
  padding: 16px 0;
  border-bottom: 1px solid rgba(36, 28, 22, 0.2);
}
.page-about .ab-role__tag {
  font-size: var(--fs-12);
  letter-spacing: 0.2em;
  color: #b0491c;
}
.page-about .ab-role__title {
  margin: 6px 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: var(--fs-20);
  color: var(--brown-ink);
}
.page-about .ab-role p {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.8;
  color: #4a3c32;
}

.page-about .ab-team__media {
  position: relative;
  margin: 0;
}
.page-about .ab-team__media .media__frame { aspect-ratio: 3 / 2; }
.page-about .ab-gloss { }
.page-about .ab-glass--float {
  margin-top: 16px;
  background: rgba(36, 28, 22, 0.9);
  border-color: rgba(41, 231, 255, 0.42);
}
.page-about .ab-glass--float p:last-child { color: var(--cream); }

/* ---------- 05 站点边界 ---------- */
.page-about .ab-limits__list {
  display: grid;
  gap: 1px;
  margin: 22px 0 0;
  padding: 1px;
  list-style: none;
  background: var(--blueprint-line);
}
.page-about .ab-limits__item {
  padding: 18px 18px 18px 22px;
  background: var(--panel-blue);
  position: relative;
}
.page-about .ab-limits__item::before {
  content: "";
  position: absolute;
  left: 10px;
  top: 24px;
  width: 6px;
  height: 6px;
  background: var(--orange-signal);
  clip-path: polygon(50% 0, 100% 50%, 50% 100%, 0 50%);
}
.page-about .ab-limits__item h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: var(--fs-20);
  color: var(--cream);
}
.page-about .ab-limits__item p {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.8;
  color: var(--slate-muted);
}

.page-about .ab-links {
  margin-top: 28px;
  padding-top: 20px;
  border-top: 1px dashed rgba(31, 74, 107, 0.9);
}
.page-about .ab-links__title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--slate-muted);
}
.page-about .ab-links__list {
  display: grid;
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--blueprint-line);
}
.page-about .ab-links__list a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 13px 16px;
  background: var(--ink-900);
  font-size: var(--fs-15);
  color: var(--cream);
  text-decoration: none;
  transition: background var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}
.page-about .ab-links__list a span { color: var(--orange-signal); }
.page-about .ab-links__list a:hover,
.page-about .ab-links__list a:focus-visible {
  background: var(--panel-blue);
  color: var(--cyan-live);
}

.page-about a:focus-visible {
  outline: 2px solid var(--cyan-live);
  outline-offset: 2px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .ab-hero__stats { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .page-about .ab-flowchart { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; }
  .page-about .ab-step + .ab-step::before {
    content: "";
    position: absolute;
    left: -12px;
    top: 46px;
    width: 8px;
    height: 1px;
    background: var(--blueprint-line);
  }
  .page-about .ab-step + .ab-step::after {
    content: "";
    position: absolute;
    left: -16px;
    top: 43px;
    width: 5px;
    height: 5px;
    background: var(--cyan-live);
    clip-path: polygon(0 0, 100% 50%, 0 100%);
  }
  .page-about .ab-fields__row { grid-template-columns: 152px minmax(0, 1fr); align-items: baseline; gap: 16px; }
  .page-about .ab-tl__item { grid-template-columns: 120px minmax(0, 1fr); gap: 20px; align-items: start; }
  .page-about .ab-tl__year { font-size: var(--fs-39); }
  .page-about .ab-limits__list { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .page-about .ab-links__list { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .page-about .ab-paper { padding: 30px 28px 34px; }
}

@media (min-width: 900px) {
  .page-about .ab-hero h1 { font-size: var(--fs-39); }
  .page-about .ab-hero__grid { grid-template-columns: 8fr 4fr; gap: 40px; align-items: start; }
  .page-about .ab-hero__visual { min-height: 300px; }
  .page-about .ab-rules { grid-template-columns: 5fr 7fr; gap: 34px; align-items: start; }
  .page-about .ab-team { grid-template-columns: 7fr 5fr; gap: 34px; align-items: start; }
  .page-about .ab-sec .sec-head__title { font-size: var(--fs-31); }
}

@media (min-width: 1000px) {
  .page-about .ab-layout {
    grid-template-columns: var(--ab-rail-w) minmax(0, 1fr);
    gap: 52px;
    align-items: start;
    padding-block: 44px 80px;
  }
  .page-about .ab-rail {
    position: sticky;
    top: calc(var(--cmd-h) + 24px);
    padding-top: 18px;
    border-top: none;
    border-left: var(--ab-line);
    padding-left: 16px;
  }
  .page-about .ab-rail__list {
    display: grid;
    gap: 2px;
  }
  .page-about .ab-rail__link {
    justify-content: flex-start;
    width: 100%;
    padding: 8px 0 8px 10px;
    border: none;
    border-left: 2px solid transparent;
    font-size: var(--fs-15);
  }
  .page-about .ab-rail__link:hover,
  .page-about .ab-rail__link:focus-visible {
    background: rgba(41, 231, 255, 0.06);
    border-left-color: var(--cyan-live);
  }
  .page-about .ab-rail__link[aria-current="location"] {
    background: rgba(41, 231, 255, 0.12);
    border-left-color: var(--cyan-live);
    color: var(--cyan-live);
  }
  .page-about .ab-rail__link[aria-current="location"] .ab-rail__idx { color: var(--orange-signal); }
  .page-about .ab-scale__list {
    display: grid;
    gap: 2px;
    position: relative;
    padding-left: 14px;
  }
  .page-about .ab-scale__list::before {
    content: "";
    position: absolute;
    left: 3px;
    top: 6px;
    bottom: 6px;
    width: 1px;
    background: var(--blueprint-line);
  }
  .page-about .ab-scale__item {
    border: none;
    padding: 4px 0;
    font-size: var(--fs-15);
    color: var(--slate-muted);
    position: relative;
  }
  .page-about .ab-scale__dot {
    position: absolute;
    left: -14px;
    top: 50%;
    transform: translateY(-50%);
  }
  .page-about .ab-scale__item:hover,
  .page-about .ab-scale__item:focus-visible { color: var(--cyan-live); }
  .page-about .ab-scale__item[aria-current="location"] { color: var(--cyan-live); }
  .page-about .ab-glass--float {
    position: absolute;
    left: -28px;
    bottom: -24px;
    width: min(320px, 88%);
    margin: 0;
    box-shadow: 0 18px 40px rgba(0, 0, 0, 0.35);
  }
  .page-about .ab-team__media { padding-bottom: 26px; }
}

@media (min-width: 1200px) {
  .page-about .ab-hero h1 { font-size: var(--fs-49); }
  .page-about .ab-paper { padding: 36px 40px 40px; }
  .page-about .ab-tl__list { margin-top: 30px; }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-rail__link,
  .page-about .ab-scale__item,
  .page-about .ab-links__list a {
    transition: none;
  }
}
</main>