.page-about {
  --ab-line: rgba(42, 33, 28, 0.22);
  --ab-line-soft: rgba(42, 33, 28, 0.1);
  --ab-pad: 18px;
  color: var(--ink);
  padding-bottom: 56px;
}

.page-about .crumbs {
  margin-bottom: 16px;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  padding: var(--ab-pad);
  background: var(--paper-lift);
}

.page-about .ab-hero__grid {
  display: grid;
  gap: 22px;
  min-width: 0;
}

.page-about .ab-hero__intro h1 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(28px, 6.4vw, 46px);
  line-height: 1.18;
  letter-spacing: -0.01em;
  margin: 10px 0 14px;
}

.page-about .ab-hero__intro .lede {
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink-soft);
  margin: 0 0 20px;
}

.page-about .ab-chips {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(92px, 1fr));
  gap: 12px 16px;
}

.page-about .ab-chip {
  border-top: 2px solid var(--ink);
  padding-top: 8px;
}

.page-about .ab-chip__n {
  display: block;
  font-size: 22px;
  line-height: 1.1;
  color: var(--red);
}

.page-about .ab-chip__k {
  display: block;
  font-size: 12px;
  letter-spacing: 0.02em;
  color: var(--ink-soft);
  margin-top: 2px;
}

/* ---------- 图片容器 ---------- */
.page-about .ab-figure {
  margin: 0;
}

.page-about .ab-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--ab-line);
  background: var(--night);
}

.page-about .ab-figure__cap {
  font-family: var(--font-label);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ash);
  border-top: 1px solid var(--ab-line-soft);
  margin-top: 8px;
  padding-top: 6px;
}

/* ---------- 主体双栏 ---------- */
.page-about .ab-body {
  display: grid;
  gap: 26px;
  margin-top: 30px;
  min-width: 0;
}

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

/* ---------- 章节目录 ---------- */
.page-about .ab-nav {
  position: sticky;
  top: var(--bar-h);
  z-index: 6;
  background: var(--paper);
  border-bottom: 1px solid var(--ab-line);
  padding: 8px 0 10px;
  margin-bottom: 4px;
}

.page-about .ab-nav__title {
  font-family: var(--font-label);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ash);
  margin: 0 0 6px;
}

.page-about .ab-nav__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 18px;
  overflow-x: auto;
  scrollbar-width: none;
}

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

.page-about .ab-nav__list li {
  flex: 0 0 auto;
}

.page-about .ab-nav__link {
  display: flex;
  align-items: baseline;
  gap: 6px;
  white-space: nowrap;
  padding: 6px 2px;
  border-bottom: 2px solid transparent;
  font-family: var(--font-label);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
  text-decoration: none;
  transition: color 160ms ease, border-color 160ms ease;
}

.page-about .ab-nav__no {
  font-size: 11px;
  color: var(--ash);
}

.page-about .ab-nav__link:hover {
  color: var(--red);
}

.page-about .ab-nav__link[aria-current="location"] {
  color: var(--red);
  border-bottom-color: var(--red);
}

.page-about .ab-nav__link[aria-current="location"] .ab-nav__no {
  color: var(--red);
}

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

/* ---------- 章节通用 ---------- */
.page-about .ab-sec {
  padding: 28px 0 10px;
  border-top: 1px dashed var(--ab-line);
  scroll-margin-top: calc(var(--bar-h) + 64px);
}

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

.page-about .ab-sec--flush {
  padding-left: 0;
  padding-right: 0;
}

.page-about .ab-prose {
  font-size: 15px;
  line-height: 1.82;
  color: var(--ink-soft);
  margin: 14px 0 0;
}

.page-about .ab-sec h2 {
  margin: 0;
}

.page-about .ab-sec h3 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 17px;
  margin: 0 0 6px;
}

.page-about .ab-keyline {
  list-style: none;
  margin: 20px 0 0;
  padding: 14px 0 0;
  border-top: 1px solid var(--ab-line-soft);
  display: grid;
  gap: 8px;
  font-size: 13px;
  color: var(--ink-soft);
}

.page-about .ab-keyline .num {
  color: var(--red);
  margin-right: 6px;
}

/* ---------- 收录口径 ---------- */
.page-about .ab-rulecols {
  display: grid;
  gap: 26px;
  margin-top: 20px;
}

.page-about .ab-rulecol__t {
  margin: 0 0 6px;
  font-weight: 400;
}

.page-about .ab-rule {
  border-top: 1px solid var(--ab-line-soft);
}

.page-about .ab-rule summary {
  display: grid;
  grid-template-columns: 32px minmax(0, 1fr) 16px;
  gap: 8px;
  align-items: baseline;
  padding: 11px 0;
  cursor: pointer;
  font-size: 14.5px;
  color: var(--ink);
  list-style: none;
}

.page-about .ab-rule summary::-webkit-details-marker {
  display: none;
}

.page-about .ab-rule summary::after {
  content: "+";
  font-family: var(--font-num);
  font-size: 14px;
  color: var(--ash);
  text-align: right;
}

.page-about .ab-rule[open] summary::after {
  content: "–";
  color: var(--red);
}

.page-about .ab-rule__no {
  font-size: 12px;
  color: var(--red);
}

.page-about .ab-rule__t::before {
  content: "— ";
  color: var(--ash);
}

.page-about .ab-rule__body {
  margin: 0 0 14px 40px;
  font-size: 13.5px;
  line-height: 1.78;
  color: var(--ink-soft);
  border-left: 2px solid var(--ab-line-soft);
  padding-left: 12px;
}

.page-about .ab-rulecol--out .ab-rule__no {
  color: var(--indigo);
}

/* ---------- 三级校核（深色面板） ---------- */
.page-about .ab-night {
  background: var(--night);
  padding: 24px var(--ab-pad) 26px;
  color: var(--paper);
}

.page-about .ab-night .sec-head__no {
  color: var(--orange);
}

.page-about .ab-night .sec-head__title {
  color: var(--paper);
}

.page-about .ab-night .sec-head__note {
  color: rgba(244, 239, 230, 0.58);
}

.page-about .ab-night__lede {
  font-size: 15px;
  line-height: 1.82;
  color: rgba(244, 239, 230, 0.78);
  margin: 14px 0 0;
}

.page-about .ab-steps {
  display: grid;
  gap: 2px;
  margin-top: 22px;
}

.page-about .ab-step {
  border-top: 2px solid rgba(244, 239, 230, 0.22);
  padding: 14px 0 16px;
}

.page-about .ab-step__no {
  display: block;
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--orange);
  margin-bottom: 6px;
}

.page-about .ab-step__t {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 600;
  color: var(--paper);
  margin: 0 0 8px;
}

.page-about .ab-step__d {
  font-size: 13.5px;
  line-height: 1.78;
  color: rgba(244, 239, 230, 0.74);
  margin: 0;
}

/* ---------- 小组分工 ---------- */
.page-about .ab-teamwrap {
  display: grid;
  gap: 22px;
  margin-top: 6px;
  min-width: 0;
}

.page-about .ab-team {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
}

.page-about .ab-team__item {
  background: var(--paper-lift);
  border: 1px solid var(--ab-line);
  padding: 14px;
}

.page-about .ab-team__n {
  display: block;
  font-size: 34px;
  line-height: 1;
  color: var(--red);
  letter-spacing: -0.02em;
}

.page-about .ab-team__t {
  margin: 8px 0 4px;
  font-size: 15px;
}

.page-about .ab-team__item p {
  margin: 0;
  font-size: 13px;
  line-height: 1.72;
  color: var(--ink-soft);
}

.page-about .ab-team__fig img {
  border-color: var(--ink);
}

/* ---------- 阶段带 ---------- */
.page-about .ab-stages {
  display: flex;
  gap: 3px;
  overflow-x: auto;
  padding-bottom: 8px;
  margin-top: 20px;
  scroll-snap-type: x proximity;
}

.page-about .ab-stage {
  flex: 1 0 132px;
  scroll-snap-align: start;
  display: block;
  text-decoration: none;
  color: var(--paper);
  padding: 12px 11px 14px;
  min-height: 92px;
  transition: transform 180ms ease, filter 180ms ease;
}

.page-about .ab-stage:hover,
.page-about .ab-stage:focus-visible {
  transform: translateY(-3px);
  filter: saturate(1.1);
}

.page-about .ab-stage__no {
  display: block;
  font-size: 12px;
  opacity: 0.8;
  margin-bottom: 16px;
}

.page-about .ab-stage__t {
  font-family: var(--font-label);
  font-size: 13px;
  letter-spacing: 0.04em;
}

.page-about .ab-stage--1 { background: var(--orange); }
.page-about .ab-stage--2 { background: var(--red); }
.page-about .ab-stage--3 { background: var(--red-deep); }
.page-about .ab-stage--4 { background: var(--indigo); }
.page-about .ab-stage--5 { background: var(--night); border: 1px solid rgba(244, 239, 230, 0.28); }

.page-about .ab-stagelist {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 0;
  counter-reset: none;
}

.page-about .ab-stagelist__item {
  border-top: 1px solid var(--ab-line-soft);
  padding: 14px 0 16px;
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 4px 12px;
  scroll-margin-top: calc(var(--bar-h) + 70px);
}

.page-about .ab-stagelist__no {
  grid-row: span 2;
  font-size: 22px;
  line-height: 1.2;
  color: var(--ash);
}

.page-about .ab-stagelist__item h3 {
  margin: 0;
  font-size: 16px;
}

.page-about .ab-stagelist__item p {
  grid-column: 2;
  margin: 4px 0 0;
  font-size: 13.5px;
  line-height: 1.78;
  color: var(--ink-soft);
}

.page-about .ab-stagelist__item:target {
  background: rgba(224, 102, 42, 0.08);
}

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

/* ---------- 覆盖范围 ---------- */
.page-about .ab-tablescroll {
  overflow-x: auto;
  margin-top: 20px;
  border-top: 2px solid var(--ink);
}

.page-about .ab-table {
  width: 100%;
  min-width: 460px;
  border-collapse: collapse;
  font-size: 14px;
}

.page-about .ab-table__cap {
  text-align: left;
  font-family: var(--font-label);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ash);
  padding: 10px 0 6px;
}

.page-about .ab-table th,
.page-about .ab-table td {
  padding: 10px 8px;
  text-align: left;
  border-bottom: 1px solid var(--ab-line-soft);
}

.page-about .ab-table thead th {
  font-family: var(--font-label);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
  border-bottom: 1px solid var(--ab-line);
  white-space: nowrap;
}

.page-about .ab-table tbody th {
  font-weight: 600;
  color: var(--ink);
}

.page-about .ab-n {
  text-align: right;
  font-size: 15px;
  color: var(--ink);
}

.page-about .ab-table tfoot th,
.page-about .ab-table tfoot td {
  border-top: 2px solid var(--ink);
  border-bottom: 0;
  font-weight: 700;
  color: var(--ink);
}

.page-about .ab-rhythm {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .ab-rhythm li {
  display: grid;
  gap: 2px;
  border-left: 2px solid var(--orange);
  padding-left: 12px;
}

.page-about .ab-rhythm__k {
  font-family: var(--font-label);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--red);
}

.page-about .ab-rhythm__v {
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--ink-soft);
}

/* ---------- 反馈路径 ---------- */
.page-about .ab-feedback {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  display: grid;
  gap: 4px;
}

.page-about .ab-feedback__item {
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr);
  gap: 10px;
  border-top: 1px solid var(--ab-line-soft);
  padding: 14px 0;
}

.page-about .ab-feedback__no {
  font-size: 16px;
  color: var(--red);
  line-height: 1.5;
}

.page-about .ab-feedback__item h3 {
  margin: 0 0 4px;
  font-size: 15px;
}

.page-about .ab-feedback__item p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.78;
  color: var(--ink-soft);
}

.page-about .ab-feedback__item a {
  color: var(--red);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .ab-next {
  margin-top: 26px;
  border-top: 2px solid var(--ink);
  padding-top: 14px;
}

.page-about .ab-next__t {
  font-family: var(--font-label);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ash);
  margin: 0 0 10px;
}

.page-about .ab-next__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.page-about .ab-next__list li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  font-size: 13.5px;
}

.page-about .ab-next__list a {
  font-weight: 600;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 2px solid var(--red);
  padding-bottom: 1px;
}

.page-about .ab-next__list span {
  color: var(--ink-soft);
}

/* ---------- 平板与桌面 ---------- */
@media (min-width: 640px) {
  .page-about {
    --ab-pad: 26px;
  }

  .page-about .ab-hero__grid {
    gap: 26px;
  }

  .page-about .ab-steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
  }

  .page-about .ab-step {
    border-top-width: 2px;
    padding-right: 12px;
  }

  .page-about .ab-stagelist__item {
    grid-template-columns: 56px minmax(0, 1fr);
  }
}

@media (min-width: 900px) {
  .page-about {
    padding-bottom: 72px;
  }

  .page-about .ab-hero__grid {
    grid-template-columns: 5fr 6fr;
    align-items: start;
    gap: 34px;
  }

  .page-about .ab-rulecols {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 34px;
  }

  .page-about .ab-teamwrap {
    grid-template-columns: minmax(0, 1fr) 248px;
    gap: 30px;
    align-items: start;
  }

  .page-about .ab-team__fig {
    margin-top: 20px;
  }

  .page-about .ab-stages {
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    overflow: visible;
    gap: 4px;
  }

  .page-about .ab-stage {
    flex: initial;
    min-height: 108px;
  }

  .page-about .ab-rhythm {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px 26px;
  }
}

@media (min-width: 1000px) {
  .page-about .ab-body {
    grid-template-columns: 196px minmax(0, 1fr);
    gap: 46px;
    margin-top: 46px;
  }

  .page-about .ab-nav {
    position: sticky;
    top: 24px;
    border-bottom: 0;
    padding: 0;
    margin-bottom: 0;
    background: transparent;
  }

  .page-about .ab-nav__list {
    display: block;
    overflow: visible;
  }

  .page-about .ab-nav__link {
    justify-content: flex-start;
    padding: 8px 10px;
    border-bottom: 0;
    border-left: 2px solid transparent;
  }

  .page-about .ab-nav__link[aria-current="location"] {
    border-bottom-color: transparent;
    border-left-color: var(--red);
  }

  .page-about .ab-track {
    display: block;
    height: 3px;
    background: var(--ab-line-soft);
    margin-top: 14px;
  }

  .page-about .ab-track__fill {
    display: block;
    width: 0;
    height: 100%;
    background: var(--red);
  }
}