.page-about {
  --ab-lime-50: rgba(200, 255, 61, 0.5);
  --ab-lime-26: rgba(200, 255, 61, 0.26);
  --ab-orange-18: rgba(255, 154, 60, 0.18);
  background: var(--c-ink);
  color: var(--c-body);
  font-family: var(--f-body);
  line-height: 1.75;
  padding-bottom: clamp(48px, 8vw, 96px);
}

.page-about *,
.page-about *::before,
.page-about *::after {
  box-sizing: border-box;
}

.page-about img {
  max-width: 100%;
  height: auto;
  display: block;
}

.page-about a:focus-visible,
.page-about summary:focus-visible {
  outline: 2px solid var(--c-lime);
  outline-offset: 3px;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  isolation: isolate;
  display: flex;
  align-items: flex-end;
  min-height: clamp(440px, 66vh, 640px);
  padding: clamp(36px, 8vw, 96px) var(--pad-x) clamp(76px, 11vw, 132px);
  overflow: hidden;
  clip-path: polygon(0 0, 100% 0, 100% 100%, 0 calc(100% - 46px));
}

.page-about .ab-hero__img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: -2;
  opacity: 0.72;
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(115% 85% at 84% 10%, rgba(200, 255, 61, 0.16), transparent 58%),
    linear-gradient(96deg, rgba(6, 18, 14, 0.97) 6%, rgba(6, 18, 14, 0.82) 46%, rgba(6, 18, 14, 0.38) 100%);
}

.page-about .ab-hero__inner {
  position: relative;
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
}

.page-about .ab-hero__crumb {
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--c-muted);
  margin-bottom: clamp(18px, 3vw, 30px);
}

.page-about .ab-hero__crumb a {
  color: var(--c-muted);
  text-decoration: none;
}

.page-about .ab-hero__crumb a:hover {
  color: var(--c-lime);
}

.page-about .ab-hero__crumb .breadcrumb__sep {
  margin: 0 8px;
  color: var(--c-line-soft);
}

.page-about .ab-hero__eyebrow {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 0 0 16px;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--c-lime);
}

.page-about .ab-hero__eyebrow::before {
  content: "";
  display: block;
  width: 52px;
  height: 2px;
  background: var(--c-lime);
}

.page-about .ab-hero__title {
  margin: 0 0 clamp(16px, 2.4vw, 22px);
  max-width: 20em;
  font-family: var(--f-display);
  font-weight: 800;
  font-size: clamp(34px, 6.2vw, 72px);
  line-height: 1.06;
  letter-spacing: -0.02em;
  color: var(--c-white);
}

.page-about .ab-hero__lede {
  margin: 0;
  max-width: 60ch;
  font-size: clamp(15px, 1.6vw, 17px);
  color: var(--c-body);
}

.page-about .ab-hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(18px, 4vw, 48px);
  list-style: none;
  margin: clamp(24px, 4vw, 40px) 0 0;
  padding: clamp(16px, 2.4vw, 22px) 0 0;
  border-top: 1px solid rgba(200, 255, 61, 0.3);
}

.page-about .ab-hero__meta li {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.page-about .ab-hero__meta .mono {
  font-size: clamp(20px, 2.6vw, 28px);
  font-weight: 600;
  color: var(--c-lime);
  line-height: 1.1;
}

.page-about .ab-hero__k {
  font-size: 12.5px;
  color: var(--c-muted);
}

/* ---------- 长阅读栅格 ---------- */
.page-about .ab-layout {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(24px, 5vw, 52px) var(--pad-x) 0;
  display: grid;
  gap: clamp(24px, 4vw, 56px);
}

.page-about .ab-toc__label {
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--c-muted);
}

.page-about .ab-toc__list {
  display: flex;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0 0 6px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .ab-toc__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  white-space: nowrap;
  padding: 8px 12px;
  font-size: 13px;
  color: var(--c-muted);
  text-decoration: none;
  background: var(--c-stand);
  border: 1px solid var(--c-line);
}

.page-about .ab-toc__link .mono {
  font-size: 11px;
  color: var(--c-line-soft);
  letter-spacing: 0.06em;
}

.page-about .ab-toc__link:hover {
  color: var(--c-lime);
  border-color: var(--c-lime-dim);
}

.page-about .ab-toc__link[aria-current] {
  color: var(--c-lime);
  border-color: var(--c-lime);
}

.page-about .ab-toc__link[aria-current] .mono {
  color: var(--c-lime);
}

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

/* ---------- 章节 ---------- */
.page-about .ab-sec {
  padding-block: clamp(26px, 4vw, 40px);
}

.page-about .ab-sec + .ab-sec {
  border-top: 1px solid var(--c-line);
}

.page-about .ab-sec__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 14px;
  margin-bottom: clamp(14px, 2.2vw, 20px);
}

.page-about .ab-sec__tag {
  margin-left: auto;
}

.page-about .ab-p {
  margin: 0 0 16px;
  max-width: 68ch;
  font-size: 16px;
}

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

.page-about .ab-figcap {
  display: block;
  margin-top: 10px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--c-muted);
}

/* ---------- 条线堆叠图 ---------- */
.page-about .ab-chart {
  margin: clamp(20px, 3vw, 30px) 0;
  padding: clamp(16px, 2.6vw, 22px);
  background: var(--c-stand);
  border: 1px solid var(--c-line);
}

.page-about .ab-bar {
  display: flex;
  height: 26px;
  background: var(--c-panel);
  border: 1px solid var(--c-line);
}

.page-about .ab-bar__seg {
  display: block;
  height: 100%;
  border-right: 2px solid var(--c-ink);
}

.page-about .ab-bar__seg:last-child {
  border-right: 0;
}

.page-about .ab-bar__seg--a { width: 38%; background: var(--c-lime); }
.page-about .ab-bar__seg--b { width: 29%; background: var(--c-lime-dim); }
.page-about .ab-bar__seg--c { width: 19%; background: var(--ab-lime-50); }
.page-about .ab-bar__seg--d { width: 14%; background: var(--ab-lime-26); }

.page-about .ab-legend {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px 16px;
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
}

.page-about .ab-legend__item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13.5px;
}

.page-about .ab-legend__dot {
  width: 9px;
  height: 9px;
  flex: 0 0 auto;
  border-radius: 50%;
}

.page-about .ab-legend__dot--a { background: var(--c-lime); }
.page-about .ab-legend__dot--b { background: var(--c-lime-dim); }
.page-about .ab-legend__dot--c { background: var(--ab-lime-50); }
.page-about .ab-legend__dot--d { background: var(--ab-lime-26); }

.page-about .ab-legend__name {
  color: var(--c-body);
}

.page-about .ab-legend__n {
  margin-left: auto;
  font-size: 12px;
  color: var(--c-muted);
}

/* ---------- 技术与数据行 ---------- */
.page-about .ab-rows {
  margin: clamp(20px, 3vw, 28px) 0;
  background: var(--c-panel);
  border: 1px solid var(--c-line);
}

.page-about .ab-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 4px;
  padding: 16px clamp(14px, 2.4vw, 22px);
}

.page-about .ab-row + .ab-row {
  border-top: 1px solid var(--c-line);
}

.page-about .ab-row__k {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--c-lime);
}

.page-about .ab-row__v {
  margin: 0;
  font-size: 14.5px;
  color: var(--c-body);
}

/* ---------- 版本刻度 ---------- */
.page-about .ab-railsec {
  position: relative;
  overflow: hidden;
  margin-block: clamp(20px, 3vw, 32px);
  padding: clamp(20px, 3.4vw, 36px);
  background: var(--c-stand);
  border: 1px solid var(--c-line);
}

.page-about .ab-railsec__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.24;
  pointer-events: none;
}

.page-about .ab-railsec > * {
  position: relative;
  z-index: 1;
}

.page-about .ab-rail {
  position: relative;
  margin-top: clamp(22px, 3.4vw, 34px);
}

.page-about .ab-rail::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 5px;
  height: 1px;
  background: linear-gradient(90deg, var(--c-lime), var(--c-line-soft) 72%, transparent);
}

.page-about .ab-rail__list {
  display: flex;
  gap: clamp(12px, 2vw, 20px);
  list-style: none;
  margin: 0;
  padding: 0 0 10px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .ab-node {
  position: relative;
  flex: 0 0 min(74vw, 258px);
  padding-top: 26px;
  min-width: 0;
}

.page-about .ab-node__dot {
  position: absolute;
  top: 0;
  left: 0;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--c-orange);
  box-shadow: 0 0 0 3px var(--ab-orange-18);
}

.page-about .ab-node--now .ab-node__dot {
  background: var(--c-lime);
  box-shadow: 0 0 0 3px rgba(200, 255, 61, 0.2);
}

.page-about .ab-node__det {
  border-top: 1px solid transparent;
}

.page-about .ab-node__sum {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 8px 10px;
  cursor: pointer;
  list-style: none;
  border: 1px solid var(--c-line);
  background: rgba(6, 18, 14, 0.6);
}

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

.page-about .ab-node__sum::after {
  content: "+";
  margin-left: auto;
  font-family: var(--f-mono);
  font-size: 14px;
  color: var(--c-lime);
}

.page-about .ab-node__det[open] .ab-node__sum::after {
  content: "–";
}

.page-about .ab-node__sum:hover {
  border-color: var(--c-lime-dim);
}

.page-about .ab-node__ver {
  font-size: 15px;
  font-weight: 600;
  color: var(--c-white);
}

.page-about .ab-node--now .ab-node__ver {
  color: var(--c-lime);
}

.page-about .ab-node__name {
  font-size: 13.5px;
  color: var(--c-body);
}

.page-about .ab-node__p {
  margin: 10px 0 0;
  padding-left: 10px;
  border-left: 2px solid var(--c-line-soft);
  font-size: 13.5px;
  color: var(--c-muted);
}

/* ---------- 窄段注释 ---------- */
.page-about .ab-note {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px 18px;
  margin: clamp(18px, 3vw, 28px) 0;
  padding: 14px 18px;
  background: var(--c-stand);
  border-left: 2px solid var(--c-lime);
}

.page-about .ab-note__text {
  margin: 0;
  max-width: 58ch;
  font-size: 14px;
  color: var(--c-body);
}

.page-about .ab-note__link {
  font-size: 13px;
  color: var(--c-lime);
  text-decoration: none;
  border-bottom: 1px solid rgba(200, 255, 61, 0.45);
  white-space: nowrap;
}

.page-about .ab-note__link:hover {
  border-bottom-color: var(--c-lime);
}

/* ---------- 生产工序 ---------- */
.page-about .ab-flow {
  display: grid;
  gap: clamp(20px, 3vw, 34px);
  margin-bottom: clamp(18px, 3vw, 26px);
}

.page-about .ab-step {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 12px;
  padding: 16px 0;
  border-top: 1px solid var(--c-line);
}

.page-about .ab-step__n {
  font-size: 22px;
  font-weight: 600;
  line-height: 1.2;
  color: var(--c-lime);
}

.page-about .ab-step__h {
  margin: 0 0 4px;
  font-family: var(--f-display);
  font-size: 18px;
  font-weight: 700;
  color: var(--c-white);
}

.page-about .ab-step__p {
  margin: 0;
  font-size: 14.5px;
  color: var(--c-body);
}

.page-about .ab-figure {
  margin: 0;
  border: 1px solid var(--c-line);
  background: var(--c-panel);
  padding: 10px;
}

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

.page-about .ab-figure .media__cap {
  font-family: var(--f-mono);
  font-size: 11.5px;
  letter-spacing: 0.03em;
  color: var(--c-muted);
  padding: 8px 2px 2px;
}

/* ---------- 三条坚持 ---------- */
.page-about .ab-creed {
  display: grid;
  gap: 16px;
  margin-top: clamp(14px, 2.4vw, 22px);
}

.page-about .ab-creed__item {
  padding: 4px 0 4px 16px;
  border-left: 2px solid var(--c-lime);
}

.page-about .ab-creed__h {
  margin: 0 0 6px;
  font-family: var(--f-display);
  font-size: 19px;
  font-weight: 700;
  color: var(--c-white);
}

.page-about .ab-creed__p {
  margin: 0;
  font-size: 14px;
  color: var(--c-muted);
}

/* ---------- 结尾入口 ---------- */
.page-about .ab-cta {
  margin-top: clamp(32px, 5vw, 56px);
  padding: clamp(22px, 3.6vw, 38px);
  background: var(--c-panel);
  border: 1px solid var(--c-line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 24px), calc(100% - 24px) 100%, 0 100%);
}

.page-about .ab-cta__title {
  margin: 0 0 10px;
  font-family: var(--f-display);
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--c-white);
}

.page-about .ab-cta__p {
  margin: 0;
  max-width: 58ch;
  font-size: 14.5px;
  color: var(--c-muted);
}

.page-about .ab-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 20px;
}

/* ---------- 平板与桌面 ---------- */
@media (min-width: 700px) {
  .page-about .ab-legend {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .ab-row {
    grid-template-columns: 88px minmax(0, 1fr);
    gap: 16px;
    align-items: baseline;
  }

  .page-about .ab-creed {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 20px;
  }
}

@media (min-width: 860px) {
  .page-about .ab-flow {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    align-items: start;
  }

  .page-about .ab-node {
    flex: 1 1 0;
    min-width: 0;
  }
}

@media (min-width: 960px) {
  .page-about .ab-layout {
    grid-template-columns: 232px minmax(0, 1fr);
    align-items: start;
  }

  .page-about .ab-toc {
    position: sticky;
    top: calc(var(--header-h) + 28px);
    align-self: start;
  }

  .page-about .ab-toc__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding: 0;
    border-left: 1px solid var(--c-line);
  }

  .page-about .ab-toc__link {
    display: flex;
    white-space: normal;
    border: 0;
    background: none;
    padding: 9px 14px;
    margin-left: -1px;
    border-left: 2px solid transparent;
    font-size: 13px;
    line-height: 1.5;
  }

  .page-about .ab-toc__link[aria-current] {
    border-left-color: var(--c-lime);
    background: linear-gradient(90deg, rgba(200, 255, 61, 0.1), transparent);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-toc__link,
  .page-about .ab-note__link,
  .page-about .ab-node__sum {
    transition: none;
  }
}