.page-about {
  --ab-rail-w: 208px;
  --ab-gap: clamp(1.25rem, 3.5vw, 3.5rem);
  --ab-line: rgba(159, 176, 191, 0.16);
  --ab-line-strong: rgba(159, 176, 191, 0.32);
  --ab-text: rgba(230, 234, 238, 0.86);
  --ab-dim: rgba(159, 176, 191, 0.74);
  background-color: var(--wb-ink-950);
  overflow-x: hidden;
}

/* ---------- 通用排版件 ---------- */
.page-about .ab-h2 {
  margin: 0 0 1rem;
  font-size: clamp(1.6rem, 1.1rem + 2.1vw, 2.5rem);
  line-height: 1.16;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--wb-paper-100);
}

.page-about .ab-p {
  margin: 0 0 1.05rem;
  font-size: var(--wb-fs-body);
  line-height: 1.78;
  color: var(--ab-text);
  max-width: 62ch;
}

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

.page-about .ab-cap {
  margin-top: 0.7rem;
  font-family: var(--wb-font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  line-height: 1.6;
  color: var(--ab-dim);
}

.page-about .ab-code {
  font-family: var(--wb-font-mono);
  font-size: 0.94em;
  font-weight: 700;
  color: var(--wb-gold-200);
  letter-spacing: 0.01em;
}

.page-about .ab-figure {
  margin: 1.9rem 0 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-color: var(--wb-ink-800);
}

.page-about .ab-note {
  margin: 1.5rem 0 0;
}

.page-about .ab-note p {
  margin: 0;
  font-size: 0.96rem;
  line-height: 1.7;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  padding-block: clamp(1.75rem, 4vw, 3.5rem) clamp(2rem, 4vw, 3.5rem);
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(159, 176, 191, 0.055) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(159, 176, 191, 0.055) 1px, transparent 1px);
  background-size: 72px 72px;
  pointer-events: none;
  z-index: 0;
}

.page-about .ab-hero__inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(2rem, 4vw, 3.5rem);
  align-items: start;
}

.page-about .ab-hero__eyebrow {
  margin: 1.5rem 0 0.7rem;
  font-family: var(--wb-font-mono);
  font-size: 12px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--wb-gold-500);
}

.page-about .ab-hero__title {
  margin: 0;
  font-size: clamp(2.9rem, 1.6rem + 7vw, 6rem);
  line-height: 0.94;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--wb-white);
}

.page-about .ab-hero__lead {
  margin: 1.5rem 0 0;
  max-width: 40ch;
  font-size: clamp(1rem, 0.94rem + 0.3vw, 1.12rem);
  line-height: 1.78;
  color: var(--ab-text);
}

.page-about .ab-hero__stats {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem clamp(1.5rem, 4vw, 3rem);
  margin: 2rem 0 0;
  padding: 1.15rem 0 0;
  list-style: none;
  border-top: 1px solid var(--ab-line);
}

.page-about .ab-hero__stat {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.page-about .ab-hero__num {
  font-family: var(--wb-font-mono);
  font-size: clamp(1.4rem, 1.1rem + 1.2vw, 1.9rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1;
  color: var(--wb-gold-500);
}

.page-about .ab-hero__cap {
  font-size: 12px;
  letter-spacing: 0.09em;
  color: var(--ab-dim);
}

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

.page-about .ab-hero__figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--ab-line-strong);
  background-color: var(--wb-ink-800);
}

/* ---------- 章节骨架 ---------- */
.page-about .ab-chapter {
  padding-block: clamp(2.25rem, 5vw, 4.5rem);
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-chapter__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.1rem;
}

.page-about .ab-rail {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
}

.page-about .ab-rail__num {
  font-family: var(--wb-font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--wb-gold-500);
}

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

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

/* ---------- 团队三组 ---------- */
.page-about .ab-team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.4rem;
  margin: 1.5rem 0 0;
}

.page-about .ab-team__item {
  position: relative;
  padding-left: 1.05rem;
}

.page-about .ab-team__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.15rem;
  bottom: 0.15rem;
  width: 3px;
  background-color: var(--wb-ink-600);
  transition: width 120ms var(--wb-ease), background-color 120ms var(--wb-ease);
}

.page-about .ab-team__item:hover::before {
  width: 6px;
  background-color: var(--wb-gold-500);
}

.page-about .ab-team__k {
  margin: 0 0 0.5rem;
  font-family: var(--wb-font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--wb-gold-200);
}

.page-about .ab-team__d {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.76;
  color: var(--ab-text);
}

/* ---------- 发展阶段时间轴 ---------- */
.page-about .ab-timeline {
  margin: 1.6rem 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--ab-line);
}

.page-about .ab-timeline__item {
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-stage__head {
  display: flex;
  align-items: baseline;
  gap: 0.85rem;
  padding: 0.95rem 0;
  cursor: pointer;
  list-style: none;
}

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

.page-about .ab-stage__head:focus-visible {
  outline: 2px solid var(--wb-gold-500);
  outline-offset: 2px;
}

.page-about .ab-stage__num {
  flex: 0 0 auto;
  min-width: 3.6rem;
  font-family: var(--wb-font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--wb-gold-500);
}

.page-about .ab-stage__name {
  flex: 1 1 auto;
  min-width: 0;
  font-size: clamp(1rem, 0.95rem + 0.3vw, 1.12rem);
  font-weight: 600;
  color: var(--wb-paper-100);
  transition: color 120ms var(--wb-ease);
}

.page-about .ab-stage__head:hover .ab-stage__name {
  color: var(--wb-gold-200);
}

.page-about .ab-stage__toggle {
  flex: 0 0 auto;
  font-family: var(--wb-font-mono);
  font-size: 14px;
  line-height: 1;
  color: var(--ab-dim);
}

.page-about .ab-stage__toggle::before {
  content: "+";
}

.page-about .ab-stage[open] .ab-stage__toggle::before {
  content: "\2212";
  color: var(--wb-gold-500);
}

.page-about .ab-stage__body {
  padding: 0 0 1.15rem;
}

.page-about .ab-stage__body p {
  margin: 0;
  max-width: 60ch;
  font-size: 0.95rem;
  line-height: 1.78;
  color: var(--ab-text);
}

/* ---------- 协作流程 ---------- */
.page-about .ab-flow {
  margin: 1.4rem 0 1.5rem;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
}

.page-about .ab-flow__step {
  display: grid;
  grid-template-columns: 2.6rem minmax(0, 1fr);
  gap: 0.9rem;
  align-items: baseline;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-flow__step:first-child {
  border-top: 1px solid var(--ab-line);
}

.page-about .ab-flow__num {
  font-family: var(--wb-font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--wb-slate-300);
}

.page-about .ab-flow__text {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.72;
  color: var(--ab-text);
}

/* ---------- 结语 ---------- */
.page-about .ab-closing {
  padding-block: clamp(2.75rem, 6vw, 5.5rem);
}

.page-about .ab-closing__inner {
  position: relative;
  padding-top: clamp(1.5rem, 3vw, 2.25rem);
}

.page-about .ab-closing__inner::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: clamp(3rem, 8vw, 7rem);
  height: 2px;
  background-color: var(--wb-gold-500);
}

.page-about .ab-closing__k {
  margin: 0 0 0.9rem;
  font-family: var(--wb-font-mono);
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--ab-dim);
}

.page-about .ab-closing__text {
  margin: 0;
  max-width: 34ch;
  font-size: clamp(1.35rem, 0.95rem + 1.7vw, 2.15rem);
  line-height: 1.5;
  font-weight: 700;
  letter-spacing: -0.012em;
  color: var(--wb-paper-100);
}

.page-about .ab-closing__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: clamp(1.5rem, 3vw, 2.25rem);
}

/* ---------- 响应式 ---------- */
@media (min-width: 760px) {
  .page-about .ab-team {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.75rem;
  }
}

@media (min-width: 900px) {
  .page-about .ab-chapter__inner {
    grid-template-columns: var(--ab-rail-w) minmax(0, 1fr);
    gap: var(--ab-gap);
  }

  .page-about .ab-rail {
    position: sticky;
    top: 6.5rem;
    flex-direction: column;
    align-items: flex-start;
    gap: 0.45rem;
  }

  .page-about .ab-rail__num {
    font-size: 13px;
  }

  .page-about .ab-hero__inner {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    gap: clamp(2.25rem, 5vw, 4.5rem);
    align-items: center;
  }
}

@media (min-width: 1100px) {
  .page-about .ab-chapter--brief .ab-body {
    max-width: 64ch;
  }

  .page-about .ab-closing__text {
    max-width: 30ch;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-team__item::before,
  .page-about .ab-stage__name {
    transition: none;
  }
}