.page-about {
  --ab-max: 1240px;
  --ab-radius: var(--radius-organic);
  background: var(--ink-950);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.78;
}

.page-about a {
  color: var(--cyan);
  text-decoration: none;
}

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

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(2rem, 7vw, 4.5rem) 0 clamp(2rem, 5vw, 3.5rem);
  border-bottom: 1px solid var(--line);
  background: var(--ink-950);
}

.page-about .ab-hero__glow {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.3;
  pointer-events: none;
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(6, 26, 22, 0.6) 0%, rgba(6, 26, 22, 0.88) 58%, var(--ink-950) 100%);
  pointer-events: none;
}

.page-about .ab-hero__inner {
  position: relative;
  z-index: 1;
  max-width: var(--ab-max);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.page-about .ab-hero .breadcrumb {
  margin-bottom: 1.5rem;
}

.page-about .ab-hero .eyebrow {
  margin: 0 0 0.85rem;
  color: var(--cyan);
}

.page-about .ab-hero h1 {
  margin: 0;
  max-width: 18em;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2rem, 6.2vw, 3.6rem);
  line-height: 1.14;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .ab-hero__lede {
  margin: 1.1rem 0 0;
  max-width: 40em;
  font-size: clamp(0.98rem, 2.4vw, 1.125rem);
  color: var(--mute);
}

.page-about .ab-stats {
  margin: clamp(1.6rem, 4vw, 2.4rem) 0 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--ab-radius);
  overflow: hidden;
}

.page-about .ab-stats__item {
  background: var(--ink-900);
  padding: 0.9rem 1rem;
}

.page-about .ab-stats dt {
  margin: 0;
  font-size: 0.76rem;
  letter-spacing: 0.06em;
  color: var(--mute);
}

.page-about .ab-stats dd {
  margin: 0.3rem 0 0;
  font-size: clamp(1.35rem, 4vw, 1.85rem);
  line-height: 1.1;
  color: var(--cyan-soft);
}

.page-about .ab-stats dd span {
  margin-left: 0.28rem;
  font-size: 0.72rem;
  color: var(--mute);
}

/* ---------- 主体两栏 ---------- */
.page-about .ab-body {
  max-width: var(--ab-max);
  margin: 0 auto;
  padding: clamp(2rem, 5vw, 3.5rem) var(--gutter) clamp(3rem, 7vw, 5rem);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.75rem, 4vw, 3rem);
}

.page-about .ab-index {
  border-left: 1px solid var(--line);
  padding-left: 1rem;
}

.page-about .ab-index__title {
  margin: 0 0 0.75rem;
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  color: var(--mute);
}

.page-about .ab-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.15rem;
}

.page-about .ab-index__list a {
  display: block;
  padding: 0.5rem 0.5rem 0.5rem 0.6rem;
  margin-left: -0.6rem;
  border-left: 2px solid transparent;
  color: var(--paper);
  font-size: 0.92rem;
  transition: color 0.22s var(--ease), border-color 0.22s var(--ease), background-color 0.22s var(--ease);
}

.page-about .ab-index__list a .mono {
  display: inline-block;
  min-width: 1.9em;
  color: var(--ember);
  font-size: 0.78rem;
}

.page-about .ab-index__list a:hover,
.page-about .ab-index__list a:focus-visible {
  color: var(--cyan-soft);
  border-left-color: var(--cyan);
  background: var(--ink-900);
  outline: none;
}

.page-about .ab-index__foot {
  margin: 1.1rem 0 0;
  font-size: 0.78rem;
  line-height: 1.65;
  color: var(--mute);
}

/* ---------- 章节 ---------- */
.page-about .ab-sec {
  padding-top: clamp(1.75rem, 4vw, 2.75rem);
  border-top: 1px solid var(--line);
}

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

.page-about .ab-sec + .ab-sec {
  margin-top: clamp(2rem, 5vw, 3.25rem);
}

.page-about .ab-sec__head {
  display: flex;
  align-items: baseline;
  gap: 0.8rem;
  margin-bottom: 1rem;
}

.page-about .ab-sec__num {
  flex: none;
  font-size: 0.95rem;
  letter-spacing: 0.1em;
  color: var(--ember);
}

.page-about .ab-sec h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.4rem, 4.4vw, 2rem);
  line-height: 1.28;
  letter-spacing: -0.015em;
  color: var(--paper);
}

.page-about .ab-prose p {
  margin: 0 0 0.95rem;
  color: rgba(242, 247, 241, 0.86);
}

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

.page-about .ab-sec h3 {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.06rem;
  line-height: 1.4;
  color: var(--cyan-soft);
}

.page-about .ab-note {
  margin-top: 1.3rem;
  padding: 0.95rem 1.1rem;
  background: var(--ink-900);
  border-left: 2px solid var(--cyan);
  border-radius: 2px 14px 2px 14px;
}

.page-about .ab-note__label {
  margin: 0 0 0.4rem;
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .ab-note p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--mute);
}

/* ---------- 图片 ---------- */
.page-about .ab-fig {
  margin: 1.4rem 0 1.5rem;
}

.page-about .ab-fig img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border: 1px solid var(--line);
  border-radius: var(--ab-radius);
  background: var(--ink-800);
}

.page-about .ab-fig figcaption {
  margin-top: 0.6rem;
  font-size: 0.8rem;
  color: var(--mute);
}

/* ---------- 内容线卡片 ---------- */
.page-about .ab-mapgrid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0.85rem;
}

.page-about .ab-mapcard {
  display: block;
  padding: 1rem 1.1rem 1.1rem;
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-radius: var(--radius-small);
  color: var(--paper);
  transition: border-color 0.24s var(--ease), background-color 0.24s var(--ease);
}

.page-about .ab-mapcard__no {
  margin: 0 0 0.45rem;
  font-size: 0.73rem;
  letter-spacing: 0.08em;
  color: var(--mute);
}

.page-about .ab-mapcard h3 {
  color: var(--paper);
  font-size: 1rem;
}

.page-about .ab-mapcard p:last-child {
  margin: 0.3rem 0 0;
  font-size: 0.88rem;
  color: var(--mute);
}

.page-about .ab-mapcard:hover,
.page-about .ab-mapcard:focus-visible {
  border-color: var(--cyan);
  background: var(--ink-700);
  outline: none;
}

.page-about .ab-mapcard:hover h3,
.page-about .ab-mapcard:focus-visible h3 {
  color: var(--cyan-soft);
}

/* ---------- 步骤 ---------- */
.page-about .ab-steps {
  list-style: none;
  margin: 1.2rem 0 0;
  padding: 0;
  counter-reset: abstep;
}

.page-about .ab-steps li {
  position: relative;
  padding: 0.9rem 0 0.9rem 3rem;
  border-bottom: 1px dashed var(--line);
}

.page-about .ab-steps li:first-child {
  border-top: 1px dashed var(--line);
}

.page-about .ab-steps li::before {
  counter-increment: abstep;
  content: counter(abstep, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 0.95rem;
  width: 2.1rem;
  height: 2.1rem;
  display: grid;
  place-items: center;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--ember);
  border: 1px solid var(--line);
  border-radius: 2px 10px 2px 10px;
}

.page-about .ab-steps p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--mute);
}

/* ---------- 团队角色 ---------- */
.page-about .ab-roles {
  margin-top: 1.3rem;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0.85rem;
}

.page-about .ab-role {
  padding: 1rem 1.1rem 1.1rem;
  background: var(--ink-900);
  border: 1px solid var(--line);
  border-radius: var(--ab-radius);
}

.page-about .ab-role p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--mute);
}

.page-about .ab-role__tag {
  margin-top: 0.7rem !important;
  font-size: 0.74rem !important;
  letter-spacing: 0.06em;
  color: var(--cyan) !important;
}

/* ---------- 时间线 ---------- */
.page-about .ab-timeline {
  list-style: none;
  margin: 1.4rem 0 0;
  padding: 0 0 0 1.3rem;
  position: relative;
}

.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 0.28rem;
  top: 0.5rem;
  bottom: 0.6rem;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan) 0%, var(--line) 62%, transparent 100%);
}

.page-about .ab-timeline__item {
  position: relative;
  padding-bottom: 1.5rem;
}

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

.page-about .ab-timeline__item::before {
  content: "";
  position: absolute;
  left: -1.19rem;
  top: 0.6rem;
  width: 0.55rem;
  height: 0.55rem;
  border-radius: 50%;
  background: var(--ink-950);
  border: 1.5px solid var(--cyan);
}

.page-about .ab-timeline__stage {
  margin: 0 0 0.2rem;
  font-size: 0.73rem;
  letter-spacing: 0.14em;
  color: var(--ember);
}

.page-about .ab-timeline__item > p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--mute);
}

.page-about .ab-timeline__note {
  margin-top: 0.6rem;
  border: 1px solid var(--line);
  border-radius: 2px 12px 2px 12px;
  background: var(--ink-900);
  padding: 0.55rem 0.85rem;
}

.page-about .ab-timeline__note summary {
  cursor: pointer;
  font-size: 0.82rem;
  color: var(--cyan);
  list-style: none;
}

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

.page-about .ab-timeline__note summary::after {
  content: " +";
  font-family: var(--font-mono);
}

.page-about .ab-timeline__note[open] summary::after {
  content: " −";
}

.page-about .ab-timeline__note p {
  margin: 0.5rem 0 0;
  font-size: 0.85rem;
  color: var(--mute);
}

/* ---------- 联系 ---------- */
.page-about .ab-contact {
  margin-top: 1.4rem;
  padding: 1.15rem 1.2rem 1.3rem;
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-radius: var(--ab-radius);
}

.page-about .ab-contact__label {
  margin: 0 0 0.6rem;
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .ab-contact ul {
  list-style: none;
  margin: 0 0 0.8rem;
  padding: 0;
  display: grid;
  gap: 0.35rem;
  font-size: 0.92rem;
  word-break: break-word;
}

.page-about .ab-contact li span {
  display: inline-block;
  min-width: 3.4em;
  margin-right: 0.5rem;
  font-size: 0.74rem;
  color: var(--mute);
}

.page-about .ab-contact__note {
  margin: 0 0 1rem;
  font-size: 0.85rem;
  color: var(--mute);
}

.page-about .ab-contact .btn {
  display: inline-block;
  padding: 0.6rem 1.15rem;
  font-size: 0.88rem;
  border-radius: var(--radius-small);
  border: 1px solid var(--cyan);
  color: var(--cyan);
  transition: background-color 0.22s var(--ease), color 0.22s var(--ease);
}

.page-about .ab-contact .btn:hover,
.page-about .ab-contact .btn:focus-visible {
  background: var(--cyan);
  color: var(--ink-950);
  outline: none;
}

/* ---------- 收尾 ---------- */
.page-about .ab-next {
  margin-top: clamp(2rem, 5vw, 3rem);
  padding: 1.25rem 1.2rem;
  background: var(--ink-900);
  border-top: 1px solid var(--line);
  border-radius: 3px 20px 3px 20px;
}

.page-about .ab-next__title {
  margin: 0 0 0.8rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--paper);
}

.page-about .ab-next__links {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0.5rem;
}

.page-about .ab-next__links a {
  display: block;
  padding: 0.6rem 0.9rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-small);
  color: var(--paper);
  font-size: 0.9rem;
  transition: border-color 0.22s var(--ease), color 0.22s var(--ease);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .ab-mapgrid,
  .page-about .ab-roles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .ab-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 960px) {
  .page-about .ab-body {
    grid-template-columns: 210px minmax(0, 1fr);
    gap: clamp(2rem, 4vw, 3.5rem);
    align-items: start;
  }

  .page-about .ab-index {
    position: sticky;
    top: 5.5rem;
  }

  .page-about .ab-fig--half {
    max-width: 34rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition: none !important;
  }
}