.page-about {
  --ab-index-w: 208px;
  position: relative;
  color: var(--paper);
  padding-block: clamp(18px, 3vw, 30px) clamp(60px, 9vw, 104px);
  background:
    radial-gradient(900px 520px at 88% -6%, rgba(77, 240, 208, 0.09), transparent 62%),
    radial-gradient(720px 440px at 0% 22%, rgba(90, 34, 48, 0.20), transparent 60%);
}

.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-bottom: clamp(22px, 3.4vw, 40px);
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--slate);
}

.page-about .breadcrumb a {
  color: var(--slate);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--line-cyan);
}

.page-about .breadcrumb [aria-current="page"] {
  color: var(--cyan-soft);
}

.page-about .breadcrumb__sep {
  color: rgba(140, 163, 173, 0.5);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  display: grid;
  gap: clamp(26px, 4vw, 52px);
}

.page-about .ab-hero__lead h1 {
  margin: 14px 0 20px;
  font-size: clamp(2rem, 4.6vw, 3.4rem);
  line-height: 1.14;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .lede {
  margin: 0;
  max-width: 46ch;
  font-size: clamp(1rem, 1.5vw, 1.0625rem);
  line-height: 1.85;
  color: rgba(232, 242, 238, 0.82);
}

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

.page-about .media-frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--ink-900);
}

.page-about .media-frame img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.72) contrast(1.05);
}

.page-about .media-frame--wide {
  aspect-ratio: 16 / 9;
}

.page-about figcaption {
  margin-top: 10px;
  font-size: var(--fs-12);
  line-height: 1.7;
  color: var(--slate);
}

/* ---------- 数字条 ---------- */
.page-about .ab-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin: clamp(32px, 5vw, 58px) 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.page-about .ab-stats li {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: clamp(15px, 2.4vw, 24px);
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .ab-stats__num {
  font-size: clamp(1.45rem, 3vw, 2.05rem);
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--cyan);
}

.page-about .ab-stats__label {
  font-size: var(--fs-12);
  line-height: 1.6;
  color: var(--slate);
}

/* ---------- 主栏与索引 ---------- */
.page-about .ab-body {
  display: grid;
  gap: clamp(26px, 4vw, 46px);
  margin-top: clamp(46px, 8vw, 94px);
}

.page-about .ab-index {
  padding-left: 16px;
  border-left: 2px solid var(--line-cyan);
}

.page-about .ab-index__title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--slate);
}

.page-about .ab-index__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-index__list a {
  display: flex;
  align-items: baseline;
  gap: 9px;
  padding: 6px 11px;
  font-size: var(--fs-14);
  color: var(--paper);
  text-decoration: none;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease),
    background var(--dur) var(--ease);
}

.page-about .ab-index__list a:hover,
.page-about .ab-index__list a:focus-visible {
  color: var(--cyan-soft);
  border-color: var(--line-cyan);
  background: rgba(77, 240, 208, 0.06);
}

.page-about .ab-index__no {
  font-size: var(--fs-12);
  color: var(--cyan);
}

.page-about .ab-index__note {
  display: none;
  margin: 18px 0 0;
  font-size: var(--fs-12);
  line-height: 1.7;
  color: var(--slate);
}

.page-about .ab-flow {
  display: flex;
  flex-direction: column;
  gap: clamp(44px, 7vw, 86px);
  min-width: 0;
}

/* ---------- 章节 ---------- */
.page-about .ab-sec {
  position: relative;
  min-width: 0;
  scroll-margin-top: 88px;
}

.page-about .ab-sec h2 {
  margin: 10px 0 18px;
  font-size: clamp(1.45rem, 2.9vw, 2.1rem);
  line-height: 1.26;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .ab-sec h3 {
  margin: 0 0 8px;
  font-size: var(--fs-20);
  line-height: 1.35;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .ab-prose p {
  max-width: 62ch;
  margin: 0 0 1.05em;
  font-size: var(--fs-16);
  line-height: 1.85;
  color: rgba(232, 242, 238, 0.84);
}

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

.page-about .ab-prose a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--line-cyan);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .ab-prose a:hover,
.page-about .ab-prose a:focus-visible {
  color: var(--cyan-soft);
  border-bottom-color: var(--cyan-soft);
}

.page-about .ab-prose--after {
  margin-top: clamp(20px, 3vw, 30px);
}

/* ---------- 时间线 ---------- */
.page-about .ab-timeline-art {
  margin-top: clamp(18px, 2.6vw, 28px);
}

.page-about .ab-tl {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: clamp(22px, 3.4vw, 34px);
  margin: clamp(24px, 4vw, 40px) 0 0;
  padding: 0 0 0 24px;
  list-style: none;
}

.page-about .ab-tl::before {
  content: "";
  position: absolute;
  top: 8px;
  bottom: 8px;
  left: 5px;
  width: 1px;
  background: linear-gradient(to bottom, var(--cyan), rgba(77, 240, 208, 0.06));
}

.page-about .ab-tl__item {
  position: relative;
}

.page-about .ab-tl__dot {
  position: absolute;
  top: 8px;
  left: -24px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--ink-950);
  border: 1px solid var(--cyan);
  box-shadow: 0 0 0 4px rgba(77, 240, 208, 0.10);
}

.page-about .ab-tl__item:nth-child(4) .ab-tl__dot {
  border-color: var(--ember);
  box-shadow: 0 0 0 4px rgba(255, 138, 61, 0.12);
}

.page-about .ab-tl__phase {
  display: inline-block;
  margin: 0 0 8px;
  padding: 2px 8px;
  font-size: var(--fs-12);
  letter-spacing: 0.12em;
  color: var(--amber);
  border: 1px solid rgba(255, 194, 138, 0.30);
  border-radius: var(--radius);
}

.page-about .ab-tl__item:nth-child(4) .ab-tl__phase {
  color: var(--ember);
  border-color: var(--line-ember);
}

.page-about .ab-tl__item p {
  max-width: 58ch;
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: rgba(232, 242, 238, 0.78);
}

/* ---------- 档案抽屉 ---------- */
.page-about .ab-drawers {
  display: grid;
  gap: 10px;
  margin-top: clamp(20px, 3.2vw, 32px);
}

.page-about .ab-drawer {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(11, 43, 36, 0.55);
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .ab-drawer[open] {
  border-color: var(--line-cyan);
  background: linear-gradient(180deg, rgba(18, 61, 50, 0.86), rgba(11, 43, 36, 0.66));
}

.page-about .ab-drawer summary {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 15px 18px;
  font-size: var(--fs-16);
  font-weight: 700;
  color: var(--paper);
  cursor: pointer;
  list-style: none;
  transition: color var(--dur) var(--ease);
}

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

.page-about .ab-drawer summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: var(--fs-20);
  line-height: 1;
  color: var(--cyan);
}

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

.page-about .ab-drawer summary:hover {
  color: var(--cyan-soft);
}

.page-about .ab-drawer summary:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: -2px;
}

.page-about .ab-drawer__no {
  font-size: var(--fs-12);
  color: var(--amber);
  letter-spacing: 0.08em;
}

.page-about .ab-drawer__body {
  padding: 0 18px 18px;
}

.page-about .ab-drawer__body p {
  margin: 0;
  max-width: 60ch;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: rgba(232, 242, 238, 0.8);
}

.page-about .ab-method-fig {
  margin: clamp(24px, 4vw, 38px) 0 0;
}

/* ---------- 团队 ---------- */
.page-about .ab-team {
  display: grid;
  gap: 12px;
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .ab-team__card {
  position: relative;
  padding: clamp(20px, 2.6vw, 28px);
  border-left: 2px solid var(--cyan);
  border-radius: var(--radius);
}

.page-about .ab-team__card:last-child {
  border-left-color: var(--ember);
}

.page-about .ab-team__num {
  margin: 0 0 6px;
  font-size: clamp(1.55rem, 3vw, 2.1rem);
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--cyan);
}

.page-about .ab-team__card p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: rgba(232, 242, 238, 0.78);
}

.page-about .ab-process {
  margin-top: clamp(24px, 3.6vw, 38px);
  padding-top: clamp(18px, 2.6vw, 26px);
  border-top: 1px solid var(--line);
}

.page-about .ab-process__steps {
  display: grid;
  gap: 14px;
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  counter-reset: ab-step;
}

.page-about .ab-process__steps li {
  position: relative;
  padding-left: 32px;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: rgba(232, 242, 238, 0.8);
}

.page-about .ab-process__steps li::before {
  counter-increment: ab-step;
  content: counter(ab-step, decimal-leading-zero);
  position: absolute;
  top: 3px;
  left: 0;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--amber);
}

/* ---------- 覆盖与共建 ---------- */
.page-about .ab-cover {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
  margin-top: clamp(20px, 3.2vw, 30px);
  padding: clamp(22px, 3.4vw, 36px);
  border-radius: var(--radius);
}

.page-about .ab-cover.panel--paper {
  background: var(--paper);
  color: var(--ink-950);
}

.page-about .ab-cover__list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 18px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-cover__list li {
  display: flex;
  flex-direction: column;
  gap: 3px;
  font-size: var(--fs-12);
  line-height: 1.6;
  color: rgba(6, 27, 23, 0.72);
}

.page-about .ab-cover__list .u-mono {
  font-size: clamp(1.35rem, 2.6vw, 1.85rem);
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--ink-800);
}

.page-about .ab-cover__text p {
  margin: 0 0 0.95em;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: rgba(6, 27, 23, 0.82);
}

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

/* ---------- 联系 ---------- */
.page-about .ab-contact {
  display: grid;
  gap: clamp(16px, 2.6vw, 26px);
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .ab-contact__card {
  padding: clamp(20px, 2.8vw, 30px);
  border-radius: var(--radius);
}

.page-about .ab-contact__card p {
  margin: 0 0 0.95em;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: rgba(232, 242, 238, 0.82);
}

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

.page-about .ab-contact__cta {
  padding: clamp(20px, 2.8vw, 30px);
  border: 1px dashed var(--line-ember);
  border-radius: var(--radius);
}

.page-about .ab-contact__cta h3 {
  margin-bottom: 10px;
}

.page-about .ab-contact__cta p {
  margin: 0 0 18px;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: rgba(232, 242, 238, 0.78);
}

.page-about .ab-contact__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 560px) {
  .page-about .ab-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 720px) {
  .page-about .ab-team {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .media-frame--wide {
    aspect-ratio: 21 / 9;
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    align-items: start;
  }

  .page-about .ab-hero__fig {
    margin-top: clamp(10px, 2vw, 28px);
  }

  .page-about .ab-cover {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
    align-items: start;
  }

  .page-about .ab-contact {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    align-items: start;
  }
}

@media (min-width: 960px) {
  .page-about .ab-body {
    grid-template-columns: var(--ab-index-w) minmax(0, 1fr);
    gap: clamp(36px, 5vw, 72px);
    align-items: start;
  }

  .page-about .ab-index {
    position: sticky;
    top: 28px;
    padding-left: 18px;
  }

  .page-about .ab-index__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 2px;
  }

  .page-about .ab-index__list a {
    padding: 8px 0;
    border: 0;
    border-bottom: 1px solid transparent;
    border-radius: 0;
  }

  .page-about .ab-index__list a:hover,
  .page-about .ab-index__list a:focus-visible {
    background: transparent;
    border-bottom-color: var(--line-cyan);
  }

  .page-about .ab-index__note {
    display: block;
  }
}
</