.page-about {
  --about-rule: 1px solid var(--grid-600);
  --about-gap: clamp(20px, 3vw, 40px);
  background:
    radial-gradient(110% 60% at 88% -12%, rgba(53, 240, 208, 0.10), transparent 62%),
    var(--ink-900);
  color: var(--paper-100);
}

.page-about h1,
.page-about h2,
.page-about h3,
.page-about p,
.page-about figure,
.page-about dl,
.page-about dd,
.page-about ol,
.page-about ul {
  margin: 0;
}

.page-about ol,
.page-about ul {
  padding: 0;
  list-style: none;
}

.page-about [id] {
  scroll-margin-top: 64px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero__inner {
  padding-block: clamp(18px, 3vw, 30px) clamp(26px, 4vw, 46px);
  border-bottom: var(--about-rule);
}

.page-about .about-hero__grid {
  display: grid;
  gap: var(--about-gap);
  margin-top: clamp(16px, 3vw, 30px);
}

.page-about .about-hero h1 {
  margin-top: 12px;
  font-family: var(--font-display);
  font-size: var(--fs-56);
  font-weight: 800;
  line-height: 1.02;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

.page-about .about-hero h1 em {
  font-style: normal;
  color: var(--signal-cyan);
}

.page-about .about-hero__lead {
  margin-top: 16px;
  max-width: 40em;
  font-size: var(--fs-18);
  line-height: 1.68;
}

.page-about .about-facts {
  border: var(--about-rule);
  background: var(--charcoal-800);
}

.page-about .about-facts__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px;
  padding: 12px 16px;
  border-bottom: 1px solid var(--grid-600);
}

.page-about .about-facts__row:last-child {
  border-bottom: 0;
}

.page-about .about-facts__key {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--slate-500);
}

.page-about .about-facts__val {
  font-family: var(--font-mono);
  font-size: var(--fs-18);
  font-weight: 700;
  color: var(--signal-cyan);
  font-variant-numeric: tabular-nums;
  text-align: right;
}

/* ---------- 章节导航条 ---------- */
.page-about .about-rail {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--teal-700);
  border-bottom: var(--about-rule);
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-rail__list {
  display: flex;
  align-items: stretch;
  gap: 0;
  min-width: max-content;
  padding-inline: clamp(8px, 2vw, 24px);
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 14px;
  border-bottom: 2px solid transparent;
  color: var(--paper-100);
  font-family: var(--font-mono);
  font-size: var(--fs-13);
  letter-spacing: 0.04em;
  text-decoration: none;
  white-space: nowrap;
  transition: background-color 200ms var(--ease), border-color 200ms var(--ease), color 200ms var(--ease);
}

.page-about .about-rail__link:hover {
  background-color: rgba(53, 240, 208, 0.12);
}

.page-about .about-rail__link:focus-visible {
  outline: 2px solid var(--focus-violet);
  outline-offset: -2px;
}

.page-about .about-rail__link.is-current {
  color: var(--signal-cyan);
  border-bottom-color: var(--focus-violet);
  background-color: rgba(53, 240, 208, 0.10);
}

.page-about .about-rail__num {
  color: var(--signal-orange);
  font-weight: 700;
}

/* ---------- 章节骨架 ---------- */
.page-about .about-section {
  border-bottom: var(--about-rule);
}

.page-about .about-section--last {
  border-bottom: 0;
}

.page-about .about-section__inner {
  padding-block: clamp(30px, 5vw, 62px);
}

.page-about .about-section .section-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  flex-wrap: wrap;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--grid-600);
}

.page-about .about-section .section-head__num {
  font-family: var(--font-mono);
  font-size: var(--fs-22);
  font-weight: 700;
  color: var(--signal-orange);
  font-variant-numeric: tabular-nums;
}

.page-about .about-section .section-head__title {
  font-family: var(--font-display);
  font-size: var(--fs-28);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -0.01em;
  text-wrap: balance;
}

.page-about .about-section__lead {
  margin-top: 18px;
  max-width: 46em;
  font-size: var(--fs-16);
  line-height: 1.7;
  color: var(--paper-100);
}

.page-about .about-section__lead strong {
  color: var(--signal-cyan);
  font-weight: 700;
}

.page-about .about-cols {
  display: grid;
  gap: clamp(22px, 3.5vw, 44px);
  margin-top: 22px;
}

.page-about .about-prose p {
  margin-bottom: 1em;
  font-size: var(--fs-16);
  line-height: 1.72;
}

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

.page-about .about-prose strong {
  color: var(--signal-cyan);
  font-weight: 700;
}

.page-about .about-prose a {
  color: var(--signal-cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .about-prose a:focus-visible {
  outline: 2px solid var(--focus-violet);
  outline-offset: 2px;
}

/* ---------- 01 主张旁注 ---------- */
.page-about .belief-note {
  align-self: start;
  padding: 20px;
  border: var(--about-rule);
  border-left: 3px solid var(--signal-cyan);
  background: var(--charcoal-800);
}

.page-about .belief-note__quote {
  font-family: var(--font-display);
  font-size: var(--fs-22);
  font-weight: 800;
  line-height: 1.28;
  color: var(--paper-100);
}

.page-about .belief-note__text {
  margin-top: 12px;
  font-size: var(--fs-16);
  line-height: 1.68;
  color: var(--sand-400);
}

/* ---------- 02 团队 ---------- */
.page-about .team-grid {
  display: grid;
  gap: 1px;
  margin-top: 22px;
  border: 1px solid var(--grid-600);
  background: var(--grid-600);
}

.page-about .team-card {
  padding: 18px 16px 20px;
  background: var(--charcoal-800);
  transition: background-color 200ms var(--ease);
}

.page-about .team-card:hover,
.page-about .team-card:focus-within {
  background: var(--teal-700);
}

.page-about .team-card__num {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-28);
  font-weight: 700;
  line-height: 1;
  color: var(--signal-cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .team-card__unit {
  margin-left: 4px;
  font-size: var(--fs-12);
  color: var(--slate-500);
}

.page-about .team-card__role {
  margin-top: 10px;
  font-family: var(--font-display);
  font-size: var(--fs-18);
  font-weight: 800;
  letter-spacing: 0.02em;
}

.page-about .team-card__text {
  margin-top: 8px;
  font-size: var(--fs-16);
  line-height: 1.6;
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-self: start;
}

.page-about .about-figure--wide {
  margin-top: clamp(26px, 4vw, 44px);
}

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

.page-about .about-figure__note {
  font-size: var(--fs-13);
  font-weight: 700;
  line-height: 1.6;
  color: var(--slate-500);
}

/* ---------- 03 流程 ---------- */
.page-about .flow {
  display: grid;
  gap: 0;
  margin-top: 26px;
}

.page-about .flow__step {
  padding: 16px;
  border: 1px solid var(--grid-600);
  background: var(--charcoal-800);
  transition: border-color 200ms var(--ease), background-color 200ms var(--ease);
}

.page-about .flow__step:hover,
.page-about .flow__step:focus {
  border-color: var(--signal-cyan);
  background: var(--teal-700);
  outline: none;
}

.page-about .flow__step:focus-visible {
  outline: 2px solid var(--focus-violet);
  outline-offset: 2px;
}

.page-about .flow__num {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--fs-13);
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--ink-900);
  background: var(--sand-400);
  padding: 2px 7px;
}

.page-about .flow__title {
  margin-top: 12px;
  font-family: var(--font-display);
  font-size: var(--fs-18);
  font-weight: 800;
  letter-spacing: 0.02em;
}

.page-about .flow__text {
  margin-top: 8px;
  font-size: var(--fs-16);
  line-height: 1.62;
}

.page-about .flow__more {
  max-height: 0;
  overflow: hidden;
  margin-top: 0;
  font-size: var(--fs-16);
  line-height: 1.62;
  color: var(--signal-cyan);
  transition: max-height 200ms var(--ease), margin-top 200ms var(--ease);
}

.page-about .flow__step:hover .flow__more,
.page-about .flow__step:focus .flow__more,
.page-about .flow__step:focus-within .flow__more {
  max-height: 8em;
  margin-top: 10px;
}

.page-about .flow__link {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8px 0;
}

.page-about .flow__link svg {
  transform: rotate(90deg);
  width: 34px;
  height: auto;
}

/* ---------- 04 历程 ---------- */
.page-about .timeline {
  margin-top: 26px;
  padding-left: 22px;
  border-left: 1px solid var(--grid-600);
}

.page-about .timeline__item {
  position: relative;
  padding: 0 0 26px 20px;
}

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: -27px;
  top: 5px;
  width: 9px;
  height: 9px;
  background: var(--ink-900);
  border: 1px solid var(--signal-cyan);
}

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

.page-about .timeline__phase {
  display: inline-block;
  padding: 3px 8px;
  border: 1px solid var(--signal-cyan);
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--signal-cyan);
}

.page-about .timeline__title {
  margin-top: 10px;
  font-family: var(--font-display);
  font-size: var(--fs-22);
  font-weight: 800;
  line-height: 1.24;
}

.page-about .timeline__text {
  margin-top: 8px;
  max-width: 44em;
  font-size: var(--fs-16);
  line-height: 1.7;
}

/* ---------- 05 服务范围 ---------- */
.page-about .range-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 20px 0;
  border: 1px solid var(--grid-600);
  background: var(--grid-600);
}

.page-about .range-stats__item {
  padding: 14px 16px;
  background: var(--charcoal-800);
}

.page-about .range-stats__label {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--sand-400);
}

.page-about .range-stats__num {
  margin-top: 6px;
  font-family: var(--font-mono);
  font-size: var(--fs-22);
  font-weight: 700;
  color: var(--paper-100);
  font-variant-numeric: tabular-nums;
}

/* ---------- 06 合作 ---------- */
.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

.page-about .coop-card {
  align-self: start;
  padding: 20px;
  border: var(--about-rule);
  background: var(--charcoal-800);
}

.page-about .coop-card__title {
  font-family: var(--font-display);
  font-size: var(--fs-18);
  font-weight: 800;
  letter-spacing: 0.02em;
  color: var(--sand-400);
}

.page-about .coop-card__list {
  margin-top: 14px;
  display: grid;
  gap: 10px;
}

.page-about .coop-card__list li {
  padding-left: 16px;
  position: relative;
  font-size: var(--fs-16);
  line-height: 1.6;
}

.page-about .coop-card__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 7px;
  height: 7px;
  background: var(--signal-cyan);
}

/* ---------- 07 延伸入口 ---------- */
.page-about .next-links {
  display: grid;
  gap: 1px;
  margin-top: 22px;
  border: 1px solid var(--grid-600);
  background: var(--grid-600);
}

.page-about .next-links__item {
  display: block;
  padding: 18px 16px 20px;
  background: var(--charcoal-800);
  color: var(--paper-100);
  text-decoration: none;
  transition: background-color 200ms var(--ease), color 200ms var(--ease);
}

.page-about .next-links__item:hover,
.page-about .next-links__item:focus-visible {
  background: var(--teal-700);
  color: var(--signal-cyan);
}

.page-about .next-links__item:focus-visible {
  outline: 2px solid var(--focus-violet);
  outline-offset: -2px;
}

.page-about .next-links__num {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--signal-orange);
}

.page-about .next-links__title {
  display: block;
  margin-top: 8px;
  font-family: var(--font-display);
  font-size: var(--fs-22);
  font-weight: 800;
}

.page-about .next-links__text {
  display: block;
  margin-top: 8px;
  font-size: var(--fs-16);
  line-height: 1.6;
}

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

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

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    align-items: end;
  }

  .page-about .about-cols {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }

  .page-about .about-cols--wide-left {
    grid-template-columns: minmax(0, 1.18fr) minmax(0, 0.82fr);
  }

  .page-about .about-figure {
    position: sticky;
    top: 72px;
  }

  .page-about .about-figure--wide {
    position: static;
  }

  .page-about .flow {
    grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr) auto minmax(0, 1fr) auto minmax(0, 1fr);
    align-items: stretch;
  }

  .page-about .flow__link {
    padding: 0 6px;
  }

  .page-about .flow__link svg {
    transform: none;
    width: 40px;
  }

  .page-about .timeline {
    padding-left: 0;
    border-left: 0;
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1px;
    background: var(--grid-600);
    border: 1px solid var(--grid-600);
  }

  .page-about .timeline__item {
    padding: 22px 20px;
    background: var(--ink-900);
  }

  .page-about .timeline__item::before {
    display: none;
  }

  .page-about .timeline__item:last-child {
    padding-bottom: 22px;
  }
}

@media (min-width: 1100px) {
  .page-about .team-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 1280px) {
  .page-about .timeline {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__link,
  .page-about .team-card,
  .page-about .flow__step,
  .page-about .flow__more,
  .page-about .next-links__item {
    transition: none;
  }
}