.page-about {
  background:
    linear-gradient(var(--grid-faint) 1px, transparent 1px) 0 0 / 100% 96px,
    var(--ink);
  color: var(--paper);
  padding-bottom: clamp(56px, 8vw, 104px);
}

.page-about .breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  padding-block: clamp(14px, 2vw, 22px);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--steel);
}

.page-about .breadcrumb a {
  color: var(--paper-2);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

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

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

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: clamp(22px, 3.4vw, 40px);
  padding-bottom: clamp(28px, 4vw, 52px);
  border-bottom: 1px solid var(--grid);
}

.page-about .about-hero .eyebrow {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--signal);
  text-transform: uppercase;
}

.page-about .about-hero h1 {
  margin: 0;
  font-size: clamp(30px, 6vw, 60px);
  line-height: 1.12;
  letter-spacing: -0.02em;
  font-weight: 900;
  color: var(--paper);
}

.page-about .about-hero .lede {
  margin: 18px 0 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.65;
  color: var(--paper-2);
}

.page-about .about-hero-strip {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(20px, 3vw, 32px);
  background: var(--grid);
  border: 1px solid var(--grid);
}

.page-about .about-hero-strip .stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 12px;
  background: var(--ink-2);
}

.page-about .about-hero-strip .stat-value {
  font-family: var(--font-mono);
  font-size: clamp(22px, 3.4vw, 34px);
  font-weight: 700;
  line-height: 1;
  color: var(--gold);
}

.page-about .about-hero-strip .stat-label {
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--steel);
}

/* ---------- 图片容器 ---------- */
.page-about .about-figure {
  margin: 0;
  border: 1px solid var(--grid);
  background: var(--ink-2);
  overflow: hidden;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.78) contrast(1.06);
}

.page-about .about-hero-figure {
  position: relative;
  clip-path: polygon(0 0, 100% 0, 100% 100%, 8% 100%);
}

.page-about .about-figure .media-caption {
  display: block;
  padding: 10px 14px;
  border-top: 1px solid var(--grid);
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1.5;
  color: var(--steel);
  background: var(--ink-2);
}

/* ---------- 章节目录 ---------- */
.page-about .about-toc {
  display: flex;
  gap: 1px;
  margin-block: clamp(18px, 2.4vw, 28px);
  border: 1px solid var(--grid);
  background: var(--grid);
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-toc a {
  flex: 0 0 auto;
  padding: 11px 16px;
  background: var(--ink);
  color: var(--paper-2);
  font-size: 13px;
  text-decoration: none;
  white-space: nowrap;
  transition: background 160ms ease, color 160ms ease;
}

.page-about .about-toc a b {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--signal);
  margin-right: 8px;
}

.page-about .about-toc a:hover,
.page-about .about-toc a:focus-visible {
  background: var(--ink-2);
  color: var(--cyan);
}

/* ---------- 章节通用 ---------- */
.page-about .about-sec {
  padding-block: clamp(34px, 5vw, 64px);
  border-top: 1px solid var(--grid);
}

.page-about .section-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: clamp(16px, 2.4vw, 26px);
}

.page-about .section-head .num {
  font-family: var(--font-mono);
  font-size: clamp(30px, 5vw, 52px);
  font-weight: 700;
  line-height: 1;
  color: var(--signal);
}

.page-about .section-title {
  margin: 0;
  font-size: clamp(22px, 3.4vw, 36px);
  font-weight: 900;
  letter-spacing: -0.01em;
  line-height: 1.2;
  color: var(--paper);
}

.page-about .about-sec-lede {
  margin: 0 0 clamp(18px, 2.6vw, 28px);
  max-width: 68ch;
  font-size: 15px;
  line-height: 1.65;
  color: var(--paper-2);
}

.page-about .split-grid {
  display: grid;
  gap: clamp(18px, 2.6vw, 30px);
}

/* ---------- 01 起点 ---------- */
.page-about .about-panel {
  background: var(--paper);
  color: var(--brown);
  padding: clamp(20px, 3vw, 34px);
  border-left: 3px solid var(--gold);
}

.page-about .about-panel p {
  margin: 0 0 14px;
  font-size: 15.5px;
  line-height: 1.68;
}

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

.page-about .about-audience-panel {
  border: 1px solid var(--grid);
  background: var(--ink-2);
  padding: clamp(18px, 2.6vw, 28px);
}

.page-about .about-audience-panel h3 {
  margin: 0 0 14px;
  font-size: 15px;
  letter-spacing: 0.04em;
  color: var(--cyan);
}

.page-about .about-audience {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 12px;
}

.page-about .about-audience li {
  position: relative;
  padding-left: 16px;
  font-size: 14px;
  line-height: 1.62;
  color: var(--paper-2);
  border-left: 1px solid var(--grid);
  transition: border-color 160ms ease;
}

.page-about .about-audience li strong {
  display: block;
  color: var(--paper);
  font-size: 14.5px;
  margin-bottom: 3px;
}

.page-about .about-audience li:hover {
  border-left-color: var(--cyan);
}

/* ---------- 02 内容体系 ---------- */
.page-about .about-board {
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
  margin-bottom: clamp(26px, 4vw, 44px);
}

.page-about .about-board-item {
  background: var(--ink-2);
  padding: clamp(16px, 2.4vw, 24px);
  transition: background 160ms ease, box-shadow 160ms ease;
}

.page-about .about-board-item:hover {
  background: var(--ink-3);
  box-shadow: inset 3px 0 0 var(--cyan);
}

.page-about .about-board-tag {
  display: inline-block;
  margin-bottom: 10px;
  padding: 2px 8px;
  border: 1px solid var(--steel);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.12em;
  color: var(--steel);
}

.page-about .about-board-item h3 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 800;
  color: var(--gold);
}

.page-about .about-board-item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.62;
  color: var(--paper-2);
}

.page-about .about-flow-title {
  margin: 0 0 14px;
  font-size: 15px;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .about-flow {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

.page-about .flow-step {
  display: grid;
  grid-template-columns: 46px 1fr;
  gap: 12px;
  padding: 14px;
  background: var(--ink);
  transition: background 160ms ease, box-shadow 160ms ease;
}

.page-about .flow-step:hover,
.page-about .flow-step:focus-within {
  background: var(--ink-2);
  box-shadow: inset 2px 0 0 var(--gold);
}

.page-about .flow-idx {
  font-family: var(--font-mono);
  font-size: 18px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--steel);
}

.page-about .flow-step:hover .flow-idx {
  color: var(--gold);
}

.page-about .flow-body h4 {
  margin: 0 0 5px;
  font-size: 15px;
  font-weight: 800;
  color: var(--paper);
}

.page-about .flow-body p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--paper-2);
}

.page-about .about-system-figure {
  margin-top: clamp(22px, 3vw, 34px);
}

/* ---------- 03 双端演进 ---------- */
.page-about .about-phases {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0 0 clamp(18px, 2.6vw, 26px);
  padding: 0;
  list-style: none;
  background: var(--grid);
  border: 1px solid var(--grid);
}

.page-about .about-phases a {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 14px 12px;
  background: var(--ink-2);
  text-decoration: none;
  transition: background 160ms ease, box-shadow 160ms ease;
}

.page-about .about-phases a:hover,
.page-about .about-phases a:focus-visible {
  background: var(--ink-3);
  box-shadow: inset 0 -2px 0 var(--cyan);
}

.page-about .phase-num {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 700;
  line-height: 1;
  color: var(--gold);
}

.page-about .phase-name {
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--paper-2);
}

.page-about .about-phase-cards {
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

.page-about .phase-card {
  background: var(--ink-2);
  padding: clamp(16px, 2.4vw, 24px);
  border-left: 2px solid transparent;
  transition: background 180ms ease, border-color 180ms ease;
}

.page-about .phase-card:target {
  background: var(--ink-3);
  border-left-color: var(--cyan);
}

.page-about .phase-card-num {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--signal);
  margin-bottom: 8px;
}

.page-about .phase-card h3 {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 800;
  color: var(--paper);
}

.page-about .phase-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.62;
  color: var(--paper-2);
}

/* ---------- 04 资料标准 ---------- */
.page-about .about-data-body p {
  margin: 0 0 16px;
  font-size: 15px;
  line-height: 1.65;
  color: var(--paper-2);
}

.page-about .about-archive {
  margin: 0 0 16px;
  border-top: 1px solid var(--grid);
}

.page-about .archive-row {
  display: grid;
  grid-template-columns: 5.5em 1fr;
  gap: 10px;
  padding: 11px 0;
  border-bottom: 1px solid var(--grid);
}

.page-about .archive-row dt {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--cyan);
}

.page-about .archive-row dd {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--paper-2);
}

/* ---------- 05 团队 ---------- */
.page-about .about-metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
  margin-bottom: clamp(22px, 3vw, 34px);
}

.page-about .metric {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: clamp(14px, 2.2vw, 22px);
  background: var(--ink-2);
}

.page-about .metric b {
  font-family: var(--font-mono);
  font-size: clamp(26px, 4vw, 40px);
  font-weight: 700;
  line-height: 1;
  color: var(--gold);
  animation: about-lit 700ms ease-out both;
}

.page-about .metric span {
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--steel);
}

@keyframes about-lit {
  from { opacity: 0.35; }
  to { opacity: 1; }
}

.page-about .about-roles {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

.page-about .about-roles li {
  padding: 14px 16px;
  background: var(--ink-2);
  font-size: 14px;
  line-height: 1.62;
  color: var(--paper-2);
  transition: background 160ms ease;
}

.page-about .about-roles li:hover {
  background: var(--ink-3);
}

.page-about .about-roles strong {
  color: var(--paper);
  margin-right: 6px;
}

.page-about .about-collab {
  border: 1px solid var(--grid);
  border-left: 3px solid var(--signal);
  padding: clamp(18px, 2.6vw, 28px);
  background: var(--ink-2);
}

.page-about .about-collab h3 {
  margin: 0 0 12px;
  font-size: 17px;
  font-weight: 800;
  color: var(--gold);
}

.page-about .about-collab p {
  margin: 0 0 12px;
  font-size: 14px;
  line-height: 1.65;
  color: var(--paper-2);
}

.page-about .about-collab .btn {
  display: inline-block;
  margin-top: 4px;
  padding: 10px 18px;
  border: 1px solid var(--steel);
  color: var(--paper);
  font-size: 13px;
  text-decoration: none;
  transition: border-color 160ms ease, color 160ms ease;
}

.page-about .about-collab .btn:hover,
.page-about .about-collab .btn:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
}

/* ---------- 06 今天 ---------- */
.page-about .about-now {
  display: grid;
  gap: clamp(20px, 3vw, 30px);
}

.page-about .about-now-main p {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.68;
  color: var(--paper-2);
}

.page-about .about-now-side {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
  align-self: start;
}

.page-about .now-figure {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px 12px;
  background: var(--ink-2);
}

.page-about .now-figure b {
  font-family: var(--font-mono);
  font-size: clamp(20px, 3vw, 28px);
  line-height: 1;
  color: var(--cyan);
}

.page-about .now-figure span {
  font-size: 11px;
  line-height: 1.4;
  color: var(--steel);
}

.page-about .about-cta {
  margin-top: clamp(26px, 4vw, 44px);
  padding-top: clamp(18px, 2.6vw, 28px);
  border-top: 1px solid var(--grid);
}

.page-about .about-cta h3 {
  margin: 0 0 14px;
  font-size: 16px;
  letter-spacing: 0.03em;
  color: var(--paper);
}

.page-about .about-cta-links {
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

.page-about .about-cta-links a {
  display: block;
  padding: 16px;
  background: var(--ink-2);
  text-decoration: none;
  transition: background 160ms ease, box-shadow 160ms ease;
}

.page-about .about-cta-links a:hover,
.page-about .about-cta-links a:focus-visible {
  background: var(--ink-3);
  box-shadow: inset 3px 0 0 var(--gold);
}

.page-about .about-cta-links b {
  display: block;
  margin-bottom: 4px;
  font-size: 15px;
  color: var(--gold);
}

.page-about .about-cta-links span {
  font-size: 13px;
  line-height: 1.55;
  color: var(--paper-2);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-board {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

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

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

  .page-about .flow-step {
    grid-template-columns: 64px 1fr;
    padding: 16px 18px;
  }
}

@media (min-width: 960px) {
  .page-about .about-hero {
    grid-template-columns: 7fr 5fr;
    align-items: end;
  }

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

  .page-about .about-origin-grid {
    grid-template-columns: 7fr 5fr;
    align-items: start;
  }

  .page-about .about-data-grid {
    grid-template-columns: 5fr 7fr;
    align-items: start;
  }

  .page-about .about-team-grid {
    grid-template-columns: 6fr 6fr;
    align-items: start;
  }

  .page-about .about-now {
    grid-template-columns: 7fr 5fr;
    align-items: start;
  }

  .page-about .about-now-side {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .metric b {
    animation: none;
  }

  .page-about .about-toc a,
  .page-about .about-board-item,
  .page-about .flow-step,
  .page-about .phase-card,
  .page-about .about-cta-links a,
  .page-about .about-collab .btn {
    transition: none;
  }
}