.page-about {
  --about-w: 46ch;
  --about-gap: clamp(44px, 7vw, 88px);
  position: relative;
  background: var(--void);
  color: var(--text);
  padding-bottom: clamp(64px, 9vw, 120px);
  overflow-x: hidden;
}

.page-about::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 620px;
  background:
    radial-gradient(ellipse at 14% -12%, var(--cyan-veil), transparent 60%),
    radial-gradient(ellipse at 88% 8%, var(--violet-veil), transparent 58%);
  pointer-events: none;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding-top: calc(var(--header-h) + 44px);
  padding-bottom: clamp(28px, 4vw, 44px);
  max-width: 900px;
}

.page-about .about-kicker {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--cyan);
  margin: 0 0 18px;
}

.page-about h1 {
  font-family: var(--font-display);
  font-size: clamp(30px, 5.6vw, 64px);
  line-height: 1.12;
  font-weight: 800;
  letter-spacing: -0.012em;
  margin: 0;
  max-width: 20ch;
}

.page-about .about-lead {
  margin: 24px 0 0;
  max-width: 46ch;
  font-size: clamp(15px, 1.9vw, 18px);
  line-height: 1.9;
  color: var(--muted);
}

.page-about .about-facts {
  list-style: none;
  margin: 38px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--edge-soft);
  border: 1px solid var(--edge-soft);
}

.page-about .about-facts li {
  background: var(--panel);
  padding: 16px 18px 18px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .about-facts .mono {
  font-size: clamp(24px, 3.4vw, 34px);
  line-height: 1;
  font-weight: 700;
}

.page-about .fact-a { color: var(--cyan); }
.page-about .fact-b { color: var(--amber); }
.page-about .fact-c { color: var(--violet); }
.page-about .fact-d { color: var(--text); }

.page-about .fact-label {
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--muted);
}

/* ---------- 双栏布局 ---------- */
.page-about .about-layout {
  position: relative;
  display: grid;
  gap: 36px;
}

.page-about .about-toc {
  border-top: 1px solid var(--edge);
  padding-top: 14px;
}

.page-about .toc-title {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 10px;
}

.page-about .about-toc ol {
  list-style: none;
  margin: 0;
  padding: 0 0 6px;
  display: flex;
  gap: 6px;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .about-toc ol::-webkit-scrollbar {
  display: none;
}

.page-about .about-toc a {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 8px 12px;
  font-size: 13px;
  line-height: 1.4;
  color: var(--muted);
  text-decoration: none;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .about-toc a .mono {
  font-size: 11px;
  color: var(--edge);
  transition: color 0.2s var(--ease);
}

.page-about .about-toc a:hover,
.page-about .about-toc a:focus-visible {
  color: var(--text);
}

.page-about .about-toc a.is-current {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .about-toc a.is-current .mono {
  color: var(--cyan);
}

/* ---------- 章节 ---------- */
.page-about .about-section {
  padding-top: clamp(52px, 6.5vw, 84px);
  scroll-margin-top: calc(var(--header-h-stuck) + 24px);
}

.page-about .about-section:first-child {
  padding-top: 8px;
}

.page-about .section-head {
  display: flex;
  align-items: flex-start;
  gap: clamp(14px, 2vw, 24px);
  margin-bottom: 24px;
}

.page-about .section-no {
  flex: none;
  font-family: var(--font-mono);
  font-size: clamp(42px, 7.4vw, 92px);
  line-height: 0.82;
  font-weight: 700;
  color: var(--edge);
  letter-spacing: -0.03em;
}

@supports (-webkit-text-stroke: 1px currentColor) {
  .page-about .section-no {
    color: transparent;
    -webkit-text-stroke: 1px var(--edge);
  }
}

.page-about .section-title {
  padding-top: 8px;
  font-family: var(--font-display);
  font-size: clamp(20px, 2.8vw, 32px);
  line-height: 1.28;
  font-weight: 700;
  margin: 0;
}

.page-about .about-prose p {
  max-width: var(--about-w);
  margin: 0 0 18px;
  font-size: clamp(14.5px, 1.6vw, 16px);
  line-height: 1.95;
  color: var(--text);
}

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

/* ---------- 年份刻度带 ---------- */
.page-about .year-ruler {
  margin: clamp(34px, 4.5vw, 52px) 0 0;
  padding: 20px 0 14px;
  border-top: 1px solid var(--edge-soft);
  border-bottom: 1px solid var(--edge-soft);
  max-width: 860px;
}

.page-about .year-ruler svg {
  display: block;
  width: 100%;
  height: 76px;
}

.page-about .year-ruler .tick {
  stroke: var(--cyan);
  stroke-width: 2;
  opacity: 0.32;
}

.page-about .year-ruler .base {
  opacity: 0.55;
}

.page-about .year-ruler-legend {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  margin-top: 6px;
  font-size: 11px;
  color: var(--muted);
}

.page-about .year-ruler-legend span:last-child {
  text-align: right;
}

/* ---------- 三条线 ---------- */
.page-about .tracks {
  display: grid;
  gap: 14px;
  margin: 30px 0 28px;
}

.page-about .track {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--edge-soft);
  border-left: 3px solid var(--track-color, var(--edge));
  padding: 22px 20px 20px;
  clip-path: polygon(0 0, calc(100% - 20px) 0, 100% 20px, 100% 100%, 0 100%);
}

.page-about .track--review { --track-color: var(--amber); }
.page-about .track--config { --track-color: var(--cyan); }
.page-about .track--schedule { --track-color: var(--violet); }

.page-about .track-no {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--track-color);
  margin: 0 0 12px;
}

.page-about .track h3 {
  font-size: 17px;
  line-height: 1.45;
  font-weight: 700;
  margin: 0 0 10px;
}

.page-about .track p:last-child {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.85;
  color: var(--muted);
}

/* ---------- 团队图 ---------- */
.page-about .team-map {
  position: relative;
  display: grid;
  gap: 12px;
  margin: 28px 0 6px;
}

.page-about .team-map::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: min(420px, 78%);
  aspect-ratio: 1 / 1;
  transform: translate(-50%, -50%);
  background: radial-gradient(circle, var(--cyan-veil), transparent 68%);
  pointer-events: none;
}

.page-about .team-nodes {
  display: contents;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .team-core {
  text-align: center;
  padding: 22px 16px;
  background: var(--panel);
  border: 1px solid var(--edge);
  clip-path: polygon(18px 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%, 0 18px);
}

.page-about .team-core .mono {
  display: block;
  font-size: clamp(36px, 5vw, 52px);
  line-height: 1;
  font-weight: 700;
  color: var(--cyan);
}

.page-about .team-core span:last-child {
  display: block;
  margin-top: 8px;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--muted);
}

.page-about .team-node {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--edge-soft);
  border-left: 3px solid var(--node-color, var(--edge));
  padding: 16px 18px;
}

.page-about .team-node--editor { --node-color: var(--amber); }
.page-about .team-node--data { --node-color: var(--cyan); }
.page-about .team-node--tech { --node-color: var(--violet); }
.page-about .team-node--ops { --node-color: var(--cyan-dim); }

.page-about .team-num {
  display: block;
  font-size: 30px;
  line-height: 1;
  font-weight: 700;
  color: var(--node-color);
}

.page-about .team-role {
  display: block;
  margin-top: 10px;
  font-size: 15px;
  font-weight: 600;
}

.page-about .team-desc {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  margin: 0;
  font-size: 13px;
  line-height: 1.8;
  color: var(--muted);
  transition: max-height 0.35s var(--ease), opacity 0.3s var(--ease), margin-top 0.35s var(--ease);
}

/* ---------- 厂商协作流程 ---------- */
.page-about .partner-flow {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .flow-step {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--edge-soft);
  padding: 18px 16px 16px;
}

.page-about .flow-no {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .flow-step h3 {
  font-size: 16px;
  margin: 10px 0 8px;
  font-weight: 700;
}

.page-about .flow-step p {
  margin: 0;
  font-size: 13px;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 复核节奏 ---------- */
.page-about .cadence-grid {
  display: grid;
  gap: 18px;
  margin: 28px 0;
}

.page-about .cadence-item {
  border-top: 2px solid var(--c, var(--cyan));
  padding-top: 14px;
}

.page-about .cadence-item--config { --c: var(--cyan); }
.page-about .cadence-item--schedule { --c: var(--violet); }

.page-about .cadence-item .mono {
  display: block;
  font-size: clamp(34px, 5vw, 46px);
  line-height: 1;
  font-weight: 700;
  color: var(--c);
}

.page-about .cadence-cap {
  margin: 8px 0 10px;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--muted);
}

.page-about .cadence-item p:last-child {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--text);
  max-width: 34ch;
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: clamp(26px, 3.5vw, 40px) 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  background: var(--panel);
  border: 1px solid var(--edge-soft);
}

.page-about .about-figure figcaption {
  margin-top: 12px;
  max-width: 52ch;
  font-size: 12.5px;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 结尾 ---------- */
.page-about .about-cta {
  margin-top: clamp(36px, 5vw, 60px);
  padding: 26px 24px 28px;
  background: var(--panel);
  border: 1px solid var(--edge-soft);
  border-top: 2px solid var(--amber);
  clip-path: polygon(0 0, calc(100% - 22px) 0, 100% 22px, 100% 100%, 0 100%);
}

.page-about .about-cta p {
  margin: 0 0 20px;
  max-width: 52ch;
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--text);
}

.page-about .cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .tracks {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }
}

@media (max-width: 819px) {
  .page-about .team-desc {
    max-height: none;
    opacity: 1;
    margin-top: 10px;
  }
}

@media (min-width: 820px) {
  .page-about .team-map {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.9fr) minmax(0, 1fr);
    grid-template-rows: auto auto auto;
    align-items: center;
    gap: 22px 20px;
  }

  .page-about .team-core {
    grid-column: 2;
    grid-row: 2;
  }

  .page-about .team-node:nth-child(1) { grid-column: 1; grid-row: 1; }
  .page-about .team-node:nth-child(2) { grid-column: 3; grid-row: 1; }
  .page-about .team-node:nth-child(3) { grid-column: 1; grid-row: 3; }
  .page-about .team-node:nth-child(4) { grid-column: 3; grid-row: 3; }

  .page-about .team-node:hover .team-desc,
  .page-about .team-node:focus-within .team-desc {
    max-height: 180px;
    opacity: 1;
    margin-top: 10px;
  }

  .page-about .cadence-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 32px;
  }
}

@media (min-width: 900px) {
  .page-about .partner-flow {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 10px;
  }

  .page-about .flow-step:not(:last-child)::after {
    content: "";
    position: absolute;
    right: -10px;
    top: 32px;
    width: 10px;
    height: 2px;
    background: var(--cyan);
    opacity: 0.6;
    transform: rotate(-22deg);
    transform-origin: right center;
  }
}

@media (min-width: 1024px) {
  .page-about .about-layout {
    grid-template-columns: minmax(0, 1fr) 214px;
    gap: clamp(48px, 5vw, 76px);
    align-items: start;
  }

  .page-about .about-toc {
    grid-column: 2;
    grid-row: 1;
    position: sticky;
    top: calc(var(--header-h-stuck) + 28px);
    border-top: 1px solid var(--edge);
    padding-top: 16px;
  }

  .page-about .about-body {
    grid-column: 1;
    grid-row: 1;
    min-width: 0;
  }

  .page-about .about-toc ol {
    display: block;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-toc a {
    white-space: normal;
    align-items: flex-start;
    border-bottom: 0;
    border-left: 2px solid transparent;
    padding: 8px 10px;
    line-height: 1.5;
  }

  .page-about .about-toc a.is-current {
    border-bottom-color: transparent;
    border-left-color: var(--cyan);
    background: var(--cyan-veil);
  }
}

@media (min-width: 1200px) {
  .page-about .about-body {
    max-width: 880px;
  }
}