.page-about {
  background: var(--pitch);
  color: var(--white);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding-top: calc(var(--header-h) + 32px);
  padding-bottom: 56px;
  border-bottom: 3px solid var(--line-green);
  overflow: hidden;
}
.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(90deg, rgba(255, 255, 255, 0.045) 0 1px, transparent 1px 76px);
  pointer-events: none;
}
.page-about .about-hero-inner {
  position: relative;
  display: grid;
  gap: 36px;
  align-items: end;
}
.page-about .breadcrumb-link {
  color: var(--moss);
}
.page-about .breadcrumb-item[aria-current="page"] {
  color: var(--whistle);
}
.page-about .about-hero .page-title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(34px, 8.6vw, 84px);
  line-height: 1.02;
  letter-spacing: -0.02em;
  margin: 12px 0 0;
  max-width: 15em;
}
.page-about .about-hero .page-lead {
  color: var(--moss);
  font-size: 16px;
  line-height: 1.75;
  max-width: 36em;
  margin-top: 20px;
}
.page-about .hero-facts {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 32px;
  margin-top: 28px;
  padding-top: 22px;
  border-top: 1px solid var(--line-green);
}
.page-about .hero-fact {
  display: flex;
  align-items: baseline;
  gap: 10px;
}
.page-about .hero-fact-num {
  font-family: var(--font-mono);
  font-size: 30px;
  font-weight: 700;
  color: var(--whistle);
  line-height: 1;
}
.page-about .hero-fact-label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--moss);
}
.page-about .about-hero-media {
  margin: 0;
  border: 3px solid var(--line-green);
  box-shadow: var(--shadow-hard);
  background: var(--pitch-2);
  max-height: 460px;
  overflow: hidden;
}
.page-about .about-hero-media img {
  display: block;
  width: 100%;
  height: 100%;
  max-height: 460px;
  object-fit: cover;
}
.page-about .about-hero-media .media-frame-label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--pitch);
  background: var(--whistle);
  padding: 8px 12px;
}

/* ---------- 索引条 ---------- */
.page-about .index-bar {
  border-bottom: 3px solid var(--line-green);
  background: var(--pitch);
}
.page-about .index-bar-inner {
  gap: 8px;
}
.page-about .index-bar-link {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--moss);
  border: 1px solid var(--line-green);
  padding: 6px 10px;
  white-space: nowrap;
}
.page-about .index-bar-link:hover,
.page-about .index-bar-link[aria-current="true"] {
  color: var(--pitch);
  background: var(--whistle);
  border-color: var(--whistle);
}

/* ---------- 章节基座 ---------- */
.page-about .section {
  padding-block: 64px;
}
.page-about .section-head {
  max-width: 44em;
  margin-bottom: 40px;
}
.page-about .section-title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(28px, 5.4vw, 52px);
  line-height: 1.08;
  letter-spacing: -0.015em;
  margin: 10px 0 0;
}
.page-about .section-lead {
  color: var(--moss);
  font-size: 16px;
  line-height: 1.75;
  margin-top: 14px;
  max-width: 34em;
}
.page-about .section--paper .section-lead {
  color: var(--pitch-2);
}
.page-about .inline-link {
  color: var(--whistle);
  text-decoration: underline;
  text-underline-offset: 4px;
}
.page-about .section--paper .inline-link {
  color: var(--report-red);
}

/* ---------- 时间线 ---------- */
.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 30px;
  border-left: 3px solid var(--line-green);
}
.page-about .timeline-item {
  position: relative;
  padding-bottom: 40px;
}
.page-about .timeline-item:last-child {
  padding-bottom: 0;
}
.page-about .timeline-node {
  position: absolute;
  left: -41px;
  top: 6px;
  width: 16px;
  height: 16px;
  background: var(--pitch);
  border: 3px solid var(--line-green);
  transition: background 180ms var(--ease), border-color 180ms var(--ease);
}
.page-about .timeline-item.is-visible .timeline-node {
  background: var(--whistle);
  border-color: var(--whistle);
  box-shadow: 0 0 0 6px rgba(255, 198, 26, 0.14);
}
.page-about .timeline-stage {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--whistle);
  margin: 0 0 8px;
}
.page-about .timeline-title {
  font-size: 20px;
  font-weight: 700;
  line-height: 1.4;
  margin: 0 0 10px;
}
.page-about .timeline-text {
  color: var(--moss);
  font-size: 15px;
  line-height: 1.8;
  margin: 0;
  max-width: 40em;
}

/* ---------- 团队分工 ---------- */
.page-about .about-crew {
  border-top: 3px solid var(--line-green);
  border-bottom: 3px solid var(--line-green);
}
.page-about .crew-total {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 16px 24px;
  margin: 0 0 40px;
  padding-bottom: 24px;
  border-bottom: 1px dashed var(--line-green);
}
.page-about .crew-total-num {
  font-family: var(--font-mono);
  font-size: clamp(72px, 18vw, 148px);
  font-weight: 700;
  line-height: 0.82;
  color: var(--whistle);
  letter-spacing: -0.04em;
}
.page-about .crew-total-label {
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.9;
  letter-spacing: 0.06em;
  color: var(--moss);
  max-width: 30em;
}
.page-about .skilltree-svg {
  display: none;
  width: 100%;
  height: 64px;
}
.page-about .skilltree-nodes {
  display: grid;
  gap: 16px;
}
.page-about .skill-node {
  border: 3px solid var(--line-green);
  border-top-color: var(--whistle);
  background: var(--pitch);
  padding: 18px 16px;
  transition: border-color 160ms var(--ease), transform 160ms var(--ease), box-shadow 160ms var(--ease);
}
.page-about .skill-node:hover,
.page-about .skill-node:focus-within,
.page-about .skill-node:focus {
  border-color: var(--whistle);
  transform: translateY(-4px);
  box-shadow: var(--shadow-hard-sm);
  outline: none;
}
.page-about .skill-count {
  font-family: var(--font-mono);
  font-size: 40px;
  font-weight: 700;
  line-height: 1;
  color: var(--whistle);
  margin: 0 0 10px;
}
.page-about .skill-name {
  font-size: 18px;
  font-weight: 700;
  margin: 0 0 6px;
}
.page-about .skill-duty {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  color: var(--moss);
  margin: 0;
}
.page-about .skill-desc {
  font-size: 14px;
  line-height: 1.8;
  color: var(--moss);
  margin: 0;
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height 220ms var(--ease), opacity 180ms var(--ease), margin-top 180ms var(--ease);
}
.page-about .skill-node:hover .skill-desc,
.page-about .skill-node:focus .skill-desc,
.page-about .skill-node:focus-within .skill-desc {
  max-height: 240px;
  opacity: 1;
  margin-top: 12px;
}

/* ---------- 一轮时间表 ---------- */
.page-about .about-runbook {
  color: var(--pitch);
  border-bottom: 3px solid var(--pitch-2);
}
.page-about .runbook-grid {
  display: grid;
  gap: 32px;
  align-items: start;
}
.page-about .runbook-media {
  margin: 0;
  border: 3px solid var(--pitch);
  box-shadow: var(--shadow-hard);
  background: var(--paper-gray);
}
.page-about .runbook-media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}
.page-about .runbook-media .media-frame-label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  background: var(--pitch);
  color: var(--whistle);
  padding: 8px 12px;
}
.page-about .runbook {
  list-style: none;
  margin: 0;
  padding: 0;
}
.page-about .run-item {
  padding: 18px 0;
  border-bottom: 1px solid var(--paper-gray);
}
.page-about .run-item:first-child {
  padding-top: 0;
}
.page-about .run-time {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  background: var(--pitch);
  color: var(--whistle);
  padding: 5px 10px;
  margin: 0 0 10px;
}
.page-about .run-title {
  font-size: 18px;
  font-weight: 700;
  margin: 0 0 8px;
  color: var(--pitch);
}
.page-about .run-text {
  font-size: 15px;
  line-height: 1.8;
  margin: 0 0 8px;
  color: var(--pitch-2);
  max-width: 38em;
}
.page-about .run-owner {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  color: var(--pitch-2);
  margin: 0;
  padding-left: 10px;
  border-left: 3px solid var(--report-red);
}
.page-about .runbook-foot {
  margin: 32px 0 0;
  font-size: 15px;
  color: var(--pitch-2);
}

/* ---------- 更正 ---------- */
.page-about .correction-grid {
  display: grid;
  gap: 36px;
}
.page-about .correction-text {
  font-size: 15px;
  line-height: 1.85;
  color: var(--moss);
  margin: 18px 0 0;
  max-width: 36em;
}
.page-about .correction-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
}
.page-about .correction-step {
  border: 3px solid var(--line-green);
  padding: 18px 16px;
  background: var(--pitch-2);
}
.page-about .correction-no {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--report-red);
  margin-bottom: 8px;
}
.page-about .correction-title {
  font-size: 18px;
  font-weight: 700;
  margin: 0 0 8px;
}
.page-about .correction-desc {
  font-size: 14px;
  line-height: 1.8;
  color: var(--moss);
  margin: 0;
}

/* ---------- 合作生态 ---------- */
.page-about .about-partners {
  border-top: 3px solid var(--line-green);
}
.page-about .tabs-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 28px;
}
.page-about .tab {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--moss);
  background: transparent;
  border: 3px solid var(--line-green);
  padding: 10px 14px;
  cursor: pointer;
  transition: background 140ms var(--ease), color 140ms var(--ease), border-color 140ms var(--ease);
}
.page-about .tab:hover {
  border-color: var(--whistle);
  color: var(--whistle);
}
.page-about .tab[aria-selected="true"] {
  background: var(--whistle);
  border-color: var(--whistle);
  color: var(--pitch);
  font-weight: 700;
}
.page-about .tab:focus-visible {
  outline: 3px solid var(--whistle-soft);
  outline-offset: 2px;
}
.page-about .partner-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 3px solid var(--line-green);
}
.page-about .partner-item {
  display: grid;
  grid-template-columns: 40px 1fr;
  gap: 6px 14px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line-green);
  align-items: baseline;
}
.page-about .partner-no {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--whistle);
}
.page-about .partner-name {
  font-size: 16px;
  font-weight: 700;
  margin: 0;
  color: var(--white);
}
.page-about .partner-role {
  grid-column: 2;
  font-size: 14px;
  line-height: 1.75;
  color: var(--moss);
  margin: 0;
}
.page-about .partner-item .tag {
  grid-column: 2;
  justify-self: start;
  margin-top: 4px;
}
.page-about .partner-note {
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.9;
  letter-spacing: 0.03em;
  color: var(--moss);
  margin: 20px 0 0;
  max-width: 46em;
}
.page-about .partners-foot {
  margin: 32px 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--moss);
  max-width: 40em;
}

/* ---------- 西安 ---------- */
.page-about .xian-figure {
  position: relative;
  margin: 0;
  border-top: 3px solid var(--line-green);
  border-bottom: 3px solid var(--line-green);
}
.page-about .xian-figure img {
  display: block;
  width: 100%;
  height: clamp(180px, 42vw, 420px);
  object-fit: cover;
  filter: saturate(0.85);
}
.page-about .xian-caption {
  position: absolute;
  left: 16px;
  bottom: 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  background: var(--pitch);
  color: var(--whistle);
  border: 2px solid var(--whistle);
  padding: 6px 10px;
}
.page-about .xian-inner {
  padding-top: 48px;
  padding-bottom: 8px;
}
.page-about .xian-cols {
  display: grid;
  gap: 20px;
  margin-top: 20px;
}
.page-about .xian-text {
  font-size: 15px;
  line-height: 1.85;
  color: var(--moss);
  margin: 0;
  max-width: 36em;
}
.page-about .xian-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 32px;
}

/* ---------- 平板 ---------- */
@media (min-width: 720px) {
  .page-about .section {
    padding-block: 80px;
  }
  .page-about .about-hero {
    padding-top: calc(var(--header-h) + 48px);
    padding-bottom: 72px;
  }
  .page-about .about-hero-inner {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    gap: 48px;
  }
  .page-about .about-hero-media {
    max-height: 520px;
  }
  .page-about .about-hero-media img {
    max-height: 520px;
  }
  .page-about .skilltree-nodes {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
  }
  .page-about .correction-steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .correction-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
    gap: 48px;
    align-items: start;
  }
  .page-about .partner-item {
    grid-template-columns: 48px minmax(0, 1fr) auto;
    gap: 4px 16px;
  }
  .page-about .partner-role {
    grid-column: 2;
  }
  .page-about .partner-item .tag {
    grid-column: 3;
    grid-row: 1 / span 2;
    align-self: start;
    margin-top: 2px;
  }
  .page-about .xian-cols {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 32px;
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 1024px) {
  .page-about .section {
    padding-block: 96px;
  }
  .page-about .timeline {
    padding-left: 44px;
    margin-left: 8px;
  }
  .page-about .timeline-node {
    left: -55px;
    width: 20px;
    height: 20px;
  }
  .page-about .timeline-item {
    padding-bottom: 48px;
  }
  .page-about .timeline-title {
    font-size: 24px;
  }
  .page-about .skilltree-svg {
    display: block;
  }
  .page-about .skilltree-nodes {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .runbook-grid {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
    gap: 48px;
  }
  .page-about .crew-total {
    gap: 20px 36px;
  }
  .page-about .xian-figure img {
    height: 420px;
  }
}

/* ---------- 触屏设备：说明默认展开 ---------- */
@media (hover: none) {
  .page-about .skill-desc {
    max-height: none;
    opacity: 1;
    margin-top: 12px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .skill-node,
  .page-about .timeline-node,
  .page-about .skill-desc,
  .page-about .tab {
    transition: color 140ms linear, background 140ms linear, border-color 140ms linear;
    transform: none;
  }
  .page-about .skill-node:hover,
  .page-about .skill-node:focus,
  .page-about .skill-node:focus-within {
    transform: none;
  }
}