.page-about {
  --about-rail-w: 172px;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
}

/* 首屏 */
.page-about .about-mast {
  position: relative;
  overflow: hidden;
  padding: clamp(24px, 5vw, 44px) 0 clamp(28px, 5vw, 52px);
  border-bottom: 3px solid var(--ink);
  background: var(--paper);
}

.page-about .about-mast::after {
  content: "";
  position: absolute;
  right: -40px;
  bottom: -70px;
  width: 260px;
  height: 260px;
  background: repeating-linear-gradient(135deg, rgba(18, 58, 90, 0.14) 0 2px, transparent 2px 12px);
  clip-path: polygon(0 100%, 0 56%, 20% 56%, 20% 40%, 40% 40%, 40% 24%, 60% 24%, 60% 40%, 80% 40%, 80% 56%, 100% 56%, 100% 100%);
  pointer-events: none;
}

.page-about .about-mast .eyebrow {
  margin-top: 18px;
}

.page-about h1 {
  position: relative;
  z-index: 1;
  margin: 10px 0 0;
  max-width: 22ch;
  font-size: clamp(1.9rem, 7vw, 3.5rem);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: -0.02em;
}

.page-about .about-lead {
  position: relative;
  z-index: 1;
  margin: 18px 0 0;
  max-width: 38ch;
  font-size: clamp(0.98rem, 2.6vw, 1.1rem);
  line-height: 1.85;
  color: var(--deep);
}

.page-about .about-stats {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-stat {
  border: 2px solid var(--ink);
  background: var(--paper);
  box-shadow: var(--shadow-soft);
  padding: 12px 14px;
}

.page-about .about-stat:first-child {
  background: var(--orange-soft);
}

.page-about .about-stat-num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.4rem, 5vw, 1.9rem);
  font-weight: 700;
  line-height: 1.1;
  border-bottom: 2px solid var(--ink);
  padding-bottom: 4px;
  margin-bottom: 6px;
}

.page-about .about-stat-label {
  display: block;
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--deep);
}

/* 索引目录 */
.page-about .about-index {
  padding: clamp(26px, 5vw, 44px) 0;
  background: var(--paper);
  border-bottom: 2px solid var(--line);
}

.page-about .about-index-title {
  margin: 0;
  font-size: clamp(1.25rem, 4vw, 1.6rem);
  font-weight: 800;
  letter-spacing: -0.01em;
}

.page-about .about-index-hint {
  margin: 6px 0 16px;
  font-size: 0.9rem;
  color: var(--blue);
}

.page-about .about-index .index-list {
  columns: 1;
  margin: 0;
}

.page-about .about-index .index-link {
  display: block;
  padding: 8px 0 8px 14px;
  min-height: 44px;
  border-bottom: 2px solid var(--line);
  font-weight: 600;
}

/* 分节通用 */
.page-about .about-section {
  padding: clamp(34px, 6vw, 68px) 0;
  border-bottom: 2px solid var(--line);
}

.page-about .about-section--warm {
  background: var(--warm);
}

.page-about .about-split {
  display: grid;
  gap: 14px;
}

.page-about .about-rail {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  padding-bottom: 12px;
  border-bottom: 3px solid var(--ink);
}

.page-about .about-rail-num {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1;
  padding: 0 6px 2px;
  color: var(--ink);
  background: var(--orange-soft);
  border-bottom: 2px solid var(--ink);
}

.page-about .about-rail-label {
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--deep);
}

.page-about .about-body h2 {
  margin: 0 0 14px;
  font-size: clamp(1.45rem, 4.6vw, 2.15rem);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.page-about .about-body-lead,
.page-about .about-body-tail {
  margin: 0 0 20px;
  max-width: 38ch;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--deep);
}

.page-about .about-body-tail {
  margin: 20px 0 0;
}

.page-about .about-body .prose p {
  max-width: 38ch;
  line-height: 1.85;
  margin: 0 0 14px;
}

/* 旁注卡片 */
.page-about .about-note {
  margin-top: 22px;
  padding: 14px 16px;
  background: var(--paper);
  border: 2px solid var(--ink);
  border-left: 6px solid var(--orange);
  box-shadow: var(--shadow-soft);
}

.page-about .about-note-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  color: var(--ink);
  background: var(--orange-soft);
  padding: 2px 8px;
  margin-bottom: 8px;
}

.page-about .about-note p {
  margin: 0;
  font-size: 0.94rem;
  line-height: 1.8;
  color: var(--deep);
}

/* 图片容器 */
.page-about .about-media {
  margin: 0 0 24px;
  border: 3px solid var(--ink);
  background: var(--paper);
  box-shadow: var(--shadow-hard);
}

.page-about .about-media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .about-media--team {
  box-shadow: var(--shadow-soft);
}

/* 时间线 */
.page-about .about-track {
  list-style: none;
  margin: 0;
  padding: 0 0 0 20px;
  border-left: 3px solid var(--ink);
}

.page-about .about-node {
  position: relative;
  padding: 0 0 26px 6px;
}

.page-about .about-node::before {
  content: "";
  position: absolute;
  left: -31px;
  top: 4px;
  width: 14px;
  height: 14px;
  background: var(--paper);
  border: 3px solid var(--ink);
  box-sizing: content-box;
}

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

.page-about .about-node-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 6px;
}

.page-about .about-node-id {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  padding: 2px 8px;
  background: var(--orange-soft);
  border-bottom: 2px solid var(--ink);
}

.page-about .about-node h3 {
  margin: 0 0 6px;
  font-size: 1.08rem;
  font-weight: 800;
  line-height: 1.4;
}

.page-about .about-node p {
  margin: 0;
  max-width: 36ch;
  font-size: 0.94rem;
  line-height: 1.8;
  color: var(--deep);
}

/* 团队折叠组 */
.page-about .about-team-panels {
  display: grid;
  gap: 12px;
  margin-top: 22px;
}

.page-about .about-team-panels .panel-summary {
  min-height: 44px;
}

.page-about .about-team-panels .panel-body p {
  margin: 0;
  max-width: 38ch;
  line-height: 1.8;
}

/* 更新节奏 */
.page-about .about-cadence {
  display: grid;
  gap: 16px;
  margin-top: 4px;
}

.page-about .about-cad-card .card-head {
  border-bottom: 2px solid var(--line);
  padding-bottom: 8px;
}

.page-about .about-cad-step {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  padding: 3px 8px;
  color: var(--ink);
  background: var(--jade-soft);
  border-bottom: 2px solid var(--jade);
  margin-bottom: 6px;
}

.page-about .about-cad-card .card-title {
  margin: 0;
  font-size: 1.1rem;
  font-weight: 800;
}

.page-about .about-cad-card .card-body p {
  margin: 8px 0 0;
  font-size: 0.94rem;
  line-height: 1.8;
  color: var(--deep);
}

/* 覆盖与使用场景 */
.page-about .about-coverage-notes {
  display: grid;
  gap: 10px;
}

.page-about .about-note-item {
  display: grid;
  grid-template-columns: 68px minmax(0, 1fr);
  align-items: start;
  gap: 12px;
  padding: 12px 14px;
  background: var(--paper);
  border: 2px solid var(--ink);
  box-shadow: var(--shadow-soft);
}

.page-about .about-note-num {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  padding: 2px 6px;
  background: var(--orange-soft);
  border-bottom: 2px solid var(--ink);
  text-align: center;
}

.page-about .about-note-item p {
  margin: 0;
  font-size: 0.93rem;
  line-height: 1.75;
  color: var(--deep);
}

/* 生态成果 */
.page-about .about-eco {
  list-style: none;
  margin: 4px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-eco-item {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr);
  align-items: center;
  gap: 14px;
  padding: 14px 16px;
  background: var(--paper);
  border: 2px solid var(--ink);
  box-shadow: var(--shadow-soft);
}

.page-about .about-eco-num {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1;
  color: var(--ink);
  background: var(--jade-soft);
  border-bottom: 2px solid var(--jade);
  padding: 4px 0 6px;
  text-align: center;
}

.page-about .about-eco-text {
  font-size: 0.93rem;
  line-height: 1.7;
  color: var(--deep);
}

/* 收束区 */
.page-about .about-cta {
  padding: clamp(34px, 6vw, 64px) 0 clamp(40px, 7vw, 72px);
  background: var(--deep);
  color: var(--paper);
  border-top: 4px solid var(--orange);
}

.page-about .about-cta h2 {
  margin: 0 0 10px;
  font-size: clamp(1.4rem, 4.6vw, 2rem);
  font-weight: 800;
  line-height: 1.3;
  color: var(--paper);
}

.page-about .about-cta p {
  margin: 0 0 22px;
  max-width: 38ch;
  font-size: 0.96rem;
  line-height: 1.85;
  color: rgba(255, 253, 248, 0.86);
}

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

.page-about .about-cta-links .btn {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

/* 平板与桌面 */
@media (min-width: 640px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 14px;
  }

  .page-about .about-index .index-list {
    columns: 2;
    column-gap: 32px;
  }

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

  .page-about .about-cadence .about-cad-card:nth-child(2) {
    margin-top: 18px;
  }

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

  .page-about .about-note-item {
    grid-template-columns: minmax(0, 1fr);
    gap: 8px;
  }

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

@media (min-width: 900px) {
  .page-about .about-split {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(28px, 4vw, 56px);
    align-items: start;
  }

  .page-about .about-rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
    padding-bottom: 0;
    border-bottom: 0;
    border-right: 3px solid var(--ink);
    padding-right: 18px;
    position: sticky;
    top: 24px;
  }

  .page-about .about-rail-num {
    font-size: 2rem;
  }

  .page-about .about-index .index-list {
    columns: 3;
  }

  .page-about .about-cadence {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    align-items: start;
  }

  .page-about .about-cadence .about-cad-card:nth-child(2) {
    margin-top: 26px;
  }

  .page-about .about-cadence .about-cad-card:nth-child(3) {
    margin-top: 10px;
  }

  .page-about .about-media--team {
    max-width: 620px;
  }

  .page-about .about-eco {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }
}