.page-about {
  --about-rail: 34px;
  --about-cut: 14px;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 20px var(--gutter) 72px;
  color: var(--ink-800);
  font-family: var(--font-sans);
}

.page-about .breadcrumb {
  margin-bottom: 18px;
  font-size: 13px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  display: grid;
  gap: 28px;
  padding-bottom: 8px;
}

.page-about .about-hero-copy h1 {
  margin: 10px 0 16px;
  font-size: clamp(28px, 6.4vw, 52px);
  line-height: 1.2;
  font-weight: 800;
  color: var(--ink-900);
  letter-spacing: -0.01em;
}

.page-about .about-hero-lead {
  max-width: 34em;
  margin: 0 0 22px;
  font-size: 16px;
  line-height: 1.75;
  color: var(--slate);
}

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

.page-about .about-hero-mark {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 26px 24px 30px;
  background: var(--ink-900);
  color: var(--white);
  clip-path: polygon(0 22px, 100% 0, 100% 100%, 0 calc(100% - 18px));
}

.page-about .about-hero-mark::before {
  content: "";
  position: absolute;
  top: -12px;
  right: -12px;
  width: 72%;
  height: 58px;
  background: var(--green-500);
  z-index: -1;
  clip-path: polygon(0 0, 100% 0, 100% 100%, 26px 100%);
}

.page-about .about-hero-mark-label {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--green-500);
}

.page-about .about-hero-mark-v {
  font-family: var(--font-mono);
  font-size: clamp(76px, 20vw, 132px);
  line-height: 0.92;
  font-weight: 700;
  color: var(--green-500);
  letter-spacing: -0.03em;
}

.page-about .about-hero-mark-note {
  font-size: 13px;
  line-height: 1.6;
  color: rgba(247, 249, 248, 0.72);
}

/* ---------- 关键数字条 ---------- */
.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 32px 0 8px;
  padding: 1px;
  background: var(--line);
  list-style: none;
}

.page-about .about-fact {
  background: var(--white);
  padding: 16px 16px 18px;
}

.page-about .about-fact-key {
  margin: 0 0 6px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--slate);
  font-family: var(--font-mono);
}

.page-about .about-fact-val {
  margin: 0;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink-900);
}

.page-about .about-fact-val .mono {
  font-size: 26px;
  line-height: 1;
  color: var(--orange-700);
  margin-right: 4px;
}

/* ---------- 章节骨架与时间轴 ---------- */
.page-about .about-chapter {
  display: grid;
  grid-template-columns: var(--about-rail) minmax(0, 1fr);
  gap: 12px;
  padding: 44px 0;
}

.page-about .chapter-rail {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  padding-top: 6px;
}

.page-about .chapter-rail::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 0;
  bottom: -88px;
  width: 2px;
  margin-left: -1px;
  background: var(--line);
  z-index: 0;
}

.page-about .about-chapter--end .chapter-rail::before {
  bottom: 0;
}

.page-about .chapter-dot {
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--orange-500);
  box-shadow: 0 0 0 4px var(--paper);
  z-index: 1;
}

.page-about .chapter-idx {
  z-index: 1;
  padding: 2px 0;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--slate);
  background: var(--paper);
}

.page-about .chapter-body h2 {
  margin: 0 0 16px;
  font-size: clamp(24px, 4.6vw, 38px);
  line-height: 1.28;
  font-weight: 800;
  color: var(--ink-900);
}

.page-about .chapter-body h3 {
  margin: 22px 0 8px;
  font-size: 17px;
  font-weight: 700;
  color: var(--ink-800);
}

.page-about .chapter-body p {
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.78;
  color: var(--slate);
}

.page-about .chapter-sub {
  position: relative;
  padding-left: 14px;
}

.page-about .chapter-sub::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  bottom: 6px;
  width: 3px;
  background: var(--green-500);
}

.page-about .chapter-tail {
  margin-top: 20px;
  font-size: 15px;
}

.page-about .chapter-tail a {
  color: var(--green-700);
  font-weight: 700;
  text-decoration: none;
  border-bottom: 2px solid var(--green-500);
  padding-bottom: 1px;
}

/* ---------- 横向色带 ---------- */
.page-about .about-band {
  display: grid;
  gap: 6px;
  margin: 8px 0;
  padding: 22px 22px 34px;
  background: var(--green-500);
  color: var(--ink-900);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 20px), 0 100%);
}

.page-about .about-band--ink {
  background: var(--ink-900);
  color: var(--white);
  padding: 34px 22px 22px;
  clip-path: polygon(0 20px, 100% 0, 100% 100%, 0 100%);
}

.page-about .band-index {
  font-size: 12px;
  letter-spacing: 0.14em;
  opacity: 0.72;
}

.page-about .band-text {
  margin: 0;
  font-size: 16px;
  line-height: 1.7;
  font-weight: 600;
}

.page-about .about-band--ink .band-text {
  color: var(--green-050);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 6px 0 24px;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  background: var(--green-050);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
}

.page-about .about-figure--wide img {
  aspect-ratio: 2 / 1;
}

.page-about .about-figure--side {
  margin: 0;
}

.page-about .about-figure--side img {
  aspect-ratio: 10 / 7;
}

.page-about .figure-cap {
  margin-top: 8px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--slate);
  letter-spacing: 0.04em;
}

/* ---------- 四道工序 ---------- */
.page-about .about-flow {
  list-style: none;
  margin: 8px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .flow-step {
  display: grid;
  gap: 10px;
  padding: 20px 18px;
  background: var(--white);
  border-left: 3px solid var(--green-500);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 14px), calc(100% - 14px) 100%, 0 100%);
}

.page-about .flow-idx {
  font-size: 13px;
  font-weight: 700;
  color: var(--orange-700);
  letter-spacing: 0.1em;
}

.page-about .flow-title {
  margin: 0 0 6px;
  font-size: 18px;
  font-weight: 700;
  color: var(--ink-900);
}

.page-about .flow-main p {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
}

.page-about .flow-output {
  padding: 12px 14px;
  background: var(--green-050);
}

.page-about .flow-out-key {
  display: block;
  margin-bottom: 4px;
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--green-700);
}

.page-about .flow-output p {
  margin: 0;
  font-size: 14px;
  line-height: 1.66;
  color: var(--ink-800);
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 20px 0 18px;
}

.page-about .team-card {
  padding: 18px 16px 20px;
  background: var(--green-050);
  clip-path: polygon(0 12px, 100% 0, 100% 100%, 0 100%);
  transition: background var(--dur) ease, color var(--dur) ease;
}

.page-about .team-num {
  display: block;
  font-size: 32px;
  line-height: 1;
  font-weight: 700;
  color: var(--ink-900);
}

.page-about .team-name {
  margin: 8px 0 6px;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink-800);
}

.page-about .team-note {
  margin: 0;
  font-size: 13px;
  line-height: 1.65;
  color: var(--slate);
}

.page-about .team-shift {
  margin-top: 4px;
  padding-left: 14px;
  border-left: 2px solid var(--line);
  font-size: 15px;
}

/* ---------- 版本时间轴 ---------- */
.page-about .version-track {
  position: relative;
  list-style: none;
  margin: 24px 0 0;
  padding: 0 0 0 26px;
}

.page-about .version-track::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 16px;
  bottom: 16px;
  width: 2px;
  background: var(--line);
}

.page-about .version-node {
  position: relative;
  padding-bottom: 10px;
}

.page-about .version-node::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 18px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--paper);
  border: 3px solid var(--green-500);
  box-sizing: content-box;
}

.page-about .version-item {
  background: var(--white);
  border: 1px solid var(--line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 12px), calc(100% - 12px) 100%, 0 100%);
}

.page-about .version-head {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
}

.page-about .version-head::-webkit-details-marker {
  display: none;
}

.page-about .version-head::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 20px;
  line-height: 1;
  color: var(--green-700);
}

.page-about .version-item[open] .version-head::after {
  content: "−";
  color: var(--orange-700);
}

.page-about .version-badge {
  flex: none;
  padding: 3px 8px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--orange-700);
  background: var(--paper);
  border: 1px solid var(--orange-500);
}

.page-about .version-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--ink-900);
  line-height: 1.5;
}

.page-about .version-detail {
  padding: 0 16px 16px;
}

.page-about .version-detail p {
  margin: 0;
  font-size: 15px;
  line-height: 1.74;
  color: var(--slate);
}

/* ---------- 覆盖范围 ---------- */
.page-about .coverage-grid {
  display: grid;
  gap: 22px;
  margin-top: 8px;
}

.page-about .fact-list {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
}

.page-about .fact-item {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  padding: 12px 14px;
  background: var(--white);
}

.page-about .fact-key {
  font-size: 14px;
  color: var(--slate);
}

.page-about .fact-val {
  font-size: 16px;
  font-weight: 700;
  color: var(--ink-900);
  white-space: nowrap;
}

/* ---------- 三张入口卡 ---------- */
.page-about .cta-grid {
  display: grid;
  gap: 12px;
  margin-top: 20px;
}

.page-about .cta-card {
  display: block;
  padding: 20px 18px 22px;
  background: var(--ink-900);
  color: var(--white);
  text-decoration: none;
  clip-path: polygon(0 14px, 100% 0, 100% 100%, 0 100%);
  transition: transform var(--dur) ease, background var(--dur) ease;
}

.page-about .cta-idx {
  display: block;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--green-500);
}

.page-about .cta-title {
  margin: 8px 0 8px;
  font-size: 18px;
  font-weight: 700;
  color: var(--white);
}

.page-about .cta-desc {
  margin: 0 0 14px;
  font-size: 14px;
  line-height: 1.7;
  color: rgba(247, 249, 248, 0.76);
}

.page-about .cta-go {
  font-size: 14px;
  font-weight: 700;
  color: var(--green-500);
  border-bottom: 2px solid var(--green-500);
  padding-bottom: 2px;
}

/* ---------- 悬停与焦点 ---------- */
.page-about .cta-card:hover,
.page-about .cta-card:focus-visible {
  background: var(--ink-800);
  transform: translate(-3px, -3px);
}

.page-about .team-card:hover,
.page-about .team-card:focus-within {
  background: var(--ink-800);
}

.page-about .team-card:hover .team-num,
.page-about .team-card:focus-within .team-num {
  color: var(--green-500);
}

.page-about .team-card:hover .team-name,
.page-about .team-card:focus-within .team-name {
  color: var(--white);
}

.page-about .team-card:hover .team-note,
.page-about .team-card:focus-within .team-note {
  color: rgba(247, 249, 248, 0.8);
}

.page-about .version-head:hover .version-title {
  color: var(--green-700);
}

/* ---------- 中等屏 ---------- */
@media (min-width: 700px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

  .page-about .about-flow .flow-step {
    grid-template-columns: 48px minmax(0, 1fr) minmax(0, 0.82fr);
    align-items: start;
    gap: 16px;
  }

  .page-about .flow-output {
    align-self: stretch;
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 960px) {
  .page-about {
    --about-rail: 62px;
    padding-bottom: 96px;
  }

  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 0.78fr);
    align-items: start;
    gap: 48px;
    padding: 24px 0 16px;
  }

  .page-about .about-hero-mark {
    margin-top: 26px;
    padding: 30px 28px 34px;
  }

  .page-about .about-chapter {
    gap: 32px;
    padding: 64px 0;
  }

  .page-about .chapter-rail {
    align-items: flex-start;
    padding-left: 4px;
    padding-top: 10px;
  }

  .page-about .chapter-rail::before {
    left: 9px;
    margin-left: 0;
    bottom: -128px;
  }

  .page-about .about-chapter--end .chapter-rail::before {
    bottom: 0;
  }

  .page-about .chapter-dot {
    margin-left: 0;
  }

  .page-about .chapter-idx {
    padding-left: 2px;
  }

  .page-about .about-band {
    padding: 26px 40px 40px;
  }

  .page-about .about-band--ink {
    padding: 40px 40px 26px;
  }

  .page-about .band-text {
    font-size: 18px;
    max-width: 46em;
  }

  .page-about .coverage-grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: start;
    gap: 36px;
  }

  .page-about .about-figure--side {
    margin-top: 8px;
  }

  .page-about .fact-list {
    margin-top: 22px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .cta-card,
  .page-about .team-card,
  .page-about .team-num,
  .page-about .team-name,
  .page-about .team-note,
  .page-about .version-head::after {
    transition: none;
  }

  .page-about .cta-card:hover,
  .page-about .cta-card:focus-visible {
    transform: none;
  }
}