.page-about {
  --about-gap: clamp(20px, 3vw, 32px);
  --about-lead: clamp(16px, 1.7vw, 17px);
  color: var(--text);
}

.page-about .breadcrumb {
  margin: 20px 0 6px;
}

/* ---------- 开场 ---------- */
.page-about .about-open {
  padding-top: clamp(10px, 2vw, 24px);
}

.page-about .open-grid {
  display: grid;
  gap: clamp(24px, 4vw, 44px);
  align-items: start;
}

.page-about .open-kicker {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--amber);
}

.page-about .open-lead h1 {
  margin: 0 0 18px;
  font-size: clamp(28px, 5.2vw, 44px);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: -0.02em;
  font-stretch: 95%;
}

.page-about .open-text {
  max-width: 34em;
  margin: 0 0 14px;
  font-size: var(--about-lead);
  line-height: 1.85;
  color: var(--text-2);
}

.page-about .open-facts {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 32px;
  margin-top: 26px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.page-about .fact {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .fact-num {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  color: var(--text);
}

.page-about .fact-label {
  font-size: 13px;
  color: var(--text-3);
}

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

.page-about .figure-frame {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--r);
  background: var(--ink-800);
  box-shadow: var(--shadow);
}

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

.page-about .figure-cap {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--text-3);
}

@media (min-width: 900px) {
  .page-about .open-grid {
    grid-template-columns: 4fr 8fr;
  }

  .page-about .open-lead {
    padding-top: 46px;
  }
}

/* ---------- 章节公共头 ---------- */
.page-about .methods,
.page-about .timeline {
  padding-top: clamp(44px, 6vw, 76px);
}

.page-about .section-head {
  margin-bottom: 22px;
}

.page-about .section-kicker {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--text-3);
}

.page-about .section-title {
  margin: 0;
  font-size: clamp(22px, 3.4vw, 32px);
  font-weight: 900;
  line-height: 1.2;
  letter-spacing: -0.01em;
  font-stretch: 95%;
}

.page-about .section-desc {
  max-width: 46em;
  margin: 10px 0 0;
  font-size: 16px;
  line-height: 1.85;
  color: var(--text-2);
}

/* ---------- 方法三原则 ---------- */
.page-about .method-grid {
  display: grid;
  gap: 14px;
}

.page-about .method-panel {
  padding: 18px 18px 16px;
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-top: 2px solid var(--indigo);
  border-radius: var(--r);
}

.page-about .method-panel:nth-child(2) {
  border-top-color: var(--violet);
}

.page-about .method-panel:nth-child(3) {
  border-top-color: var(--jade);
}

.page-about .method-sum {
  display: flex;
  align-items: baseline;
  gap: 10px;
  cursor: pointer;
  list-style: none;
}

.page-about .method-sum::-webkit-details-marker {
  display: none;
}

.page-about .method-sum::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--cyan);
}

.page-about .method-panel[open] .method-sum::after {
  content: "–";
}

.page-about .method-sum:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

.page-about .method-num {
  font-family: var(--font-mono);
  font-size: 13px;
  font-variant-numeric: tabular-nums;
  color: var(--text-3);
}

.page-about .method-name {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page-about .method-body {
  margin: 14px 0 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text-2);
}

.page-about .method-example {
  margin: 12px 0 0;
  padding: 10px 12px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-2);
  background: var(--ink-700);
  border-left: 2px solid var(--line);
  border-radius: 0 var(--r) var(--r) 0;
}

.page-about .method-figure {
  margin-top: clamp(20px, 3vw, 30px);
}

@media (min-width: 820px) {
  .page-about .method-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* ---------- 团队分工 ---------- */
.page-about .team {
  margin-top: clamp(34px, 5vw, 58px);
  padding: clamp(18px, 3vw, 30px);
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-radius: var(--r);
}

.page-about .panel-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 12px;
}

.page-about .panel-num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--text-3);
}

.page-about .panel-title {
  margin: 0;
  font-size: clamp(20px, 3vw, 26px);
  font-weight: 900;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.page-about .team-desc {
  max-width: 46em;
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text-2);
}

.page-about .team-bars {
  display: grid;
  gap: 16px;
  margin: 22px 0 0;
}

.page-about .team-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 8px 12px;
  align-items: center;
}

.page-about .team-name {
  font-size: 15px;
  font-weight: 500;
}

.page-about .team-count {
  font-family: var(--font-mono);
  font-size: 14px;
  font-variant-numeric: tabular-nums;
  color: var(--text-2);
}

.page-about .team-track {
  grid-column: 1 / -1;
  display: block;
  height: 10px;
  background: var(--ink-700);
  border-radius: 2px;
  overflow: hidden;
}

.page-about .team-fill {
  display: block;
  height: 100%;
  border-radius: 2px;
}

.page-about .team-fill--edit {
  width: 47.4%;
  background: var(--indigo);
}

.page-about .team-fill--check {
  width: 21.1%;
  background: var(--violet);
}

.page-about .team-fill--tech {
  width: 31.6%;
  background: var(--jade);
}

.page-about .team-steps {
  display: grid;
  gap: 12px;
  margin: 26px 0 0;
  padding: 18px 0 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.page-about .team-steps li {
  display: flex;
  gap: 10px;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--text-2);
}

.page-about .step-num {
  flex: none;
  font-family: var(--font-mono);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
  color: var(--text-3);
  padding-top: 2px;
}

@media (min-width: 820px) {
  .page-about .team-steps {
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
  }
}

/* ---------- 版本时间线 ---------- */
.page-about .timeline {
  display: grid;
  gap: clamp(22px, 3vw, 34px);
  align-items: start;
}

.page-about .axis-title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--text-3);
}

.page-about .axis-list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-left: 1px solid var(--line);
}

.page-about .axis-node {
  position: relative;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 12px 10px 20px;
  border: 1px solid transparent;
  border-radius: var(--r);
  text-decoration: none;
  color: var(--text-2);
  transition: background 160ms ease, color 160ms ease;
}

.page-about .axis-node:hover {
  background: var(--ink-800);
  color: var(--text);
}

.page-about .axis-node:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.page-about .axis-dot {
  position: absolute;
  left: -5px;
  top: 50%;
  width: 9px;
  height: 9px;
  margin-top: -4.5px;
  border-radius: 50%;
  background: var(--ink-700);
  border: 1px solid var(--line);
  transition: background 160ms ease, border-color 160ms ease;
}

.page-about .axis-node:hover .axis-dot {
  background: var(--cyan);
  border-color: var(--cyan);
  box-shadow: 0 0 0 4px rgba(53, 230, 210, 0.14);
}

.page-about .axis-ver {
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  color: var(--text);
}

.page-about .axis-tag {
  font-size: 12px;
  color: var(--text-3);
}

.page-about .timeline-panels {
  display: grid;
  gap: 16px;
}

.page-about .timeline-panel {
  padding: clamp(18px, 3vw, 26px);
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-radius: var(--r);
}

.page-about .ver-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 14px;
  margin-bottom: 10px;
}

.page-about .ver-code {
  padding: 2px 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.06em;
  color: var(--cyan);
  border: 1px solid var(--line);
  border-radius: 2px;
}

.page-about .ver-title {
  margin: 0;
  font-size: 18px;
  font-weight: 700;
  line-height: 1.4;
  letter-spacing: -0.01em;
}

.page-about .ver-text {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--text-2);
}

@media (min-width: 960px) {
  .page-about .timeline {
    grid-template-columns: 4fr 8fr;
  }

  .page-about .timeline-axis {
    position: sticky;
    top: calc(var(--header-h) + 24px);
  }
}

/* ---------- 共建生态 ---------- */
.page-about .co-build {
  position: relative;
  overflow: hidden;
  margin-top: clamp(44px, 6vw, 76px);
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-radius: var(--r);
}

.page-about .co-build-bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  max-width: 100%;
  object-fit: cover;
  opacity: 0.2;
  pointer-events: none;
}

.page-about .co-build-inner {
  position: relative;
  padding: clamp(24px, 4vw, 46px);
}

.page-about .co-build-kicker {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--amber);
}

.page-about .co-build-title {
  margin: 0 0 14px;
  font-size: clamp(22px, 3.4vw, 32px);
  font-weight: 900;
  line-height: 1.2;
  letter-spacing: -0.01em;
  font-stretch: 95%;
}

.page-about .co-build-text {
  max-width: 42em;
  margin: 0 0 22px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--text-2);
}

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

.page-about .build-item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 4px 10px;
  align-items: center;
  padding: 12px 14px;
  background: rgba(5, 11, 22, 0.55);
  border: 1px solid var(--line);
  border-radius: var(--r);
}

.page-about .build-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
}

.page-about .build-dot--ochre {
  background: var(--ochre);
}

.page-about .build-dot--violet {
  background: var(--violet);
}

.page-about .build-dot--jade {
  background: var(--jade);
}

.page-about .build-name {
  font-size: 15px;
  font-weight: 700;
}

.page-about .build-desc {
  grid-column: 2 / -1;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-2);
}

.page-about .co-build-foot {
  max-width: 44em;
  margin: 22px 0 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text-2);
}

.page-about .co-build-foot a,
.page-about .cta-desc a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 230, 210, 0.35);
}

.page-about .co-build-foot a:hover,
.page-about .cta-desc a:hover {
  border-bottom-color: var(--cyan);
}

@media (min-width: 760px) {
  .page-about .build-list {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-about .build-item {
    grid-template-columns: auto 1fr;
  }
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  display: grid;
  gap: 20px;
  margin-top: clamp(32px, 4vw, 52px);
  padding: clamp(20px, 3vw, 32px);
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-left: 2px solid var(--amber);
  border-radius: var(--r);
}

.page-about .cta-title {
  margin: 0 0 10px;
  font-size: clamp(20px, 2.8vw, 26px);
  font-weight: 900;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.page-about .cta-desc {
  max-width: 42em;
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text-2);
}

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

@media (min-width: 820px) {
  .page-about .about-cta {
    grid-template-columns: 1fr auto;
    align-items: center;
  }
}