.page-about {
  --about-rail: clamp(1px, 0.16vw, 2px);
  --about-chapter-gap: clamp(56px, 8vw, 104px);
  --about-read: 34em;
  background: var(--void);
  color: var(--silver);
  overflow-x: clip;
}

.page-about .breadcrumb {
  padding-top: clamp(18px, 3vw, 34px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding-block: clamp(34px, 5vw, 66px) clamp(32px, 4.5vw, 56px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: -12% -14% auto -14%;
  height: min(640px, 92vh);
  background:
    radial-gradient(circle at 76% 20%, rgba(142, 124, 255, 0.22), transparent 56%),
    radial-gradient(circle at 12% 76%, rgba(255, 79, 163, 0.12), transparent 62%);
  pointer-events: none;
  z-index: 0;
}

.page-about .about-hero > .container {
  position: relative;
  z-index: 1;
}

.page-about .about-title {
  margin: clamp(14px, 2.6vw, 26px) 0 0;
  font-size: clamp(36px, 8vw, 92px);
  font-weight: 200;
  line-height: 1.08;
  letter-spacing: -0.01em;
  color: var(--silver);
  max-width: 15ch;
}

.page-about .about-lede {
  margin: clamp(18px, 2.8vw, 30px) 0 0;
  max-width: var(--about-read);
  font-size: 17px;
  line-height: 1.9;
  color: var(--mist);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1px;
  margin: clamp(30px, 4.6vw, 52px) 0 0;
  padding: 0;
  list-style: none;
  background: var(--orbit);
  border: 2px solid var(--orbit);
}

.page-about .hero-stats > li {
  background: var(--panel);
  padding: clamp(16px, 2.4vw, 26px);
}

.page-about .hero-stat__val {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(26px, 3.4vw, 38px);
  font-weight: 500;
  line-height: 1.05;
  color: var(--fluor);
}

.page-about .hero-stat__label {
  display: block;
  margin-top: 10px;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--mist);
}

/* ---------- 章节骨架 ---------- */
.page-about .chapter {
  display: grid;
  gap: clamp(20px, 3vw, 40px);
  padding-block: var(--about-chapter-gap);
  border-top: 1px solid var(--orbit);
}

.page-about .chapter-head {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.page-about .chapter-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(52px, 9vw, 108px);
  font-weight: 200;
  line-height: 0.86;
  letter-spacing: -0.02em;
  color: var(--violet-deep);
}

.page-about .chapter-title {
  margin: 0;
  font-size: clamp(24px, 3.2vw, 36px);
  font-weight: 300;
  line-height: 1.28;
  letter-spacing: 0.015em;
  color: var(--silver);
}

.page-about .chapter-body {
  min-width: 0;
}

.page-about .chapter-body > p {
  margin: 0 0 1.1em;
  max-width: var(--about-read);
  font-size: 17px;
  line-height: 1.9;
  color: var(--silver);
}

.page-about .sub-title {
  margin: clamp(34px, 5vw, 52px) 0 14px;
  font-size: clamp(18px, 2.2vw, 22px);
  font-weight: 400;
  letter-spacing: 0.02em;
  color: var(--magenta);
}

/* ---------- 图片 ---------- */
.page-about .figure {
  margin: clamp(28px, 4vw, 44px) 0 0;
}

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

.page-about .figure__caption {
  margin-top: 12px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .figure--tall {
  max-width: 460px;
}

/* ---------- 阶段展开组 ---------- */
.page-about .stage-stack {
  margin-top: clamp(24px, 3.6vw, 40px);
  border-bottom: 1px solid var(--orbit);
}

.page-about .stage {
  border-top: 1px solid var(--orbit);
  background: transparent;
  transition: background 240ms var(--ease);
}

.page-about .stage[open] {
  background: var(--panel);
  border-top-color: var(--violet);
}

.page-about .stage__summary {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 18px 6px;
  cursor: pointer;
  list-style: none;
}

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

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

.page-about .stage[open] .stage__summary::after {
  content: "–";
  color: var(--fluor);
}

.page-about .stage__summary:focus-visible {
  outline: 2px solid var(--violet);
  outline-offset: 2px;
}

.page-about .stage__idx {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--magenta);
  white-space: nowrap;
}

.page-about .stage__name {
  font-size: clamp(17px, 2.1vw, 21px);
  font-weight: 400;
  letter-spacing: 0.02em;
  color: var(--silver);
}

.page-about .stage__body {
  padding: 0 6px 22px;
}

.page-about .stage__body p {
  margin: 0;
  max-width: var(--about-read);
  font-size: 16px;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 奶油纸白条带 ---------- */
.page-about .paper-band {
  position: relative;
  background: var(--paper);
  color: var(--ink);
  border: 2px solid var(--ink);
  box-shadow: 8px 8px 0 0 var(--violet-deep);
  padding: clamp(24px, 4vw, 44px);
  margin-block: clamp(36px, 5vw, 64px);
}

.page-about .eyebrow--ink {
  color: #6B6355;
  margin: 0;
}

.page-about .paper-band__title {
  margin: 10px 0 0;
  font-size: clamp(22px, 3vw, 34px);
  font-weight: 300;
  line-height: 1.3;
  letter-spacing: 0.01em;
  color: var(--ink);
}

.page-about .stage-rail {
  margin-top: clamp(20px, 3vw, 34px);
}

.page-about .stage-rail__line {
  display: block;
  width: 100%;
  height: auto;
  max-height: 120px;
}

.page-about .stage-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px 16px;
  margin: 14px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .stage-list__item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  letter-spacing: 0.08em;
  color: #4A4438;
}

.page-about .stage-list__dot {
  flex: none;
  width: 8px;
  height: 8px;
  border-radius: 50%;
}

.page-about .stage-list__dot--a { background: #1B2547; }
.page-about .stage-list__dot--b { background: #8E7CFF; }
.page-about .stage-list__dot--c { background: #FF4FA3; }
.page-about .stage-list__dot--d { background: #1FA98A; }

.page-about .paper-band__figures {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: clamp(18px, 3vw, 32px);
  margin: clamp(20px, 3vw, 32px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .paper-band__fig {
  border-top: 2px solid var(--ink);
  padding-top: 12px;
}

.page-about .paper-band__fig-val {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(20px, 2.6vw, 28px);
  font-weight: 500;
  line-height: 1.1;
  color: var(--ink);
}

.page-about .paper-band__fig-label {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.6;
  color: #5C5547;
}

/* ---------- 编号示例 ---------- */
.page-about .codex {
  display: grid;
  gap: 2px;
  margin: clamp(24px, 3.6vw, 38px) 0 0;
  padding: 0;
  list-style: none;
  background: var(--orbit);
  border: 2px solid var(--orbit);
}

.page-about .codex__item {
  display: grid;
  gap: 6px 20px;
  background: var(--panel);
  padding: clamp(16px, 2.4vw, 22px);
}

.page-about .codex__id {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(20px, 2.6vw, 26px);
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--fluor);
}

.page-about .codex__desc {
  font-size: 15px;
  line-height: 1.75;
  color: var(--mist);
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 2px;
  margin: clamp(24px, 3.6vw, 38px) 0 0;
  padding: 0;
  list-style: none;
  background: var(--orbit);
  border: 2px solid var(--orbit);
}

.page-about .team-card {
  background: var(--panel);
  padding: clamp(18px, 2.4vw, 26px);
}

.page-about .team-card__num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(24px, 3.2vw, 34px);
  font-weight: 300;
  line-height: 1;
  color: var(--magenta);
}

.page-about .team-card__name {
  margin: 14px 0 8px;
  font-size: 16px;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--silver);
}

.page-about .team-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist);
}

/* ---------- 双人校验 ---------- */
.page-about .check-duo {
  display: grid;
  gap: 2px;
  margin-top: clamp(22px, 3.4vw, 34px);
  background: var(--orbit);
  border: 2px solid var(--orbit);
}

.page-about .check-col {
  background: var(--panel);
  padding: clamp(20px, 3vw, 28px);
}

.page-about .check-col__title {
  margin: 0 0 16px;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.22em;
  color: var(--magenta);
}

.page-about .check-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .check-list li {
  position: relative;
  padding-left: 26px;
  margin-bottom: 12px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--silver);
}

.page-about .check-list li:last-child {
  margin-bottom: 0;
}

.page-about .check-list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  top: 0;
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--fluor);
}

/* ---------- 覆盖范围 ---------- */
.page-about .reach-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: clamp(18px, 2.6vw, 30px);
  margin: clamp(24px, 3.6vw, 38px) 0 clamp(24px, 3.6vw, 38px);
}

.page-about .reach-item {
  border-left: 2px solid var(--violet);
  padding-left: 16px;
}

.page-about .reach-item__val {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(30px, 4vw, 46px);
  font-weight: 300;
  line-height: 1;
  color: var(--silver);
}

.page-about .reach-item__val--fluor {
  color: var(--fluor);
}

.page-about .reach-item__val--mist {
  color: var(--violet);
}

.page-about .reach-item__unit {
  display: inline-block;
  margin-top: 8px;
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--mist);
}

.page-about .reach-item__label {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--mist);
}

/* ---------- 归档数字条 ---------- */
.page-about .archive-strip {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 2px;
  margin-top: clamp(24px, 3.6vw, 38px);
  background: var(--orbit);
  border: 2px solid var(--orbit);
}

.page-about .archive-cell {
  background: var(--panel);
  padding: clamp(18px, 2.6vw, 26px);
}

.page-about .archive-cell__val {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(28px, 3.6vw, 42px);
  font-weight: 400;
  line-height: 1;
  color: var(--silver);
}

.page-about .archive-cell__unit {
  display: inline-block;
  margin-top: 8px;
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--mist);
}

.page-about .archive-cell__label {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--mist);
}

.page-about .archive-cell--amber .archive-cell__val {
  color: var(--amber);
}

/* ---------- 承诺清单 ---------- */
.page-about .pledge-list {
  display: grid;
  gap: 2px;
  margin: clamp(18px, 2.6vw, 28px) 0 0;
  padding: 0;
  list-style: none;
  background: var(--orbit);
  border: 2px solid var(--orbit);
}

.page-about .pledge-list > li {
  background: var(--panel);
  padding: clamp(18px, 2.6vw, 26px);
}

.page-about .pledge-list__title {
  margin: 0 0 10px;
  font-size: 16px;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--silver);
}

.page-about .pledge-list > li p {
  margin: 0;
  max-width: var(--about-read);
  font-size: 15px;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 结尾入口 ---------- */
.page-about .about-cta {
  margin-top: clamp(28px, 4vw, 44px);
  border-top: 1px solid var(--orbit);
  padding-top: clamp(22px, 3vw, 32px);
}

.page-about .about-cta__text {
  margin: 0 0 20px;
  max-width: var(--about-read);
  font-size: 17px;
  line-height: 1.85;
  color: var(--silver);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.page-about .about-cta__aux {
  margin: 20px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-cta__aux .link-more {
  margin-left: 4px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 700px) {
  .page-about .check-duo {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .page-about .codex__item {
    grid-template-columns: minmax(120px, 180px) minmax(0, 1fr);
    align-items: baseline;
  }
}

@media (min-width: 900px) {
  .page-about .chapter {
    grid-template-columns: minmax(180px, 4fr) minmax(0, 7fr);
    gap: clamp(32px, 5vw, 76px);
  }

  .page-about .chapter-head {
    position: sticky;
    top: 108px;
    align-self: start;
  }

  .page-about .figure--tall {
    margin-top: clamp(30px, 4vw, 44px);
    margin-left: auto;
    margin-right: auto;
  }
}

@media (min-width: 1100px) {
  .page-about .about-title {
    max-width: 14ch;
  }

  .page-about .stage__summary {
    padding: 20px 8px;
  }
}

@media (max-width: 480px) {
  .page-about .about-cta__actions {
    flex-direction: column;
    align-items: stretch;
  }

  .page-about .about-cta__actions .btn {
    text-align: center;
  }

  .page-about .paper-band {
    box-shadow: 5px 5px 0 0 var(--violet-deep);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .stage {
    transition: none;
  }
}