.page-about {
  --about-rule: 1px solid var(--ink-line);
  --about-pad: clamp(18px, 2.6vw, 26px);
  padding-bottom: 84px;
}

/* ---------- 页头 ---------- */
.page-about .about-head {
  padding-top: 26px;
  padding-bottom: 6px;
}

.page-about .about-head .eyebrow {
  margin: 0 0 14px;
}

.page-about .about-head__metrics,
.page-about .about-scale {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--ink-line);
  border: 1px solid var(--ink-line);
}

.page-about .about-head__metrics > li,
.page-about .about-scale > li {
  background: var(--space-navy);
  padding: 16px 18px 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-width: 0;
}

.page-about .about-metric__value {
  font-size: var(--step-5);
  line-height: 1;
  color: var(--cyan);
  letter-spacing: -0.01em;
}

.page-about .about-metric__unit {
  font-size: var(--step-3);
  margin-left: 2px;
}

.page-about .about-metric__label {
  font-size: var(--step-1);
  color: var(--muted);
  line-height: 1.5;
}

/* ---------- 主框架：目录 + 正文 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 34px;
  margin-top: 46px;
}

.page-about .about-toc {
  border-top: var(--about-rule);
  border-bottom: var(--about-rule);
  padding: 18px 0 14px;
}

.page-about .about-toc__title {
  margin: 0 0 12px;
  font-family: var(--font-serif);
  font-size: var(--step-1);
  letter-spacing: 0.32em;
  text-transform: uppercase;
  color: var(--muted-deep);
}

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

.page-about .about-toc__link {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 10px 2px;
  font-size: var(--step-2);
  color: var(--text-soft);
  text-decoration: none;
  border-bottom: 1px dashed var(--ink-line);
  transition: color 0.2s var(--ease), padding-left 0.2s var(--ease);
}

.page-about .about-toc__list li:last-child .about-toc__link {
  border-bottom: 0;
}

.page-about .about-toc__link:hover,
.page-about .about-toc__link:focus-visible {
  color: var(--cyan);
  padding-left: 6px;
}

.page-about .about-toc__num {
  font-size: var(--step-1);
  color: var(--cyan);
  letter-spacing: 0.06em;
}

.page-about .about-toc__note {
  margin: 16px 0 0;
  font-size: var(--step-1);
  line-height: 1.65;
  color: var(--muted-deep);
  border-left: 2px solid var(--ink-line);
  padding-left: 12px;
}

/* ---------- 章节 ---------- */
.page-about .about-section {
  scroll-margin-top: 96px;
}

.page-about .about-section + .about-section {
  margin-top: 68px;
  padding-top: 40px;
  border-top: var(--about-rule);
}

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

.page-about .about-section .lead {
  max-width: 62ch;
  color: var(--text-soft);
}

.page-about .about-subtitle {
  margin: 26px 0 8px;
  font-family: var(--font-display);
  font-size: var(--step-4);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--text);
}

.page-about .about-subtitle--spaced {
  margin-top: 40px;
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  position: relative;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan) 0%, var(--ink-line) 42%, var(--ink-line) 100%);
}

.page-about .about-timeline__item {
  position: relative;
  padding: 0 0 28px 34px;
}

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

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: 1px;
  top: 5px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--deep-void);
  border: 2px solid var(--cyan);
}

.page-about .about-timeline__mark {
  display: inline-block;
  font-size: var(--step-1);
  letter-spacing: 0.08em;
  color: var(--cyan);
}

.page-about .about-timeline__item h3 {
  margin: 6px 0 7px;
  font-family: var(--font-display);
  font-size: var(--step-4);
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: var(--text);
}

.page-about .about-timeline__item p {
  margin: 0;
  max-width: 66ch;
  color: var(--text-soft);
}

/* ---------- 旁注 ---------- */
.page-about .aside-note {
  margin: 26px 0 0;
  padding: 14px 16px;
  border-left: 2px solid var(--ink-line);
  background: rgba(18, 41, 79, 0.55);
  font-size: var(--step-2);
  line-height: 1.7;
  color: var(--text-soft);
}

.page-about .aside-note__title {
  display: block;
  margin-bottom: 4px;
  font-family: var(--font-serif);
  font-size: var(--step-1);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted-deep);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 34px 0 0;
}

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

.page-about .about-figure .media-frame__caption {
  font-size: var(--step-1);
  color: var(--muted);
}

.page-about .about-grid-2 {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
  margin-top: 8px;
}

.page-about .about-copy p {
  margin: 0 0 4px;
  max-width: 66ch;
  color: var(--text-soft);
}

/* ---------- 折叠口径 ---------- */
.page-about .about-folds {
  margin-top: 26px;
  border-top: var(--about-rule);
}

.page-about .about-folds .fold {
  border-bottom: var(--about-rule);
}

.page-about .about-folds .fold__summary {
  font-size: var(--step-3);
  font-weight: 600;
  padding: 16px 0;
  color: var(--text);
}

.page-about .about-folds .fold__summary:hover {
  color: var(--cyan);
}

.page-about .about-folds .fold__body {
  padding-bottom: 18px;
  color: var(--text-soft);
}

.page-about .about-folds .fold__body p {
  margin: 0 0 10px;
  max-width: 68ch;
}

.page-about .about-exception {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  padding: 11px 14px;
  border-left: 2px solid var(--orange);
  background: rgba(255, 107, 53, 0.07);
  font-size: var(--step-2);
  line-height: 1.6;
}

.page-about .about-exception .chip {
  flex: 0 0 auto;
  margin-top: 1px;
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--ink-line);
  border: 1px solid var(--ink-line);
}

.page-about .about-team > li {
  background: var(--navy-raised);
  padding: var(--about-pad);
  position: relative;
  overflow: hidden;
}

.page-about .about-team > li::after {
  content: "";
  position: absolute;
  right: -30px;
  top: -30px;
  width: 62px;
  height: 62px;
  background: linear-gradient(135deg, rgba(0, 229, 255, 0.16), transparent 68%);
  transform: rotate(45deg);
}

.page-about .about-team__num {
  display: block;
  font-size: var(--step-6);
  line-height: 1;
  color: var(--cyan);
}

.page-about .about-team__role {
  display: block;
  margin-top: 10px;
  font-size: var(--step-3);
  font-weight: 700;
  color: var(--text);
}

.page-about .about-team__desc {
  margin: 6px 0 0;
  font-size: var(--step-2);
  line-height: 1.65;
  color: var(--muted);
}

/* ---------- 版本横向轨道 ---------- */
.page-about .about-track {
  display: flex;
  gap: 14px;
  margin-top: 26px;
  padding: 4px 2px 18px;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  scrollbar-width: thin;
  scrollbar-color: var(--ink-line) transparent;
}

.page-about .about-ver {
  flex: 0 0 min(276px, 78vw);
  scroll-snap-align: start;
  padding: 18px 18px 20px;
  background: linear-gradient(180deg, var(--navy-raised) 0%, var(--space-navy) 100%);
  box-shadow: inset 0 0 0 1px var(--ink-line);
  clip-path: polygon(0 0, calc(100% - 16px) 0, 100% 16px, 100% 100%, 0 100%);
  transition: transform 0.35s var(--ease), box-shadow 0.35s var(--ease);
}

.page-about .about-ver:hover {
  transform: translateY(-4px);
  box-shadow: inset 0 0 0 1px var(--cyan);
}

.page-about .about-ver--current {
  box-shadow: inset 0 0 0 1px var(--cyan);
  background: linear-gradient(180deg, rgba(0, 229, 255, 0.1) 0%, var(--space-navy) 100%);
}

.page-about .about-ver__summary {
  list-style: none;
  cursor: pointer;
  display: grid;
  gap: 7px;
}

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

.page-about .about-ver__gen {
  font-size: var(--step-1);
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .about-ver__name {
  font-family: var(--font-display);
  font-size: var(--step-4);
  font-weight: 600;
  line-height: 1.25;
  color: var(--text);
}

.page-about .about-ver__cue {
  font-size: var(--step-1);
  color: var(--muted-deep);
}

.page-about .about-ver[open] .about-ver__cue {
  color: var(--cyan-soft);
}

.page-about .about-ver__body {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px dashed var(--ink-line);
  font-size: var(--step-2);
  line-height: 1.7;
  color: var(--text-soft);
}

.page-about .about-ver__body p {
  margin: 0;
}

/* ---------- 覆盖与节奏 ---------- */
.page-about .about-cadence {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
}

.page-about .about-cadence li {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 13px 0;
  border-top: 1px dashed var(--ink-line);
  font-size: var(--step-2);
  color: var(--text-soft);
}

.page-about .about-cadence li:last-child {
  border-bottom: 1px dashed var(--ink-line);
}

.page-about .about-cadence__key {
  font-size: var(--step-1);
  letter-spacing: 0.08em;
  color: var(--cyan);
}

/* ---------- 收束区块 ---------- */
.page-about .about-outro {
  margin-top: 72px;
  padding: var(--about-pad);
  background: linear-gradient(135deg, rgba(0, 229, 255, 0.09) 0%, rgba(11, 27, 58, 0.9) 46%, var(--space-navy) 100%);
  border: 1px solid var(--ink-line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 22px), calc(100% - 22px) 100%, 0 100%);
}

.page-about .about-outro .eyebrow {
  margin: 0 0 10px;
}

.page-about .about-outro__title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-size: var(--step-5);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--text);
}

.page-about .about-outro__text {
  margin: 0;
  max-width: 64ch;
  color: var(--text-soft);
}

.page-about .about-outro__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .about-head__metrics,
  .page-about .about-scale {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about .about-cadence li {
    grid-template-columns: 132px minmax(0, 1fr);
    align-items: baseline;
    gap: 18px;
  }
}

@media (min-width: 980px) {
  .page-about {
    padding-bottom: 120px;
  }

  .page-about .about-head {
    padding-top: 40px;
  }

  .page-about .about-shell {
    grid-template-columns: 236px minmax(0, 1fr);
    gap: 58px;
    margin-top: 58px;
  }

  .page-about .about-toc {
    position: sticky;
    top: 104px;
    border-bottom: 0;
  }

  .page-about .about-grid-2 {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: 34px;
    align-items: start;
  }

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

  .page-about .about-section + .about-section {
    margin-top: 78px;
    padding-top: 48px;
  }
}

@media (min-width: 1180px) {
  .page-about .about-toc {
    padding-right: 12px;
  }

  .page-about .about-ver {
    flex-basis: 262px;
  }
}

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

  .page-about .about-ver:hover {
    transform: none;
  }
}