.page-about {
  --about-rail-w: 13.5rem;
  --about-node: 11px;
}

/* 首屏 */
.page-about .about-hero {
  padding-top: clamp(2rem, 6vw, 3.75rem);
}

.page-about .about-hero__inner {
  display: grid;
  gap: 1rem;
}

.page-about .about-hero .breadcrumbs {
  margin-bottom: 0.25rem;
}

.page-about .about-hero__eyebrow {
  color: var(--accent-2);
  margin: 0;
}

.page-about .about-hero__title {
  margin: 0;
  max-width: 20ch;
}

.page-about .about-hero__lede {
  margin: 0;
  max-width: 44ch;
  color: var(--text);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(1.5rem, 4vw, 2.5rem) 0 0;
  padding: 1px;
  border: 1px solid var(--line);
  background: var(--line);
  list-style: none;
}

.page-about .about-facts__cell {
  background: var(--surface);
  padding: 0.85rem 1rem;
  min-width: 0;
}

.page-about .about-facts dt {
  color: var(--muted);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.page-about .about-facts dd {
  margin: 0.4rem 0 0;
  color: var(--text);
  font-size: 1.0625rem;
  overflow-wrap: anywhere;
}

/* 首图 */
.page-about .about-hero__media {
  margin: clamp(2rem, 5vw, 3rem) 0 0;
  padding: 0 var(--gutter);
}

.page-about .about-hero__frame {
  aspect-ratio: 16 / 9;
  margin: 0;
  border: 1px solid var(--line);
}

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

.page-about .about-hero__media .media__caption {
  max-width: 60ch;
}

/* 主体两栏 */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(2rem, 5vw, 3rem);
  padding-top: clamp(2.5rem, 6vw, 4.5rem);
  padding-bottom: clamp(3rem, 7vw, 5rem);
}

.page-about .about-rail {
  border-top: 2px solid var(--line);
  padding-top: 1rem;
}

.page-about .about-rail__list {
  list-style: none;
  margin: 1rem 0 0;
  padding: 0;
  display: grid;
  gap: 0.125rem;
  border-left: 1px solid var(--line);
}

.page-about .about-rail__link {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  margin-left: -1px;
  padding: 0.5rem 0 0.5rem 0.9rem;
  border-left: 2px solid transparent;
  color: var(--muted);
  font-size: 0.9375rem;
  text-decoration: none;
  transition: color 240ms var(--ease), border-color 240ms var(--ease);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--text);
  border-left-color: var(--accent-2);
}

.page-about .about-rail__no {
  color: var(--accent);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
}

.page-about .about-rail__note {
  margin: 1.25rem 0 0;
}

/* 章节 */
.page-about .about-section {
  padding: clamp(2rem, 5vw, 3rem) 0;
  border-top: 1px solid var(--line);
}

.page-about .about-section:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-section__head {
  display: flex;
  align-items: baseline;
  gap: 0.85rem;
  margin-bottom: 1.25rem;
}

.page-about .about-section__title {
  margin: 0;
  font-size: clamp(1.375rem, 3.4vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.25;
  color: var(--text);
}

.page-about .about-section .prose + .prose {
  margin-top: 0.9rem;
}

/* 三个能力点 */
.page-about .about-points {
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 1px;
  display: grid;
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.page-about .about-points li {
  background: var(--bg-alt);
  padding: 1.05rem 1.15rem;
  display: grid;
  gap: 0.45rem;
}

.page-about .about-points__k {
  color: var(--accent-2);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
}

.page-about .about-points__v {
  margin: 0;
  color: var(--text);
  font-size: 0.9375rem;
  line-height: 1.7;
  max-width: 42ch;
}

.page-about .about-points__v a {
  color: var(--accent-2);
  text-underline-offset: 3px;
}

/* 版本时间线 */
.page-about .about-versions {
  display: grid;
  gap: clamp(1.75rem, 4vw, 2.5rem);
  margin-top: 1.75rem;
}

.page-about .ver-list {
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
}

.page-about .ver-list::before {
  content: "";
  position: absolute;
  left: calc(var(--about-node) / 2 - 0.5px);
  top: 0.5rem;
  bottom: 1rem;
  width: 1px;
  background: var(--line);
}

.page-about .ver-item {
  position: relative;
  padding: 0 0 1.85rem calc(var(--about-node) + 1.1rem);
}

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

.page-about .ver-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.3rem;
  width: var(--about-node);
  height: var(--about-node);
  background: var(--bg);
  border: 2px solid var(--line);
}

.page-about .ver-item--now::before {
  background: var(--accent);
  border-color: var(--accent);
  box-shadow: 0 0 0 4px rgba(200, 255, 60, 0.14);
}

.page-about .ver-tag {
  margin: 0;
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  color: var(--muted);
}

.page-about .ver-item--now .ver-tag {
  color: var(--accent);
}

.page-about .ver-title {
  margin: 0.35rem 0 0.45rem;
  font-size: 1.125rem;
  font-weight: 700;
  line-height: 1.35;
  color: var(--text);
}

.page-about .ver-text {
  margin: 0;
  color: var(--muted);
  font-size: 0.9375rem;
  line-height: 1.75;
  max-width: 44ch;
}

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

.page-about .about-versions__media .media__frame {
  margin: 0;
  border: 1px solid var(--line);
}

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

/* 手机场景 */
.page-about .scene-list {
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 0;
  display: grid;
  gap: 1rem;
}

.page-about .scene-item {
  border: 1px solid var(--line);
  background: var(--surface);
  padding: 1.2rem 1.25rem;
  transition: border-color 240ms var(--ease), box-shadow 240ms var(--ease),
    transform 240ms var(--ease);
}

.page-about .scene-item:hover {
  border-color: var(--accent);
  box-shadow: 6px 6px 0 0 rgba(0, 0, 0, 0.55);
  transform: translate(-2px, -2px);
}

.page-about .scene-item__idx {
  margin: 0;
  color: var(--accent-2);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
}

.page-about .scene-item__title {
  margin: 0.5rem 0 0.5rem;
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.4;
}

.page-about .scene-item__text {
  margin: 0;
  color: var(--muted);
  font-size: 0.9375rem;
  line-height: 1.75;
  max-width: 44ch;
}

/* 三道流程 */
.page-about .flow__steps {
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.page-about .flow__steps > li {
  background: var(--bg);
  padding: 1.15rem 1.2rem;
  border-left: 2px solid var(--line);
}

.page-about .flow__steps > li:first-child {
  border-left-color: var(--accent);
}

.page-about .flow__step-no {
  margin: 0;
  color: var(--muted);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
}

.page-about .flow__step-title {
  margin: 0.45rem 0 0.5rem;
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--text);
}

.page-about .flow__step-text {
  margin: 0;
  color: var(--muted);
  font-size: 0.9375rem;
  line-height: 1.75;
}

.page-about .about-data__media {
  margin: 1.75rem 0 0;
}

.page-about .about-data__media .media__frame {
  margin: 0;
  border: 1px solid var(--line);
}

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

/* 口径台账 */
.page-about .meta-ledger,
.page-about .team-ledger,
.page-about .legal-ledger {
  margin: 1.75rem 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .meta-ledger__row,
.page-about .team-ledger__row,
.page-about .legal-ledger__row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.35rem 1.5rem;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--line);
}

.page-about .meta-ledger dt,
.page-about .team-ledger dt,
.page-about .legal-ledger dt {
  color: var(--muted);
  font-size: 0.8125rem;
  letter-spacing: 0.06em;
  flex: 0 0 auto;
}

.page-about .meta-ledger dd,
.page-about .legal-ledger dd {
  margin: 0;
  color: var(--text);
  font-size: 0.9375rem;
  text-align: right;
  flex: 1 1 auto;
  min-width: 0;
  overflow-wrap: anywhere;
}

.page-about .team-ledger dd {
  margin: 0;
  flex: 1 1 22ch;
  color: var(--text);
  font-size: 0.9375rem;
  line-height: 1.7;
  text-align: left;
}

.page-about .team-ledger dt {
  color: var(--accent-2);
}

/* 团队规模数字 */
.page-about .about-team__stat {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin: 1.75rem 0 1.5rem;
  padding: 1rem 0;
  border-top: 2px solid var(--line);
  border-bottom: 2px solid var(--line);
}

.page-about .about-team__num {
  font-size: clamp(2.75rem, 9vw, 4.25rem);
  font-weight: 500;
  line-height: 1;
  color: var(--accent);
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}

.page-about .about-team__unit {
  color: var(--muted);
  font-size: 0.875rem;
  letter-spacing: 0.04em;
}

.page-about .about-section .prose a {
  color: var(--accent-2);
  text-underline-offset: 3px;
}

/* 桌面端 */
@media (min-width: 720px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about .scene-item:nth-child(2) {
    margin-left: 6%;
  }

  .page-about .scene-item:nth-child(3) {
    margin-left: 12%;
  }
}

@media (min-width: 960px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(2.5rem, 5vw, 4.5rem);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 1.75rem);
    border-top-width: 2px;
  }

  .page-about .about-versions {
    grid-template-columns: minmax(0, 1fr) minmax(0, 20rem);
    gap: clamp(2rem, 4vw, 3rem);
  }

  .page-about .about-hero__media {
    padding-left: 0;
    padding-right: 0;
  }

  .page-about .about-hero__frame {
    max-width: var(--shell);
    margin: 0 auto;
  }
}

@media (min-width: 1200px) {
  .page-about .about-hero__title {
    max-width: 24ch;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .scene-item,
  .page-about .about-rail__link {
    transition: none;
  }

  .page-about .scene-item:hover {
    transform: none;
  }
}