.page-about {
  --about-space: clamp(48px, 7vw, 96px);
  --about-gap: clamp(24px, 4vw, 48px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-block: clamp(24px, 4vw, 48px) clamp(48px, 7vw, 88px);
}

.page-about .about-hero .breadcrumb {
  margin-bottom: clamp(24px, 4vw, 44px);
}

.page-about .about-hero__split {
  display: grid;
  gap: var(--about-gap);
  align-items: start;
}

.page-about .about-hero__text h1 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 6vw, 3.5rem);
  line-height: 1.14;
  letter-spacing: -0.01em;
  color: var(--c-paper);
  margin: 12px 0 0;
  max-width: 20ch;
}

.page-about .about-hero__lead {
  margin-top: 20px;
  max-width: 42ch;
  font-size: var(--fs-body);
  line-height: 1.8;
  color: var(--c-body);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.page-about .about-hero__panel {
  position: relative;
  padding: clamp(22px, 3vw, 30px);
  background: var(--c-ink-lift);
}

.page-about .about-hero__panel .stamp {
  position: absolute;
  top: -12px;
  right: 16px;
}

.page-about .about-hero__panel-title {
  font-family: var(--font-display);
  font-size: var(--fs-sub);
  color: var(--c-paper);
  margin: 6px 0 18px;
  letter-spacing: 0.01em;
}

.page-about .about-legend {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.page-about .about-legend__item {
  display: grid;
  grid-template-columns: 14px minmax(0, 1fr) auto;
  align-items: center;
  gap: 12px;
  padding: 11px 12px;
  border: 1px solid var(--c-line);
  background: rgba(255, 255, 255, 0.02);
  transition: transform 200ms var(--ease), background 200ms var(--ease), border-color 200ms var(--ease);
}

.page-about .about-legend__item:hover,
.page-about .about-legend__item:focus-within {
  transform: translateX(5px);
  background: rgba(255, 255, 255, 0.06);
  border-color: var(--c-muted);
}

.page-about .about-legend__dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  display: block;
}

.page-about .about-legend__item--spring .about-legend__dot { background: var(--c-spring); }
.page-about .about-legend__item--summer .about-legend__dot { background: var(--c-summer); }
.page-about .about-legend__item--autumn .about-legend__dot { background: var(--c-autumn); }
.page-about .about-legend__item--winter .about-legend__dot { background: var(--c-winter); }

.page-about .about-legend__name {
  font-size: var(--fs-aux);
  color: var(--c-paper);
  letter-spacing: 0.04em;
}

.page-about .about-legend__desc {
  font-size: var(--fs-annotation);
  color: var(--c-muted);
}

.page-about .about-hero__panel .annotation-vertical {
  position: absolute;
  left: -22px;
  bottom: 24px;
  color: var(--c-faint);
}

/* ---------- 章节编号 ---------- */
.page-about .section-index {
  font-family: var(--font-mono);
  font-size: var(--fs-aux);
  letter-spacing: 0.22em;
  color: var(--c-muted);
  margin: 0 0 clamp(16px, 2.5vw, 28px);
  padding-bottom: 10px;
  border-bottom: 1px solid var(--c-line);
}

/* ---------- 01 品牌 ---------- */
.page-about .about-brand {
  padding-block: var(--about-space);
}

.page-about .about-brand__grid {
  display: grid;
  gap: var(--about-gap);
}

.page-about .about-brand__body p {
  color: var(--c-body);
}

.page-about .about-pillars {
  list-style: none;
  margin: clamp(36px, 5vw, 64px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--c-line);
  border: 1px solid var(--c-line);
}

.page-about .about-pillars__item {
  background: var(--c-teal);
  padding: clamp(20px, 3vw, 30px);
  display: grid;
  gap: 8px;
  transition: background 220ms var(--ease);
}

.page-about .about-pillars__item:hover {
  background: #123737;
}

.page-about .about-pillars__mark {
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  color: var(--c-spring);
  letter-spacing: 0.2em;
}

.page-about .about-pillars__title {
  font-family: var(--font-display);
  font-size: var(--fs-sub);
  color: var(--c-paper);
  margin: 0;
}

.page-about .about-pillars__desc {
  margin: 0;
  font-size: var(--fs-aux);
  line-height: 1.75;
  color: var(--c-body);
}

/* ---------- 02 业务范围 ---------- */
.page-about .about-scope {
  padding-block: var(--about-space);
}

.page-about .about-scope__head {
  max-width: 46ch;
  margin-bottom: clamp(28px, 4vw, 48px);
}

.page-about .about-scope__flow {
  align-items: start;
}

.page-about .about-scope__main .prose p {
  color: var(--c-body);
}

.page-about .about-scope__links {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  margin-top: 22px;
}

.page-about .about-scope__aside {
  border: 1px solid var(--c-line);
  padding: clamp(20px, 3vw, 28px);
  background: var(--c-ink-lift);
}

.page-about .about-scope__aside-title {
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  letter-spacing: 0.18em;
  color: var(--c-muted);
  margin: 0 0 16px;
}

.page-about .about-sports {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .about-scope__note {
  margin: 18px 0 0;
  font-size: var(--fs-annotation);
  line-height: 1.7;
  color: var(--c-muted);
}

/* ---------- 03 团队 ---------- */
.page-about .about-team {
  padding-block: var(--about-space);
}

.page-about .about-team__head {
  max-width: 48ch;
  margin-bottom: clamp(28px, 4vw, 48px);
}

.page-about .about-team__media {
  margin-bottom: clamp(32px, 5vw, 56px);
}

.page-about .about-roles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--about-gap);
}

.page-about .about-roles__card {
  padding: clamp(22px, 3vw, 32px);
  background: rgba(255, 255, 255, 0.02);
}

.page-about .about-roles__num {
  font-family: var(--font-mono);
  font-size: clamp(2.25rem, 5vw, 3rem);
  line-height: 1;
  color: var(--c-spring);
  margin: 0 0 12px;
  font-variant-numeric: tabular-nums;
}

.page-about .about-roles__name {
  font-family: var(--font-display);
  font-size: var(--fs-sub);
  color: var(--c-paper);
  margin: 0 0 10px;
}

.page-about .about-roles__desc {
  margin: 0;
  font-size: var(--fs-aux);
  line-height: 1.8;
  color: var(--c-body);
}

.page-about .about-team__note {
  margin: clamp(28px, 4vw, 44px) 0 0;
  font-size: var(--fs-aux);
  line-height: 1.8;
  color: var(--c-muted);
  max-width: 52ch;
}

.page-about .about-team__note a {
  color: var(--c-spring);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- 04 版本演进 ---------- */
.page-about .about-versions {
  padding-block: var(--about-space);
}

.page-about .about-versions__head {
  max-width: 50ch;
  margin-bottom: clamp(28px, 4vw, 44px);
}

.page-about .about-versions__media {
  margin-bottom: clamp(32px, 5vw, 56px);
}

.page-about .about-version-tabs__list {
  display: flex;
  gap: 0;
  margin: 0;
  padding: 0;
  overflow-x: auto;
  border-top: 1px solid var(--c-line);
  border-bottom: 1px solid var(--c-line);
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-version-tabs__tab {
  flex: 0 0 auto;
  min-width: 148px;
  padding: 16px 18px;
  background: transparent;
  border: 0;
  border-right: 1px solid var(--c-line);
  color: var(--c-muted);
  font-family: var(--font-body);
  font-size: var(--fs-aux);
  text-align: left;
  cursor: pointer;
  display: grid;
  gap: 6px;
  position: relative;
  transition: color 180ms var(--ease), background 180ms var(--ease);
}

.page-about .about-version-tabs__tab::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  background: var(--c-autumn);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 200ms var(--ease);
}

.page-about .about-version-tabs__tab:hover {
  color: var(--c-paper);
  background: rgba(255, 255, 255, 0.04);
}

.page-about .about-version-tabs__tab[aria-selected="true"] {
  color: var(--c-paper);
  background: rgba(242, 180, 65, 0.08);
}

.page-about .about-version-tabs__tab[aria-selected="true"]::after {
  transform: scaleX(1);
}

.page-about .about-version-tabs__ver {
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  letter-spacing: 0.14em;
  color: var(--c-autumn);
}

.page-about .about-version-tabs__label {
  line-height: 1.5;
}

.page-about .about-version-tabs__panel {
  padding: clamp(24px, 3.5vw, 40px) 0;
  border-bottom: 1px solid var(--c-line-soft);
}

.page-about .about-version-tabs__panel[hidden] {
  display: none;
}

.page-about .about-version-tabs__title {
  font-family: var(--font-display);
  font-size: var(--fs-sub);
  color: var(--c-paper);
  margin: 0 0 12px;
}

.page-about .about-version-tabs__panel p {
  margin: 0;
  max-width: 62ch;
  font-size: var(--fs-body);
  line-height: 1.85;
  color: var(--c-body);
}

.page-about .about-versions__foot {
  margin: clamp(28px, 4vw, 44px) 0 0;
  font-size: var(--fs-aux);
  line-height: 1.8;
  color: var(--c-muted);
  max-width: 56ch;
}

/* ---------- 05 协作生态 ---------- */
.page-about .about-eco {
  padding-block: var(--about-space);
}

.page-about .about-eco__grid {
  display: grid;
  gap: var(--about-gap);
  align-items: start;
}

.page-about .about-eco__body .prose p {
  color: var(--c-body);
}

.page-about .about-eco__stats {
  list-style: none;
  margin: clamp(24px, 3.5vw, 36px) 0 0;
  padding: 0;
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
}

.page-about .about-eco__stats .stat {
  border-left: 2px solid var(--c-line);
  padding-left: 14px;
}

/* ---------- 06 用户规模 ---------- */
.page-about .about-audience {
  padding-block: var(--about-space);
}

.page-about .about-audience__head {
  max-width: 50ch;
  margin-bottom: clamp(28px, 4vw, 48px);
}

.page-about .about-audience__grid {
  display: grid;
  gap: var(--about-gap);
  align-items: start;
}

.page-about .about-regions__title {
  font-family: var(--font-mono);
  font-size: var(--fs-annotation);
  letter-spacing: 0.18em;
  color: var(--c-muted);
  margin: 0 0 18px;
}

.page-about .about-regions__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-regions__row {
  display: grid;
  grid-template-columns: 4.5em minmax(0, 1fr);
  grid-template-areas:
    "name note"
    "bar  bar";
  gap: 6px 12px;
  align-items: center;
}

.page-about .about-regions__name {
  grid-area: name;
  font-size: var(--fs-aux);
  color: var(--c-paper);
}

.page-about .about-regions__note {
  grid-area: note;
  font-size: var(--fs-annotation);
  color: var(--c-muted);
  text-align: right;
}

.page-about .about-regions__bar {
  grid-area: bar;
  display: block;
  height: 10px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--c-line);
  overflow: hidden;
}

.page-about .about-regions__fill {
  display: block;
  height: 100%;
  width: var(--w, 50%);
  background: linear-gradient(90deg, var(--c-winter), var(--c-spring));
  transform-origin: left;
  animation: about-bar-grow 900ms var(--ease) both;
}

@keyframes about-bar-grow {
  from { transform: scaleX(0); }
  to { transform: scaleX(1); }
}

.page-about .about-audience__aside {
  border: 1px solid var(--c-line);
  background: var(--c-ink-lift);
  padding: clamp(22px, 3vw, 32px);
}

.page-about .about-audience__aside-title {
  font-family: var(--font-display);
  font-size: var(--fs-sub);
  color: var(--c-paper);
  margin: 0 0 12px;
}

.page-about .about-audience__aside-text {
  margin: 0;
  font-size: var(--fs-aux);
  line-height: 1.8;
  color: var(--c-body);
}

.page-about .about-scores {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--c-line);
  border: 1px solid var(--c-line);
}

.page-about .about-scores__item {
  background: var(--c-ink);
  padding: 14px 16px;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
}

.page-about .about-scores__label {
  font-size: var(--fs-aux);
  color: var(--c-body);
}

.page-about .about-scores__value {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  color: var(--c-autumn);
  font-variant-numeric: tabular-nums;
}

.page-about .about-scores__value small {
  font-size: var(--fs-annotation);
  color: var(--c-muted);
  margin-left: 2px;
}

.page-about .about-audience__aside-foot {
  margin: 20px 0 0;
  font-size: var(--fs-annotation);
  line-height: 1.75;
  color: var(--c-muted);
}

.page-about .about-audience__aside-foot a {
  color: var(--c-winter);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- 07 反馈入口 ---------- */
.page-about .about-join {
  padding-block: var(--about-space);
}

.page-about .about-join__box {
  border-top: 2px solid var(--c-autumn);
  padding-top: clamp(24px, 3.5vw, 40px);
}

.page-about .about-join__text {
  margin: 18px 0 0;
  max-width: 52ch;
  font-size: var(--fs-body);
  line-height: 1.85;
  color: var(--c-body);
}

.page-about .about-join__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .about-regions__row {
    grid-template-columns: 5em minmax(0, 1fr) auto;
    grid-template-areas: "name bar note";
  }

  .page-about .about-regions__note {
    text-align: right;
    white-space: nowrap;
  }
}

@media (min-width: 960px) {
  .page-about .about-hero__split {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
    align-items: end;
  }

  .page-about .about-hero__panel {
    margin-top: 56px;
  }

  .page-about .about-brand__grid {
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
    align-items: start;
  }

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

  .page-about .about-eco__grid {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
    align-items: center;
  }

  .page-about .about-audience__grid {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
  }
}

@media (min-width: 1200px) {
  .page-about .about-hero__split {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 72px;
  }
}

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

  .page-about .about-legend__item,
  .page-about .about-version-tabs__tab,
  .page-about .about-version-tabs__tab::after {
    transition: none;
  }
}

.page-about {
  --w: 1rem;
}