.page-about {
  --about-index-w: 176px;
  --about-ver-gut: clamp(14px, 2vw, 26px);
  display: block;
  background: var(--paper-000);
  color: var(--ink-900);
}

.page-about .about-shell {
  width: 100%;
  max-width: var(--content-max);
  margin-inline: auto;
  padding-inline: clamp(16px, 4vw, 40px);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding-top: clamp(20px, 3.5vw, 40px);
  padding-bottom: clamp(22px, 3vw, 38px);
}

.page-about .about-hero .breadcrumb {
  margin-bottom: clamp(18px, 3vw, 30px);
}

.page-about .about-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3.4vw, 44px);
  align-items: start;
}

@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.32fr) minmax(0, 0.85fr);
    align-items: end;
  }
}

.page-about .about-kicker {
  margin: 0 0 12px;
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  color: var(--mint-600);
}

.page-about .about-h1 {
  margin: 0 0 0.55em;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.85rem, 4.6vw, 3.3rem);
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--ink-900);
}

.page-about .about-lede {
  margin: 0;
  max-width: 48ch;
  font-size: clamp(0.95rem, 1.6vw, 1.0625rem);
  line-height: 1.85;
  color: var(--ink-700);
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--line-200);
  border: 1px solid var(--line-200);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-stat {
  background: var(--paper-100);
  padding: clamp(12px, 1.8vw, 18px);
}

.page-about .about-stat-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.15rem, 3.4vw, 1.5rem);
  font-weight: 700;
  line-height: 1.2;
  color: var(--ink-900);
  margin-bottom: 6px;
}

.page-about .about-stat-label {
  display: block;
  font-size: 0.75rem;
  line-height: 1.5;
  letter-spacing: 0.04em;
  color: var(--slate-500);
}

/* ---------- 通栏窄带 ---------- */

.page-about .about-band {
  margin: 0;
  background: var(--paper-000);
}

.page-about .about-band-media {
  display: block;
  width: 100%;
  height: clamp(140px, 22vw, 260px);
  object-fit: cover;
  background: var(--night-800);
}

.page-about .about-band-caption {
  max-width: var(--content-max);
  margin-inline: auto;
  padding: 12px clamp(16px, 4vw, 40px) 0;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--slate-500);
}

/* ---------- 主画布 ---------- */

.page-about .about-main {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 3.5vw, 48px);
  padding-top: clamp(28px, 4vw, 52px);
  padding-bottom: clamp(48px, 7vw, 88px);
}

@media (min-width: 1024px) {
  .page-about .about-main {
    grid-template-columns: var(--about-index-w) minmax(0, 1fr);
    align-items: start;
  }
}

.page-about .about-column {
  min-width: 0;
}

/* ---------- 侧栏索引 ---------- */

.page-about .about-index {
  display: none;
}

@media (min-width: 1024px) {
  .page-about .about-index {
    display: block;
    position: sticky;
    top: calc(var(--bar-h) + 32px);
  }
}

.page-about .about-index-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 2px;
  border-left: 1px solid var(--line-200);
}

.page-about .about-index-link {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: baseline;
  gap: 10px;
  padding: 9px 12px;
  border-left: 2px solid transparent;
  margin-left: -1px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--slate-500);
  font-size: 0.875rem;
  line-height: 1.4;
  text-decoration: none;
  transition: color 180ms var(--ease), background-color 180ms var(--ease), border-color 180ms var(--ease);
}

.page-about .about-index-link:hover,
.page-about .about-index-link:focus-visible {
  color: var(--ink-900);
  background: var(--mint-050);
  border-left-color: var(--mint-500);
}

.page-about .about-index-link:focus-visible {
  outline: 2px solid var(--mint-500);
  outline-offset: 2px;
}

.page-about .about-index-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 0.6875rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--mint-600);
}

/* ---------- 章节通用 ---------- */

.page-about .about-section {
  padding-block: clamp(28px, 4vw, 46px);
  border-top: 1px solid var(--line-200);
}

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

.page-about .about-h2 {
  margin: 0 0 0.7em;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.45rem, 3.1vw, 2.15rem);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--ink-900);
}

.page-about .about-p {
  margin: 0 0 1em;
  max-width: 66ch;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--ink-700);
}

.page-about .about-p:last-child {
  margin-bottom: 0;
}

.page-about .about-p a {
  color: var(--ink-900);
  text-decoration: underline;
  text-decoration-color: var(--mint-500);
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

.page-about .about-p a:hover,
.page-about .about-p a:focus-visible {
  color: var(--mint-600);
}

/* ---------- 版本时间线 ---------- */

.page-about .about-versions {
  margin: 8px 0 0 6px;
  padding-left: var(--about-ver-gut);
  border-left: 2px solid var(--line-200);
}

.page-about .ver {
  position: relative;
  padding: 16px 0;
  border-top: 1px solid var(--line-200);
}

.page-about .ver:first-child {
  border-top: 0;
  padding-top: 10px;
}

.page-about .ver::before {
  content: "";
  position: absolute;
  top: 22px;
  left: calc(-1 * var(--about-ver-gut) - 6px);
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--paper-000);
  border: 2px solid var(--mint-500);
  transition: background-color 200ms var(--ease);
}

.page-about .ver:first-child::before {
  top: 16px;
}

.page-about .ver[open]::before {
  background: var(--mint-500);
}

.page-about .ver-head {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 14px;
  padding-right: 30px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .ver-head::marker {
  content: "";
}

.page-about .ver-head:focus-visible {
  outline: 2px solid var(--mint-500);
  outline-offset: 4px;
  border-radius: var(--radius-sm);
}

.page-about .ver-head::after {
  content: "";
  position: absolute;
  right: 4px;
  top: 5px;
  width: 12px;
  height: 12px;
  background-image:
    linear-gradient(var(--mint-600), var(--mint-600)),
    linear-gradient(var(--mint-600), var(--mint-600));
  background-position: center center, center center;
  background-size: 12px 2px, 2px 12px;
  background-repeat: no-repeat;
  transition: background-size 220ms var(--ease);
}

.page-about .ver[open] .ver-head::after {
  background-size: 12px 2px, 2px 0;
}

.page-about .ver-id {
  flex: 0 0 auto;
  padding: 2px 8px;
  border: 1px solid var(--ink-900);
  border-radius: var(--radius-sm);
  background: var(--paper-100);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--ink-900);
}

.page-about .ver-years {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 0.75rem;
  letter-spacing: 0.02em;
  color: var(--slate-500);
}

.page-about .ver-title {
  flex: 1 1 auto;
  min-width: 55%;
  font-family: var(--font-sans);
  font-size: 1.0625rem;
  font-weight: 700;
  line-height: 1.45;
  color: var(--ink-900);
}

.page-about .ver-body {
  padding: 10px 0 2px;
  max-width: 60ch;
}

.page-about .ver-body p {
  margin: 0 0 8px;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--ink-700);
}

.page-about .ver-body p:last-child {
  margin-bottom: 0;
}

.page-about .ver-tag {
  display: inline-block;
  margin-right: 8px;
  padding: 1px 7px;
  border-radius: 3px;
  background: var(--mint-050);
  color: var(--mint-600);
  font-size: 0.6875rem;
  font-weight: 700;
  letter-spacing: 0.06em;
}

/* ---------- 图形 ---------- */

.page-about .about-figure {
  margin: clamp(24px, 3.5vw, 38px) 0 0;
  max-width: 620px;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line-200);
  border-radius: var(--radius);
  background: var(--paper-100);
}

.page-about .about-figure figcaption {
  margin-top: 10px;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--slate-500);
}

/* ---------- 三条做法 ---------- */

.page-about .about-principles {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: 12px;
  background: var(--line-200);
  border: 1px solid var(--line-200);
  border-radius: var(--radius);
  overflow: hidden;
}

@media (min-width: 760px) {
  .page-about .about-principles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .principle {
  background: var(--paper-100);
  padding: clamp(18px, 2.4vw, 26px);
}

.page-about .principle-idx {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--coral-500);
}

.page-about .principle-h {
  margin: 0 0 10px;
  font-family: var(--font-sans);
  font-size: 1.0625rem;
  font-weight: 700;
  line-height: 1.5;
  color: var(--ink-900);
}

.page-about .principle p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--ink-700);
}

/* ---------- 历年节点 ---------- */

.page-about .about-miles {
  margin: 10px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .mile {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 16px 0;
  border-top: 1px solid var(--line-200);
}

.page-about .mile:first-child {
  border-top: 0;
  padding-top: 4px;
}

@media (min-width: 700px) {
  .page-about .mile {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 22px;
    align-items: baseline;
  }
}

.page-about .mile-year {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--ink-900);
}

.page-about .mile-h {
  margin: 0 0 5px;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.5;
  color: var(--ink-900);
}

.page-about .mile-body p {
  margin: 0;
  max-width: 62ch;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--ink-700);
}

/* ---------- 底部行动区 ---------- */

.page-about .about-cta {
  background: var(--ink-900);
  color: var(--paper-000);
}

.page-about .about-cta-inner {
  padding-top: clamp(38px, 6vw, 72px);
  padding-bottom: clamp(38px, 6vw, 72px);
}

.page-about .about-cta-h {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.5rem, 3.4vw, 2.2rem);
  line-height: 1.2;
  color: var(--paper-000);
}

.page-about .about-cta-p {
  margin: 0 0 26px;
  max-width: 58ch;
  font-size: 0.9375rem;
  line-height: 1.85;
  color: rgba(251, 249, 244, 0.74);
}

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

.page-about .about-cta-actions .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 20px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 600;
  text-decoration: none;
  transition: background-color 180ms var(--ease), border-color 180ms var(--ease), color 180ms var(--ease);
}

.page-about .about-cta-actions .btn-mint {
  background: var(--mint-500);
  border-color: var(--mint-500);
  color: var(--ink-900);
}

.page-about .about-cta-actions .btn-mint:hover,
.page-about .about-cta-actions .btn-mint:focus-visible {
  background: var(--mint-600);
  border-color: var(--mint-600);
}

.page-about .about-cta-actions .btn-ghost {
  background: transparent;
  border-color: rgba(251, 249, 244, 0.38);
  color: var(--paper-000);
}

.page-about .about-cta-actions .btn-ghost:hover,
.page-about .about-cta-actions .btn-ghost:focus-visible {
  border-color: var(--mint-500);
  color: var(--mint-500);
}

.page-about .about-cta-actions .btn:focus-visible {
  outline: 2px solid var(--mint-500);
  outline-offset: 3px;
}

/* ---------- 动效降级 ---------- */

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index-link,
  .page-about .ver::before,
  .page-about .ver-head::after,
  .page-about .about-cta-actions .btn {
    transition: none;
  }
}