.page-about {
  --about-rail: 168px;
  display: block;
  background: var(--ink);
  color: var(--paper);
}

.page-about .about-topline {
  padding-top: 26px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 36px 0 52px;
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: -140px -10% auto -10%;
  height: 340px;
  background:
    radial-gradient(60% 100% at 18% 40%, rgba(92, 140, 255, 0.16), transparent 70%),
    radial-gradient(45% 90% at 78% 10%, rgba(232, 65, 44, 0.14), transparent 72%);
  pointer-events: none;
  z-index: 0;
}

.page-about .about-hero-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 34px;
}

.page-about .about-hero-main .lede {
  max-width: 46ch;
  margin-top: 18px;
}

.page-about .about-hero-side {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about .hero-metric {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 16px;
  background: var(--panel);
}

.page-about .hero-num {
  font-family: var(--font-data);
  font-variant-numeric: tabular-nums;
  font-size: 40px;
  font-weight: 700;
  line-height: 1.05;
  color: var(--hi);
  letter-spacing: -0.02em;
}

.page-about .hero-label {
  font-size: 13px;
  font-weight: 300;
  color: var(--muted);
}

/* ---------- 通用分段 ---------- */
.page-about .about-band {
  padding: 48px 0;
  border-top: 1px solid var(--line);
}

.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
}

.page-about .about-rail .eyebrow {
  margin-bottom: 12px;
}

.page-about .rail-note {
  margin: 0;
  font-family: var(--font-data);
  font-size: 13px;
  font-weight: 300;
  line-height: 1.9;
  color: var(--muted);
  border-left: 2px solid var(--line);
  padding-left: 12px;
}

.page-about .about-body > .section-title {
  margin-bottom: 18px;
}

.page-about .about-body p {
  margin: 0 0 16px;
}

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

.page-about .about-body a,
.page-about .metric-detail-body a {
  color: var(--link);
  text-decoration: none;
  border-bottom: 1px solid rgba(92, 140, 255, 0.4);
}

.page-about .about-body a:hover,
.page-about .metric-detail-body a:hover {
  border-bottom-color: var(--link);
}

/* ---------- 筛选条 ---------- */
.page-about .filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 26px 0 30px;
}

.page-about .filter-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  border-radius: var(--r-pill);
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--muted);
  font-family: var(--font-head);
  font-size: 14px;
  font-weight: 400;
  cursor: pointer;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .filter-btn:hover {
  color: var(--paper);
  border-color: rgba(56, 242, 153, 0.4);
}

.page-about .filter-btn:focus-visible {
  outline: 2px solid var(--link);
  outline-offset: 2px;
}

.page-about .filter-btn[aria-pressed="true"] {
  color: var(--hi);
  border-color: var(--green);
  background: rgba(56, 242, 153, 0.08);
}

.page-about .filter-count {
  font-family: var(--font-data);
  font-variant-numeric: tabular-nums;
  font-size: 12px;
  color: var(--green);
}

/* ---------- 指标卡 ---------- */
.page-about .metric-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
}

.page-about .metric-card {
  position: relative;
  padding: 24px 22px 22px 30px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about .metric-card::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 4px;
  background: var(--metric-accent, var(--line));
}

.page-about .metric-card--cards { --metric-accent: var(--red); }
.page-about .metric-card--goal { --metric-accent: var(--yellow); }
.page-about .metric-card--stoppage { --metric-accent: var(--green); }

.page-about .metric-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

.page-about .metric-title {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--hi);
}

.page-about .metric-lead {
  margin: 0 0 20px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--paper);
}

.page-about .metric-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0 0 18px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--r-sm);
  overflow: hidden;
}

.page-about .metric-cell {
  padding: 14px 14px 16px;
  background: var(--ink);
}

.page-about .metric-cell dt {
  font-size: 13px;
  font-weight: 300;
  color: var(--muted);
  margin-bottom: 8px;
}

.page-about .metric-cell dd {
  margin: 0;
}

.page-about .metric-num {
  font-family: var(--font-data);
  font-variant-numeric: tabular-nums;
  font-size: 34px;
  font-weight: 700;
  line-height: 1.05;
  color: var(--hi);
  letter-spacing: -0.02em;
}

.page-about .metric-num small {
  font-size: 13px;
  font-weight: 400;
  color: var(--muted);
  margin: 0 1px;
}

.page-about .metric-num--sm {
  font-size: 20px;
  letter-spacing: 0;
  color: var(--paper);
}

.page-about .metric-detail {
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

.page-about .metric-detail summary {
  cursor: pointer;
  font-size: 14px;
  color: var(--link);
  list-style: none;
}

.page-about .metric-detail summary::-webkit-details-marker {
  display: none;
}

.page-about .metric-detail summary::after {
  content: " +";
  font-family: var(--font-data);
  color: var(--muted);
}

.page-about .metric-detail[open] summary::after {
  content: " −";
}

.page-about .metric-detail summary:focus-visible {
  outline: 2px solid var(--link);
  outline-offset: 3px;
}

.page-about .metric-detail-body {
  padding-top: 12px;
}

.page-about .metric-detail-body p {
  margin: 0 0 10px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--paper);
}

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

/* ---------- 图片容器微调 ---------- */
.page-about .media-frame {
  margin: 0;
}

.page-about .media-frame--about-goal {
  border-radius: var(--r-md);
  border: 1px solid var(--line);
  overflow: hidden;
  background: var(--panel);
}

.page-about .media-frame--about-goal img,
.page-about .media-frame--about-process img,
.page-about .media-frame--wide img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .media-frame figcaption {
  padding: 10px 14px;
}

/* ---------- 流程 ---------- */
.page-about .about-process-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
}

.page-about .about-process-main > .section-title {
  margin-bottom: 26px;
}

.page-about .process-list {
  position: relative;
  list-style: none;
  margin: 0 0 20px;
  padding: 0;
}

.page-about .process-list::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 14px;
  bottom: 26px;
  width: 1px;
  background: var(--line);
}

.page-about .process-item {
  position: relative;
  padding: 0 0 28px 30px;
}

.page-about .process-item:last-child {
  padding-bottom: 6px;
}

.page-about .process-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 13px;
  height: 13px;
  box-sizing: border-box;
  border-radius: var(--r-pill);
  background: var(--ink);
  border: 2px solid var(--node, var(--line));
}

.page-about .process-item--red { --node: var(--red); }
.page-about .process-item--yellow { --node: var(--yellow); }
.page-about .process-item--green { --node: var(--green); }

.page-about .process-title {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 700;
  color: var(--hi);
  letter-spacing: -0.01em;
}

.page-about .process-item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--paper);
}

.page-about .media-frame--about-process {
  border-radius: var(--r-md);
  border: 1px solid var(--line);
  overflow: hidden;
  background: var(--panel);
}

/* ---------- 演进 ---------- */
.page-about .about-history-figure {
  border-radius: var(--r-md);
  border: 1px solid var(--line);
  overflow: hidden;
  background: var(--panel);
  margin: 0 0 34px;
}

.page-about .version-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
}

.page-about .version-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 20px 0;
  border-top: 1px solid var(--line);
}

.page-about .version-row:first-child {
  border-top: 1px solid var(--line);
}

.page-about .version-tag {
  font-family: var(--font-data);
  font-variant-numeric: tabular-nums;
  font-size: 24px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--muted);
  letter-spacing: -0.02em;
}

.page-about .version-row--current .version-tag {
  color: var(--green);
}

.page-about .version-title {
  margin: 0 0 8px;
  font-size: 19px;
  font-weight: 700;
  line-height: 1.35;
  color: var(--hi);
  letter-spacing: -0.01em;
}

.page-about .version-body p {
  margin: 0 0 8px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--paper);
}

.page-about .version-gain {
  font-family: var(--font-data);
  font-size: 13px;
  font-weight: 300;
  color: var(--muted);
  transition: color var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.page-about .version-foot {
  margin-top: 26px;
  max-width: 60ch;
}

/* ---------- 团队 ---------- */
.page-about .team-list {
  list-style: none;
  margin: 0 0 20px;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .team-item {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  grid-template-areas:
    "count role"
    "count desc";
  gap: 2px 16px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .team-count {
  grid-area: count;
  font-family: var(--font-data);
  font-variant-numeric: tabular-nums;
  font-size: 30px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--hi);
  text-align: right;
}

.page-about .team-role {
  grid-area: role;
  font-size: 16px;
  font-weight: 700;
  color: var(--paper);
}

.page-about .team-desc {
  grid-area: desc;
  font-size: 14px;
  font-weight: 300;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------- 收尾 ---------- */
.page-about .about-coda {
  padding: 96px 0 120px;
  border-top: 1px solid var(--line);
}

.page-about .about-coda-inner {
  max-width: 40ch;
}

.page-about .coda-line {
  margin: 0 0 14px;
  font-size: 28px;
  font-weight: 700;
  line-height: 1.4;
  letter-spacing: -0.02em;
  color: var(--hi);
}

.page-about .about-coda .note {
  margin: 0;
}

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-about .metric-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .about-hero-side {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 56px 0 72px;
  }

  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: 72px;
    align-items: end;
  }

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

  .page-about .hero-num {
    font-size: 44px;
  }

  .page-about .about-band {
    padding: 72px 0;
  }

  .page-about .about-split {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 48px;
  }

  .page-about .metric-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    align-items: start;
  }

  .page-about .media-frame--about-goal {
    grid-column: 1 / -1;
    max-width: 640px;
  }

  .page-about .about-process-grid {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .version-row {
    grid-template-columns: 108px minmax(0, 1fr);
    gap: 28px;
    padding: 24px 0;
  }

  .page-about .version-tag {
    text-align: right;
    font-size: 28px;
    padding-top: 2px;
  }

  .page-about .version-gain {
    opacity: 0.5;
  }

  .page-about .version-row:hover .version-gain,
  .page-about .version-row:focus-within .version-gain {
    opacity: 1;
    color: var(--green);
  }

  .page-about .about-coda {
    padding: 140px 0 180px;
  }

  .page-about .coda-line {
    font-size: 40px;
  }
}

@media (min-width: 1080px) {
  .page-about .metric-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .media-frame--about-goal {
    grid-column: span 1;
    max-width: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .version-gain,
  .page-about .filter-btn {
    transition: none;
  }
}