.page-about {
  --about-index-gap: 20px;
  --about-line: #22304D;
  --about-glow-purple: rgba(123, 108, 246, 0.16);
  --about-glow-gold: rgba(232, 185, 106, 0.08);
}

.page-about .about-wrap {
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: 20px;
}

/* 面包屑 */
.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-block: 20px 0;
  font-family: var(--font-number);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--color-text-secondary);
}

.page-about .breadcrumb a {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--speed) ease;
}

.page-about .breadcrumb a:hover {
  color: var(--color-gold);
}

.page-about .breadcrumb__sep {
  color: var(--color-grid);
}

.page-about .breadcrumb [aria-current="page"] {
  color: var(--color-gold);
}

/* 首屏氛围 */
.page-about .archive-hero {
  position: relative;
  padding-block: 56px 0;
  background:
    radial-gradient(900px 520px at 88% 10%, var(--about-glow-purple), transparent 65%),
    radial-gradient(720px 420px at 8% 88%, var(--about-glow-gold), transparent 55%);
}

.page-about .archive-hero__grid {
  display: grid;
  gap: 36px;
  padding-block: 8px;
}

.page-about .archive-hero__content {
  position: relative;
  z-index: 1;
}

.page-about .section-index {
  margin: 0;
  font-family: var(--font-number);
  font-size: 0.78rem;
  letter-spacing: 0.2em;
  color: var(--color-purple);
  text-transform: uppercase;
}

.page-about h1 {
  max-width: 10em;
  margin-block: 18px 20px;
  font-family: var(--font-heading);
  font-weight: 300;
  font-size: clamp(1.9rem, 2.8vw + 1rem, 3.1rem);
  line-height: 1.3;
  letter-spacing: 0.06em;
  color: var(--color-text-primary);
}

.page-about .archive-hero__lead {
  max-width: 33em;
  margin: 0;
  font-family: var(--font-body);
  font-size: 0.95rem;
  line-height: 1.75;
  color: var(--color-text-secondary);
}

.page-about .archive-specs {
  display: flex;
  flex-wrap: wrap;
  gap: 18px 32px;
  margin: 32px 0 0;
  padding: 20px 0 0;
  border-top: 1px solid var(--about-line);
  text-align: left;
}

.page-about .archive-specs dt {
  font-family: var(--font-number);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--color-text-secondary);
  text-transform: uppercase;
}

.page-about .archive-specs dd {
  margin: 4px 0 0;
  font-size: 0.9rem;
  color: var(--color-text-primary);
}

.page-about .archive-hero__figure {
  position: relative;
  margin: 0;
}

.page-about .archive-hero__figure::after {
  content: "";
  position: absolute;
  inset: 12px 12px -12px 12px;
  border: 1px solid rgba(123, 108, 246, 0.28);
  border-radius: var(--radius-lg);
  pointer-events: none;
}

.page-about .archive-hero__figure img {
  position: relative;
  z-index: 1;
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--color-grid);
  border-radius: var(--radius-lg);
  object-fit: cover;
}

/* 章节索引条 */
.page-about .about-index {
  margin-top: 48px;
  border-block: 1px solid var(--about-line);
  background: rgba(10, 30, 60, 0.24);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
}

.page-about .about-index__list a {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding-block: 14px;
  font-size: 0.9rem;
  color: var(--color-text-primary);
  text-decoration: none;
  border-bottom: 1px solid rgba(34, 48, 77, 0.6);
  transition: color var(--speed) ease;
}

.page-about .about-index__list li:last-child a {
  border-bottom: 0;
}

.page-about .about-index__list a span {
  font-family: var(--font-number);
  font-size: 0.72rem;
  color: var(--color-purple);
}

.page-about .about-index__list a:hover {
  color: var(--color-gold);
}

/* 站点定位 */
.page-about .position-section {
  padding-block: 72px 32px;
  background: linear-gradient(180deg, rgba(10, 30, 60, 0.42) 0%, rgba(10, 30, 60, 0) 100%);
}

.page-about .position-layout {
  display: grid;
  gap: 36px;
}

.page-about .editorial-quote {
  margin: 0;
  font-family: var(--font-editorial);
  font-size: 1.06rem;
  line-height: 1.85;
  color: var(--color-text-primary);
  border-left: 2px solid var(--color-gold);
  padding-left: 18px;
}

.page-about .position-scope {
  display: grid;
  gap: 24px;
}

.page-about .scope-col h3 {
  margin: 0 0 12px;
  font-family: var(--font-heading);
  font-weight: 300;
  font-size: 1rem;
  letter-spacing: 0.06em;
  color: var(--color-gold);
}

.page-about .scope-col ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .scope-col li {
  position: relative;
  padding-left: 18px;
  font-size: 0.9rem;
  line-height: 1.65;
  color: var(--color-text-secondary);
}

.page-about .scope-col li::before {
  content: "—";
  position: absolute;
  left: 0;
  font-family: var(--font-number);
  color: var(--color-purple);
}

.page-about .scope-col:last-child li::before {
  content: "×";
  color: var(--color-warning);
}

/* 版本档案 */
.page-about .version-archive {
  padding-block: 72px 88px;
  background:
    linear-gradient(180deg, rgba(30, 27, 75, 0.28) 0%, rgba(10, 30, 60, 0.28) 100%),
    var(--color-bg);
}

.page-about .section-heading {
  margin-bottom: 28px;
}

.page-about .section-star {
  display: inline-block;
  margin-right: 8px;
  vertical-align: -2px;
  color: var(--color-gold);
}

.page-about .section-intro {
  max-width: 48em;
  margin: 0 0 36px;
  font-size: 0.95rem;
  line-height: 1.75;
  color: var(--color-text-secondary);
}

.page-about .section-intro a {
  color: var(--color-gold);
  text-decoration: none;
  border-bottom: 1px solid rgba(232, 185, 106, 0.4);
  transition: border-color var(--speed) ease;
}

.page-about .section-intro a:hover {
  border-color: var(--color-gold);
}

.page-about .version-layout {
  display: grid;
  gap: 40px;
}

/* 时间轴 */
.page-about .timeline {
  position: relative;
  margin: 0;
  padding: 4px 0 0;
  list-style: none;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 14px;
  width: 1px;
  background: linear-gradient(180deg, var(--color-grid), var(--color-gold) 45%, var(--color-grid));
}

.page-about .timeline-item {
  position: relative;
  padding: 0 0 40px 44px;
}

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

.page-about .timeline-item::before {
  content: "";
  position: absolute;
  top: 24px;
  left: 9px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--color-bg);
  border: 2px solid var(--color-gold);
  box-shadow: 0 0 0 3px rgba(232, 185, 106, 0.15);
}

.page-about .timeline-item:last-child::before {
  background: var(--color-gold);
}

.page-about .timeline-item__head {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}

.page-about .timeline-tag {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 42px;
  padding: 4px 10px;
  font-family: var(--font-number);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--color-purple);
  border: 1px solid var(--color-grid);
  border-radius: 999px;
}

.page-about .timeline-item__head h3 {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: 300;
  font-size: 1.15rem;
  letter-spacing: 0.05em;
  color: var(--color-text-primary);
}

.page-about .timeline-item__body {
  padding: 20px;
  background: linear-gradient(145deg, rgba(255, 255, 255, 0.07), rgba(255, 255, 255, 0.02));
  border: 1px solid var(--color-grid);
  border-radius: var(--radius-md);
}

.page-about .timeline-desc {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.7;
  color: var(--color-text-secondary);
}

.page-about .timeline-details {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px dashed var(--color-grid);
}

.page-about .timeline-details summary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  transition: color var(--speed) ease;
}

.page-about .timeline-details summary:hover {
  color: var(--color-gold);
}

.page-about .timeline-details summary::before {
  content: "+";
  font-family: var(--font-number);
  color: var(--color-gold);
}

.page-about .timeline-details[open] summary::before {
  content: "–";
}

.page-about .timeline-details ul {
  list-style: none;
  margin: 12px 0 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.page-about .timeline-details li {
  position: relative;
  padding-left: 16px;
  font-size: 0.85rem;
  line-height: 1.6;
  color: var(--color-text-secondary);
}

.page-about .timeline-details li::before {
  content: "·";
  position: absolute;
  left: 0;
  color: var(--color-gold);
}

.page-about .timeline-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin-top: 14px;
}

.page-about .timeline-links a {
  font-size: 0.85rem;
  color: var(--color-gold);
  text-decoration: none;
  border-bottom: 1px solid rgba(232, 185, 106, 0.4);
  transition: border-color var(--speed) ease;
}

.page-about .timeline-links a:hover {
  border-color: var(--color-gold);
}

.page-about .version-figure {
  margin: 0;
}

.page-about .version-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--color-grid);
  border-radius: var(--radius-lg);
  object-fit: cover;
}

/* 内容收录与更新 */
.page-about .coverage-section {
  padding-block: 72px 80px;
  background-image:
    linear-gradient(rgba(34, 48, 77, 0.16) 1px, transparent 1px),
    linear-gradient(90deg, rgba(34, 48, 77, 0.16) 1px, transparent 1px);
  background-size: 28px 28px;
}

.page-about .coverage-grid {
  display: grid;
  gap: 28px;
}

.page-about .coverage-intro p {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.75;
  color: var(--color-text-secondary);
}

.page-about .metrics-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.page-about .metric {
  padding: 18px 16px;
  background: var(--color-glass);
  border: 1px solid var(--color-grid);
  border-radius: var(--radius-md);
}

.page-about .metric__num {
  display: block;
  font-family: var(--font-number);
  font-size: 1.7rem;
  font-weight: 500;
  line-height: 1.2;
  color: var(--color-gold);
}

.page-about .metric__label {
  display: block;
  margin-top: 6px;
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  color: var(--color-text-secondary);
}

.page-about .coverage-schedule h3,
.page-about .coverage-rules h3 {
  margin: 0 0 14px;
  font-family: var(--font-heading);
  font-weight: 300;
  font-size: 1rem;
  letter-spacing: 0.06em;
  color: var(--color-gold);
}

.page-about .update-list,
.page-about .data-rules {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  border-top: 1px solid var(--color-grid);
}

.page-about .update-list li,
.page-about .data-rules li {
  padding: 14px 0;
  border-bottom: 1px solid rgba(34, 48, 77, 0.55);
  font-size: 0.88rem;
  line-height: 1.65;
  color: var(--color-text-secondary);
}

.page-about .update-list li:last-child,
.page-about .data-rules li:last-child {
  border-bottom: 0;
}

.page-about .update-list__phase {
  display: block;
  margin-bottom: 4px;
  font-family: var(--font-number);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-purple);
}

.page-about .update-list li p {
  margin: 0;
}

.page-about .data-rules li {
  position: relative;
  padding-left: 18px;
}

.page-about .data-rules li::before {
  content: "◆";
  position: absolute;
  top: 16px;
  left: 0;
  font-size: 0.55rem;
  color: var(--color-gold);
}

.page-about .coverage-figure {
  margin: 0;
}

.page-about .coverage-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--color-grid);
  border-radius: var(--radius-lg);
  object-fit: cover;
}

/* 隐私与合规 */
.page-about .compliance-section {
  padding-block: 64px 96px;
  background: linear-gradient(180deg, transparent, rgba(10, 30, 60, 0.5));
}

.page-about .compliance-panel {
  display: grid;
  gap: 28px;
  padding: 32px 24px;
  background: var(--color-glass);
  border: 1px solid var(--color-grid);
  border-radius: var(--radius-lg);
}

.page-about .compliance-copy p {
  margin: 0 0 12px;
  font-size: 0.9rem;
  line-height: 1.75;
  color: var(--color-text-secondary);
}

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

.page-about .compliance-note {
  font-family: var(--font-body);
}

.page-about .compliance-icp {
  font-family: var(--font-number);
  font-size: 0.8rem;
  color: var(--color-text-secondary);
}

.page-about .compliance-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
}

/* 响应式 */
@media (min-width: 480px) {
  .page-about .position-scope {
    grid-template-columns: 1fr 1fr;
  }
}

@media (min-width: 768px) {
  .page-about .about-wrap {
    padding-inline: 32px;
  }

  .page-about .archive-hero__grid {
    grid-template-columns: 7fr 5fr;
    align-items: center;
    gap: 48px;
  }

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

  .page-about .about-index__list a {
    justify-content: center;
    border-right: 1px solid rgba(34, 48, 77, 0.6);
    border-bottom: 0;
  }

  .page-about .about-index__list li:last-child a {
    border-right: 0;
  }

  .page-about .position-layout {
    grid-template-columns: 4fr 6fr;
    gap: 56px;
  }

  .page-about .timeline::before {
    left: 50%;
  }

  .page-about .timeline-item {
    width: calc(50% - 34px);
    padding: 0;
  }

  .page-about .timeline-item:nth-child(odd) {
    margin-right: auto;
  }

  .page-about .timeline-item:nth-child(even) {
    margin-left: auto;
  }

  .page-about .timeline-item::before {
    top: 26px;
    left: auto;
  }

  .page-about .timeline-item:nth-child(odd)::before {
    right: -39px;
  }

  .page-about .timeline-item:nth-child(even)::before {
    left: -39px;
  }

  .page-about .compliance-panel {
    grid-template-columns: 1fr auto;
    align-items: center;
    gap: 40px;
    padding: 40px;
  }
}

@media (min-width: 992px) {
  .page-about .version-layout {
    grid-template-columns: minmax(0, 1fr) 340px;
    align-items: start;
    gap: 56px;
  }

  .page-about .coverage-grid {
    grid-template-columns: 5fr 4fr;
    column-gap: 56px;
  }

  .page-about .coverage-intro {
    grid-column: 1 / -1;
    max-width: 46em;
  }

  .page-about .coverage-metrics {
    grid-column: 1;
    grid-row: 2;
  }

  .page-about .coverage-schedule {
    grid-column: 2;
    grid-row: 2;
  }

  .page-about .coverage-figure {
    grid-column: 1;
    grid-row: 3;
  }

  .page-about .coverage-rules {
    grid-column: 2;
    grid-row: 3;
  }
}