.page-about {
  position: relative;
  --about-dot: rgba(57, 255, 20, 0.12);
  --about-copper-fade: rgba(184, 115, 51, 0.35);
}

.page-about .breadcrumbs {
  margin: 24px 0 8px;
}

.page-about__layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
  padding-bottom: 64px;
}

.page-about__content {
  min-width: 0;
}

/* 左侧章节索引 */
.page-about__index {
  background: var(--ink-panel);
  border: 1px solid var(--border-grid);
  border-left: 3px solid var(--neon-green);
  padding: 14px 16px;
  margin: 16px 0 8px;
}

.page-about__index-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 14px;
}

.page-about__index .section-code {
  display: none;
}

.page-about__index-title {
  font-family: var(--font-data);
  font-size: 13px;
  color: var(--copper);
  letter-spacing: 0.1em;
  margin: 0;
}

.page-about__index-list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 4px 8px;
  margin: 0;
  padding: 0;
}

.page-about__index-list li {
  margin: 0;
}

.page-about__index-list a {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 13px;
  padding: 4px 10px;
  border: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease), background 0.2s var(--ease);
}

.page-about__index-list a:hover {
  color: var(--neon-green);
  border-color: var(--border-grid);
  background: rgba(57, 255, 20, 0.05);
}

.page-about__index-list a span {
  font-family: var(--font-data);
  font-size: 11px;
  color: var(--copper);
}

.page-about__index-code {
  display: none;
}

/* 封面 */
.page-about__cover {
  padding: 32px 0 40px;
  border-bottom: 1px solid var(--border-grid);
  position: relative;
}

.page-about__cover::before {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 200px;
  height: 120px;
  background-image: radial-gradient(var(--border-grid) 1px, transparent 1px);
  background-size: 14px 14px;
  opacity: 0.5;
  pointer-events: none;
}

.page-about__cover::after {
  content: "2018 — NOW";
  position: absolute;
  right: 14px;
  bottom: 32px;
  font-family: var(--font-data);
  font-size: 12px;
  color: rgba(155, 177, 214, 0.4);
  letter-spacing: 0.12em;
  writing-mode: vertical-rl;
}

.page-about__cover-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 16px;
  margin-bottom: 20px;
}

.page-about__cover-status {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-data);
  font-size: 13px;
  color: var(--text-secondary);
}

.page-about__cover h1 {
  font-family: var(--font-headline);
  font-size: clamp(30px, 5vw, 54px);
  line-height: 1.06;
  letter-spacing: 0.01em;
  margin: 0 0 20px;
  color: var(--text-primary);
}

.page-about__cover-lead {
  font-size: 16px;
  line-height: 1.8;
  color: var(--text-secondary);
  max-width: 720px;
  margin: 0 0 28px;
}

.page-about__cover-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 28px;
}

.page-about__cover-stat {
  font-family: var(--font-data);
  font-size: 13px;
  color: var(--text-secondary);
}

.page-about__cover-stat strong {
  display: inline-block;
  margin-right: 4px;
  font-size: 24px;
  font-weight: 400;
  color: var(--neon-green);
}

/* 章节通用 */
.page-about__section {
  padding: 40px 0;
  border-bottom: 1px solid var(--border-grid);
  position: relative;
}

.page-about__section-head {
  margin-bottom: 16px;
}

.page-about__section-head .section-code {
  display: block;
  margin-bottom: 8px;
}

.page-about__section-head h2 {
  font-family: var(--font-headline);
  font-size: clamp(24px, 3.2vw, 38px);
  margin: 0;
  color: var(--text-primary);
}

.page-about__section-desc {
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-secondary);
  margin: 0 0 16px;
}

.page-about__section-desc a {
  color: var(--neon-green);
  text-decoration: underline;
  text-underline-offset: 4px;
}

/* 服务网格 */
.page-about__service-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin: 24px 0;
}

.page-about__service-item {
  background: var(--ink-panel);
  border: 1px solid var(--border-grid);
  padding: 18px 18px 18px 20px;
  position: relative;
  transition: border-color 0.3s var(--ease), transform 0.3s var(--ease);
}

.page-about__service-item::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 2px;
  height: 0;
  background: var(--neon-green);
  transition: height 0.3s var(--ease);
}

.page-about__service-item:hover {
  border-color: rgba(57, 255, 20, 0.4);
  transform: translateY(-2px);
}

.page-about__service-item:hover::before {
  height: 100%;
}

.page-about__service-index {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--copper);
}

.page-about__service-item h3 {
  font-family: var(--font-headline);
  font-size: 17px;
  margin: 0 0 6px;
  color: var(--text-primary);
}

.page-about__service-item p {
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-secondary);
  margin: 0;
}

/* 时间线 */
.page-about__timeline {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  position: relative;
}

.page-about__timeline::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(
    180deg,
    var(--neon-green),
    var(--border-grid) 35%,
    var(--border-grid) 70%,
    var(--copper)
  );
}

.page-about__timeline-item {
  position: relative;
  padding-left: 26px;
  margin-bottom: 24px;
}

.page-about__timeline-item:last-child {
  margin-bottom: 0;
}

.page-about__timeline-item::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 8px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--ink-deep);
  border: 2px solid var(--neon-green);
  box-shadow: 0 0 0 3px var(--about-dot);
}

.page-about__timeline-marker {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-data);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--neon-green);
}

.page-about__timeline-card {
  background: var(--ink-panel);
  border: 1px solid var(--border-grid);
  padding: 16px 18px;
  transition: border-color 0.3s var(--ease);
}

.page-about__timeline-item:hover .page-about__timeline-card,
.page-about__timeline-item:focus-within .page-about__timeline-card {
  border-color: rgba(57, 255, 20, 0.35);
}

.page-about__timeline-card h3 {
  font-family: var(--font-headline);
  font-size: 18px;
  margin: 8px 0 6px;
  color: var(--text-primary);
}

.page-about__timeline-card p {
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-secondary);
  margin: 0;
}

.page-about__timeline-more {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  margin: 0;
  padding-left: 12px;
  border-left: 2px solid var(--about-copper-fade);
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-secondary);
  transition: max-height 0.4s var(--ease), opacity 0.3s var(--ease), margin 0.3s var(--ease);
}

.page-about__timeline-item:hover .page-about__timeline-more,
.page-about__timeline-item:focus-within .page-about__timeline-more {
  max-height: 180px;
  opacity: 1;
  margin-top: 10px;
}

/* 数据卡片 */
.page-about__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin: 28px 0;
}

.page-about__fact {
  background: var(--ink-panel);
  border: 1px solid var(--border-grid);
  padding: 18px;
  position: relative;
}

.page-about__fact::before {
  content: attr(data-index);
  position: absolute;
  top: 10px;
  right: 10px;
  font-family: var(--font-data);
  font-size: 11px;
  color: var(--copper);
}

.page-about__fact-value {
  display: block;
  font-family: var(--font-data);
  font-size: clamp(26px, 3.5vw, 44px);
  line-height: 1;
  color: var(--neon-green);
}

.page-about__fact-label {
  display: block;
  margin-top: 10px;
  font-size: 13px;
  color: var(--text-primary);
}

.page-about__fact-detail {
  display: block;
  margin-top: 4px;
  font-size: 12px;
  line-height: 1.5;
  color: var(--text-secondary);
}

/* 数据表格 */
.page-about__data-table-wrap {
  margin: 24px 0;
  overflow-x: auto;
}

.page-about__data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  background: var(--ink-panel);
  border: 1px solid var(--border-grid);
}

.page-about__data-table th,
.page-about__data-table td {
  padding: 14px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border-grid);
}

.page-about__data-table thead th {
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--copper);
  background: rgba(184, 115, 51, 0.08);
}

.page-about__data-table tbody th {
  font-family: var(--font-headline);
  font-size: 15px;
  font-weight: 400;
  color: var(--text-primary);
  white-space: nowrap;
}

.page-about__data-table tbody td {
  color: var(--text-secondary);
}

.page-about__data-table tbody tr:last-child th,
.page-about__data-table tbody tr:last-child td {
  border-bottom: 0;
}

/* 图片 */
.page-about__figure {
  margin: 24px 0;
}

.page-about__figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--border-grid);
}

.page-about__figure--cert img {
  max-width: 320px;
}

/* 合规认证 */
.page-about__cert-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin: 24px 0;
}

.page-about__cert-item {
  background: var(--ink-panel);
  border: 1px solid var(--border-grid);
  padding: 18px;
  position: relative;
  transition: border-color 0.3s var(--ease);
}

.page-about__cert-item:hover {
  border-color: rgba(184, 115, 51, 0.55);
}

.page-about__cert-badge {
  display: inline-block;
  padding: 2px 8px;
  margin-bottom: 12px;
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--ink-deep);
  background: var(--highlight-gradient);
}

.page-about__cert-item h3 {
  font-family: var(--font-headline);
  font-size: 17px;
  margin: 0 0 6px;
  color: var(--text-primary);
}

.page-about__cert-item p {
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-secondary);
  margin: 0;
}

.page-about__compliance-media {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
  margin: 24px 0;
}

.page-about__compliance-note {
  margin-top: 28px;
  padding-top: 20px;
  border-top: 1px solid var(--border-grid);
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-secondary);
}

.page-about__compliance-note a {
  color: var(--neon-green);
}

/* 平板及以上 */
@media (min-width: 768px) {
  .page-about__layout {
    grid-template-columns: 200px minmax(0, 1fr);
    gap: 40px;
    align-items: start;
  }

  .page-about__index {
    margin: 16px 0 0;
    padding: 20px 18px;
    background: transparent;
    border: 0;
    border-left: 2px solid var(--border-grid);
  }

  .page-about__index-inner {
    position: sticky;
    top: 112px;
    display: block;
  }

  .page-about__index .section-code {
    display: block;
    margin-bottom: 24px;
  }

  .page-about__index-title {
    margin-bottom: 12px;
    font-size: 14px;
  }

  .page-about__index-list {
    display: block;
    margin-bottom: 24px;
  }

  .page-about__index-list li {
    border-bottom: 1px solid var(--border-grid);
  }

  .page-about__index-list a {
    display: flex;
    padding: 12px 0;
    font-size: 14px;
    border: 0;
    background: transparent;
  }

  .page-about__index-list a:hover {
    border-color: transparent;
    background: rgba(57, 255, 20, 0.05);
  }

  .page-about__index-code {
    display: block;
    padding-top: 16px;
    border-top: 1px solid var(--border-grid);
    font-family: var(--font-data);
    font-size: 11px;
    line-height: 1.8;
    color: var(--text-secondary);
  }

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

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

  .page-about__compliance-media {
    grid-template-columns: 1.6fr 1fr;
    align-items: center;
  }
}

/* 桌面 */
@media (min-width: 1024px) {
  .page-about__layout {
    grid-template-columns: 240px minmax(0, 1fr);
    gap: 56px;
  }

  .page-about__cover {
    padding: 48px 0 56px;
  }

  .page-about__section {
    padding: 52px 0;
  }

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

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

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition: none !important;
    animation: none !important;
    scroll-behavior: auto !important;
  }
}