.page-about {
  --about-font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --about-font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --about-deep-blue: #003366;
  --about-electric-purple: #7B2D8E;
  --about-vibrant-orange: #FF6F00;
  --about-tech-white: #F5F5F5;
  --about-deep-space-gray: #1A1A2E;
  --about-data-green: #00C853;
  --about-alert-red: #D32F2F;
  --about-soft-purple: #E1BEE7;
  --about-transition: 0.3s ease-in-out;
  --about-max-width: 1200px;
  --about-font-data: 'JetBrains Mono', 'Courier New', monospace;
}

/* 整体网格 移动端单列 */
.page-about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  padding: 1.5rem 1rem;
  max-width: var(--about-max-width);
  margin: 0 auto;
  position: relative;
}

/* 左侧时间轴 */
.about-timeline {
  background-color: var(--about-deep-blue);
  border: 1px solid var(--about-electric-purple);
  padding: 1.5rem;
  position: relative;
  border-radius: 0.5rem;
  box-shadow: 0 4px 12px rgba(0, 51, 102, 0.3);
}

.timeline-cover-img img {
  width: 100%;
  height: auto;
  max-width: 100%;
  display: block;
  border: 2px solid var(--about-electric-purple);
  border-radius: 0.25rem;
}

.timeline-year-bar {
  display: flex;
  gap: 0.75rem;
  margin: 1rem 0 1.5rem;
  justify-content: center;
}

.timeline-tag {
  background-color: var(--about-deep-space-gray);
  color: var(--about-tech-white);
  padding: 0.25rem 0.75rem;
  border-radius: 1rem;
  font-family: var(--about-font-data);
  font-size: 0.875rem;
  border: 1px solid var(--about-electric-purple);
}

.timeline-tag.active {
  background-color: var(--about-electric-purple);
  color: #fff;
  border-color: var(--about-vibrant-orange);
}

.timeline-track {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.timeline-node {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 0.75rem;
  background-color: rgba(245, 245, 245, 0.05);
  border-left: 3px solid var(--about-electric-purple);
  border-radius: 0.25rem;
  transition: background-color var(--about-transition), border-color var(--about-transition);
}

.timeline-node:hover,
.timeline-node:focus-within {
  background-color: rgba(123, 45, 142, 0.15);
  border-left-color: var(--about-vibrant-orange);
}

.node-badge {
  background-color: var(--about-vibrant-orange);
  color: #fff;
  font-family: var(--about-font-data);
  font-weight: 700;
  padding: 0.25rem 0.6rem;
  border-radius: 0.25rem;
  font-size: 0.875rem;
  line-height: 1;
  flex-shrink: 0;
}

.node-content {
  flex: 1;
}

.node-heading {
  font-family: var(--about-font-heading);
  font-weight: 700;
  font-size: 1.125rem;
  color: var(--about-tech-white);
  margin: 0 0 0.25rem;
  letter-spacing: 0.02em;
}

.node-desc {
  font-family: var(--about-font-body);
  font-size: 0.9375rem;
  color: #ccc;
  margin: 0;
  line-height: 1.5;
}

.timeline-svg {
  display: block;
  margin: 0 auto;
}

/* 右侧解读区 */
.about-insight {
  background-color: var(--about-tech-white);
  border: 1px solid var(--about-soft-purple);
  padding: 1.5rem;
  border-radius: 0.5rem;
  box-shadow: 0 2px 8px rgba(0, 51, 102, 0.08);
}

.insight-breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--about-font-body);
  font-size: 0.875rem;
  color: var(--about-deep-space-gray);
  margin-bottom: 0.75rem;
}

.insight-breadcrumb a {
  color: var(--about-electric-purple);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--about-transition), color var(--about-transition);
}

.insight-breadcrumb a:hover,
.insight-breadcrumb a:focus {
  border-bottom-color: var(--about-electric-purple);
  color: var(--about-deep-blue);
}

.breadcrumb-sep {
  color: var(--about-deep-space-gray);
  opacity: 0.6;
}

.insight-h1 {
  font-family: var(--about-font-heading);
  font-weight: 700;
  font-size: 2.25rem;
  color: var(--about-deep-blue);
  margin: 0.25rem 0 0.5rem;
  letter-spacing: -0.02em;
  line-height: 1.1;
}

.insight-intro {
  font-family: var(--about-font-body);
  font-size: 1.125rem;
  color: var(--about-deep-space-gray);
  line-height: 1.6;
  margin: 0 0 2rem;
  max-width: 48em;
}

.insight-block {
  margin-bottom: 2.5rem;
}

.block-numbered {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--about-font-heading);
  font-weight: 700;
  font-size: 1.5rem;
  color: var(--about-deep-blue);
  margin: 0 0 1rem;
  border-bottom: 2px solid var(--about-electric-purple);
  padding-bottom: 0.5rem;
}

.number-badge {
  background-color: var(--about-electric-purple);
  color: #fff;
  font-family: var(--about-font-data);
  font-weight: 700;
  font-size: 1rem;
  padding: 0.25rem 0.6rem;
  border-radius: 0.25rem;
}

.block-body {
  font-family: var(--about-font-body);
  font-size: 1rem;
  color: #333;
  line-height: 1.7;
  margin-bottom: 1rem;
}

.block-body p {
  margin: 0 0 0.75rem;
}

.block-visual img {
  width: 100%;
  height: auto;
  max-width: 100%;
  display: block;
  border: 1px solid var(--about-soft-purple);
  border-radius: 0.25rem;
}

.milestone-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

.milestone-card {
  background-color: var(--about-deep-blue);
  padding: 1rem;
  border-radius: 0.375rem;
  border-left: 4px solid var(--about-vibrant-orange);
}

.milestone-label {
  display: inline-block;
  background-color: var(--about-vibrant-orange);
  color: #fff;
  font-family: var(--about-font-data);
  font-weight: 700;
  font-size: 0.8125rem;
  padding: 0.2rem 0.5rem;
  border-radius: 0.25rem;
  margin-bottom: 0.5rem;
}

.milestone-card p {
  font-family: var(--about-font-body);
  font-size: 0.9375rem;
  color: var(--about-tech-white);
  margin: 0;
  line-height: 1.5;
}

.team-visual img {
  width: 100%;
  height: auto;
  max-width: 100%;
  display: block;
  border: 1px solid var(--about-soft-purple);
  border-radius: 0.375rem;
}

/* 桌面 ≥768px 左右分屏 */
@media (min-width: 768px) {
  .page-about-grid {
    grid-template-columns: 1fr 1.2fr;
    gap: 2.5rem;
    padding: 2rem;
    align-items: start;
  }

  .insight-h1 {
    font-size: 2.75rem;
  }

  .milestone-grid {
    grid-template-columns: 1fr 1fr 1fr;
  }

  .timeline-node {
    padding: 1rem;
    gap: 1.25rem;
  }

  .node-heading {
    font-size: 1.25rem;
  }

  .node-desc {
    font-size: 1rem;
  }
}

/* 大桌面 增大留白 */
@media (min-width: 1024px) {
  .page-about-grid {
    padding: 2.5rem 2rem;
  }

  .about-timeline {
    padding: 2rem;
  }

  .about-insight {
    padding: 2rem;
  }
}

/* 确保图片在移动端不溢出 */
img {
  max-width: 100%;
  height: auto;
  object-fit: cover;
}