.page-about {
  --about-accent-line: rgba(230, 57, 70, 0.25);
  --about-timeline-width: 3px;
  --about-dot-size: 14px;
  --about-transition: 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  --about-gap: 3rem;
  --about-sidebar-max: 520px;

  display: grid;
  grid-template-columns: 1fr minmax(280px, var(--about-sidebar-max));
  gap: var(--about-gap);
  max-width: 1440px;
  margin: 0 auto;
  padding: 2rem 1.5rem 3rem;
  position: relative;
  background: var(--dark-bg, #0B0C10);
  color: var(--text-primary, #FFFFFF);
  min-height: 80vh;
}

/* 面包屑 */
.page-about .breadcrumb {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8125rem;
  font-family: var(--font-body, 'Inter', sans-serif);
  color: var(--text-secondary, #B0BEC5);
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-subtle, rgba(255,255,255,0.08));
  margin-bottom: 2rem;
}
.page-about .breadcrumb a {
  color: var(--metallic-silver, #B0BEC5);
  text-decoration: none;
  transition: color var(--about-transition);
}
.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--primary-red, #E63946);
}
.page-about .breadcrumb .sep {
  color: var(--primary-red, #E63946);
  font-weight: 700;
  margin: 0 0.125rem;
}

/* 左侧主区域 */
.page-about .about-left {
  display: flex;
  flex-direction: column;
  gap: 3.5rem;
}

/* 品牌英雄区 */
.page-about .brand-hero {
  position: relative;
  padding: 1.5rem 0 0.5rem;
}
.page-about .brand-hero .section-number {
  display: block;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  color: var(--primary-red, #E63946);
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  margin-bottom: 0.75rem;
  text-transform: uppercase;
}
.page-about .brand-hero h1 {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-size: 3rem;
  font-weight: 800;
  font-style: italic;
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin: 0 0 0.75rem;
  background: linear-gradient(135deg, #FFFFFF 40%, var(--primary-red, #E63946) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.page-about .brand-subtitle {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--metallic-silver, #B0BEC5);
  font-family: var(--font-body, 'Inter', sans-serif);
  letter-spacing: 0.08em;
  margin: 0 0 1.25rem;
  text-transform: uppercase;
}
.page-about .brand-desc {
  font-size: 1rem;
  line-height: 1.7;
  color: var(--text-secondary, #B0BEC5);
  font-family: var(--font-body, 'Inter', sans-serif);
  max-width: 580px;
  margin: 0 0 1.75rem;
}
.page-about .brand-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}
.page-about .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 2rem;
  font-size: 0.9375rem;
  font-weight: 600;
  font-family: var(--font-body, 'Inter', sans-serif);
  border: none;
  border-radius: 4px;
  background: linear-gradient(135deg, var(--primary-red, #E63946), var(--secondary-blue, #1D3557));
  color: #fff;
  text-decoration: none;
  cursor: pointer;
  transition: box-shadow var(--about-transition), transform var(--about-transition);
  position: relative;
  z-index: 1;
}
.page-about .btn:hover,
.page-about .btn:focus-visible {
  box-shadow: 0 0 24px var(--glow-red, rgba(230,57,70,0.4));
  transform: translateY(-2px);
}
.page-about .btn-outline {
  background: transparent;
  border: 1px solid var(--primary-red, #E63946);
  color: var(--primary-red, #E63946);
}
.page-about .btn-outline:hover,
.page-about .btn-outline:focus-visible {
  background: rgba(230, 57, 70, 0.08);
  box-shadow: 0 0 20px var(--glow-red, rgba(230,57,70,0.25));
}

/* 通用章节编号 */
.page-about .section-number {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  color: var(--primary-red, #E63946);
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  margin-bottom: 0.5rem;
}

/* 使命章节 */
.page-about .mission-section h2,
.page-about .milestone-section h2,
.page-about .contact-section h2 {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-size: 2rem;
  font-weight: 700;
  font-style: italic;
  line-height: 1.2;
  margin: 0 0 1rem;
  color: var(--text-primary, #FFFFFF);
}
.page-about .mission-section p {
  font-size: 1rem;
  line-height: 1.75;
  color: var(--text-secondary, #B0BEC5);
  font-family: var(--font-body, 'Inter', sans-serif);
  max-width: 620px;
  margin: 0 0 1rem;
}

/* 时间轴 */
.page-about .timeline {
  display: flex;
  flex-direction: column;
  gap: 0;
  position: relative;
  padding-left: 2.25rem;
}
.page-about .timeline::before {
  content: '';
  position: absolute;
  left: 6px;
  top: 12px;
  bottom: 12px;
  width: var(--about-timeline-width);
  background: linear-gradient(to bottom, var(--primary-red, #E63946), var(--secondary-blue, #1D3557), var(--primary-red, #E63946));
  border-radius: 2px;
  opacity: 0.6;
}
.page-about .timeline-item {
  position: relative;
  margin-bottom: 0.5rem;
}
.page-about .timeline-marker {
  display: flex;
  align-items: center;
  gap: 0.875rem;
  padding: 0.875rem 1rem;
  cursor: pointer;
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid transparent;
  transition: background var(--about-transition), border-color var(--about-transition), box-shadow var(--about-transition);
  user-select: none;
}
.page-about .timeline-marker:hover,
.page-about .timeline-marker:focus-visible {
  background: rgba(230, 57, 70, 0.08);
  border-color: var(--about-accent-line);
  box-shadow: 0 0 16px rgba(230, 57, 70, 0.12);
}
.page-about .timeline-dot {
  flex-shrink: 0;
  width: var(--about-dot-size);
  height: var(--about-dot-size);
  border-radius: 50%;
  background: var(--primary-red, #E63946);
  border: 2px solid var(--dark-bg, #0B0C10);
  box-shadow: 0 0 0 2px var(--primary-red, #E63946), 0 0 12px rgba(230, 57, 70, 0.3);
  transition: transform var(--about-transition), box-shadow var(--about-transition);
}
.page-about .timeline-item[data-open] .timeline-dot {
  transform: scale(1.25);
  box-shadow: 0 0 0 3px var(--primary-red, #E63946), 0 0 24px rgba(230, 57, 70, 0.5);
}
.page-about .timeline-version {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--text-primary, #FFFFFF);
  flex: 1;
}
.page-about .timeline-badge {
  font-size: 0.6875rem;
  font-weight: 600;
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  color: var(--primary-red, #E63946);
  background: rgba(230, 57, 70, 0.12);
  padding: 0.2rem 0.6rem;
  border-radius: 3px;
  letter-spacing: 0.04em;
}
.page-about .timeline-content {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows var(--about-transition), padding var(--about-transition), opacity var(--about-transition);
  opacity: 0;
  padding: 0 1rem 0 2.75rem;
  overflow: hidden;
}
.page-about .timeline-item[data-open] .timeline-content {
  grid-template-rows: 1fr;
  opacity: 1;
  padding-top: 0.75rem;
  padding-bottom: 1rem;
}
.page-about .timeline-content > div {
  overflow: hidden;
}
.page-about .timeline-content img {
  width: 200px;
  height: 200px;
  object-fit: cover;
  border-radius: 6px;
  margin-bottom: 0.75rem;
  border: 1px solid var(--border-subtle, rgba(255,255,255,0.08));
  display: block;
}
.page-about .timeline-content p {
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--text-secondary, #B0BEC5);
  font-family: var(--font-body, 'Inter', sans-serif);
  margin: 0;
  max-width: 520px;
}

/* 联系方式 */
.page-about .contact-card {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1.25rem;
  padding: 1.5rem;
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-subtle, rgba(255,255,255,0.08));
  border-radius: 8px;
}
.page-about .contact-item {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding: 0.75rem;
  border-radius: 6px;
  transition: background var(--about-transition);
  cursor: default;
}
.page-about .contact-item[data-copy] {
  cursor: pointer;
}
.page-about .contact-item[data-copy]:hover,
.page-about .contact-item[data-copy]:focus-visible {
  background: rgba(230, 57, 70, 0.06);
}
.page-about .contact-label {
  font-size: 0.6875rem;
  font-weight: 700;
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--primary-red, #E63946);
}
.page-about .contact-value {
  font-size: 1rem;
  font-weight: 500;
  font-family: var(--font-body, 'Inter', sans-serif);
  color: var(--text-primary, #FFFFFF);
  word-break: break-all;
}
.page-about .contact-note {
  font-size: 0.78125rem;
  color: var(--text-secondary, #B0BEC5);
  font-family: var(--font-body, 'Inter', sans-serif);
  margin-top: 0.125rem;
}

/* 底部愿景 */
.page-about .brand-vision {
  position: relative;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--border-subtle, rgba(255,255,255,0.08));
  margin-top: 0.5rem;
}
.page-about .brand-vision img {
  width: 100%;
  height: auto;
  max-height: 400px;
  object-fit: cover;
  display: block;
}
.page-about .vision-text {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 1.25rem 1.5rem;
  margin: 0;
  font-size: 0.9375rem;
  color: #fff;
  background: linear-gradient(to top, rgba(11, 12, 16, 0.92) 40%, transparent);
  font-family: var(--font-body, 'Inter', sans-serif);
  line-height: 1.6;
}

/* 右侧分屏区域 */
.page-about .about-right {
  position: relative;
}
.page-about .right-sticky {
  position: sticky;
  top: 2rem;
  display: flex;
  flex-direction: column;
  gap: 2rem;
}
.page-about .hero-visual {
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--border-subtle, rgba(255,255,255,0.08));
  box-shadow: 0 0 40px rgba(230, 57, 70, 0.08);
}
.page-about .hero-visual img {
  width: 100%;
  height: auto;
  max-height: 800px;
  object-fit: cover;
  display: block;
  aspect-ratio: 1 / 1;
}

/* 品牌速览 */
.page-about .quick-facts {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-subtle, rgba(255,255,255,0.08));
  border-radius: 8px;
  padding: 1.5rem;
}
.page-about .quick-facts h3 {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-size: 1.125rem;
  font-weight: 700;
  font-style: italic;
  margin: 0 0 1rem;
  color: var(--text-primary, #FFFFFF);
  letter-spacing: 0.02em;
}
.page-about .quick-facts ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.page-about .quick-facts li {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.75rem;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border-subtle, rgba(255,255,255,0.06));
}
.page-about .quick-facts li:last-child {
  border-bottom: none;
}
.page-about .fact-label {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-secondary, #B0BEC5);
  font-family: var(--font-body, 'Inter', sans-serif);
  white-space: nowrap;
}
.page-about .fact-value {
  font-size: 0.875rem;
  font-weight: 500;
  text-align: right;
  color: var(--text-primary, #FFFFFF);
  font-family: var(--font-body, 'Inter', sans-serif);
}

/* 移动端优先，窄屏单列 */
@media (max-width: 1023px) {
  .page-about {
    grid-template-columns: 1fr;
    gap: 2rem;
    padding: 1.5rem 1rem 2.5rem;
  }
  .page-about .about-left {
    gap: 2.5rem;
  }
  .page-about .about-right {
    order: -1;
  }
  .page-about .right-sticky {
    position: static;
  }
  .page-about .hero-visual img {
    max-height: 480px;
    aspect-ratio: auto;
  }
  .page-about .brand-hero h1 {
    font-size: 2.25rem;
  }
  .page-about .mission-section h2,
  .page-about .milestone-section h2,
  .page-about .contact-section h2 {
    font-size: 1.625rem;
  }
  .page-about .contact-card {
    grid-template-columns: 1fr;
  }
  .page-about .timeline-content img {
    width: 100%;
    height: auto;
    max-width: 200px;
  }
  .page-about .brand-vision img {
    max-height: 260px;
  }
  .page-about .vision-text {
    position: relative;
    background: rgba(11, 12, 16, 0.95);
    padding: 1rem;
  }
}

@media (max-width: 480px) {
  .page-about {
    padding: 1rem 0.75rem 2rem;
  }
  .page-about .brand-hero h1 {
    font-size: 1.75rem;
  }
  .page-about .brand-actions {
    flex-direction: column;
  }
  .page-about .btn {
    width: 100%;
    justify-content: center;
  }
  .page-about .timeline-marker {
    padding: 0.75rem 0.625rem;
  }
  .page-about .timeline-version {
    font-size: 0.9375rem;
  }
}
</main>