.page-about {
  --page-bg: var(--color-bg);
  --page-accent: var(--color-accent);
  --page-accent-dark: var(--color-accent-dark);
  --page-primary: var(--color-primary);
  --page-text: var(--color-text);
  --page-text-secondary: var(--color-text-secondary);
  --page-border: var(--color-border);
  --page-card-bg: var(--color-card);
  background: var(--page-bg);
  background-image:
    linear-gradient(0deg, transparent 24%, rgba(10,38,71,0.02) 25%, rgba(10,38,71,0.02) 26%, transparent 27%, transparent 74%, rgba(10,38,71,0.02) 75%, rgba(10,38,71,0.02) 76%, transparent 77%),
    linear-gradient(90deg, transparent 24%, rgba(10,38,71,0.02) 25%, rgba(10,38,71,0.02) 26%, transparent 27%, transparent 74%, rgba(10,38,71,0.02) 75%, rgba(10,38,71,0.02) 76%, transparent 77%);
  background-size: 40px 40px;
  padding: 1rem 1rem 2rem;
  min-height: 70vh;
}

.page-about .breadcrumb {
  font: var(--font-mono);
  color: var(--color-text-secondary);
  margin-bottom: 1rem;
}
.page-about .breadcrumb a {
  color: var(--page-accent);
  text-underline-offset: 3px;
}
.page-about .breadcrumb .sep {
  margin: 0 0.5rem;
  color: var(--color-text-secondary);
}

.page-about .page-title {
  font: var(--font-heading);
  font-size: 2.2rem;
  color: var(--page-primary);
  margin: 0 0 2rem;
  border-left: 4px solid var(--page-accent);
  padding-left: 1rem;
}

.page-about .tab-layout {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.page-about .tab-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  border-bottom: 2px solid var(--page-border);
  padding-bottom: 0.75rem;
}

.page-about .tab-link {
  display: inline-block;
  padding: 0.6rem 1.2rem;
  font: var(--font-mono);
  font-weight: 600;
  color: var(--page-text-secondary);
  background: transparent;
  border: 1px solid transparent;
  border-radius: 0;
  text-decoration: none;
  transition: background 0.25s, color 0.25s, border-color 0.25s;
  white-space: nowrap;
}
.page-about .tab-link:focus-visible {
  outline: 2px solid var(--page-accent);
  outline-offset: 2px;
}
.page-about .tab-link:hover {
  color: var(--page-accent-dark);
  border-color: var(--page-accent);
}

.page-about .tab-panels {
  flex: 1;
  position: relative;
}

.page-about .panel {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height 0.45s ease-in-out, opacity 0.45s ease-in-out;
  margin-bottom: 1.5rem;
}

.page-about .panel:target {
  max-height: 2000px;
  opacity: 1;
}

.page-about .panel:not(:target) {
  max-height: 0;
  opacity: 0;
}

.page-about .panel:first-of-type {
  max-height: 2000px;
  opacity: 1;
}

.page-about .hero-img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  margin: 1.5rem 0;
}

.page-about .panel h2 {
  font: var(--font-subheading);
  color: var(--page-primary);
  margin: 0 0 1rem;
}

.page-about .panel p {
  font: var(--font-body);
  color: var(--page-text);
  max-width: 780px;
  margin: 0.75rem 0;
}

.page-about .btn {
  display: inline-block;
  padding: 0.7rem 1.8rem;
  font: var(--font-mono);
  font-weight: 600;
  text-decoration: none;
  background: var(--page-accent);
  color: var(--color-text-on-accent);
  border: 2px solid var(--page-accent);
  transition: background 0.3s, color 0.3s, border-color 0.3s;
  margin-top: 1.2rem;
}
.page-about .btn:hover,
.page-about .btn:focus-visible {
  background: var(--page-accent-dark);
  border-color: var(--page-accent-dark);
}
.page-about .btn-outline {
  background: transparent;
  color: var(--page-accent);
}
.page-about .btn-outline:hover,
.page-about .btn-outline:focus-visible {
  background: var(--page-accent);
  color: var(--color-text-on-accent);
}

/* 核心理念卡片 */
.page-about .pillar-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  margin: 1.5rem 0;
}

.page-about .pillar-card {
  background: var(--page-card-bg);
  border: 2px solid var(--page-accent);
  padding: 1.2rem;
  transition: background 0.35s, box-shadow 0.35s;
  position: relative;
}
.page-about .pillar-card:hover {
  background: var(--page-accent);
  box-shadow: 0 8px 20px rgba(255,107,53,0.18);
}
.page-about .pillar-card:hover .pillar-title,
.page-about .pillar-card:hover .pillar-desc {
  color: var(--color-text-on-accent);
}
.page-about .pillar-card .card-img {
  width: 100%;
  max-width: 300px;
  margin: 0 auto 0.8rem;
}
.page-about .pillar-card .card-img img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
}

.page-about .pillar-title {
  font: var(--font-subheading);
  font-size: 1.4rem;
  margin: 0.5rem 0 0.4rem;
  color: var(--page-primary);
  transition: color 0.25s;
}
.page-about .pillar-desc {
  font: var(--font-body);
  color: var(--page-text-secondary);
  line-height: 1.5;
  transition: color 0.25s;
}

.page-about .pillar-expand {
  cursor: pointer;
  font-size: 0.85rem;
  margin-top: 0.8rem;
  padding: 0.4rem 1rem;
}

.page-about .pillar-detail {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, opacity 0.4s ease;
}
.page-about .pillar-card:focus-within .pillar-detail,
.page-about .pillar-card:hover .pillar-detail {
  max-height: 400px;
  opacity: 1;
}
.page-about .pillar-detail p {
  font: var(--font-body);
  margin-top: 0.8rem;
  border-top: 1px solid var(--page-border);
  padding-top: 0.8rem;
  transition: color 0.25s;
}
.page-about .pillar-card:hover .pillar-detail p {
  color: var(--color-text-on-accent);
}

/* 时间线 */
.page-about .timeline-container {
  position: relative;
  padding: 1.5rem 0;
}
.page-about .timeline-line {
  position: absolute;
  left: 16px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--page-primary);
}

.page-about .timeline-items {
  display: flex;
  flex-direction: column;
  gap: 2rem;
  padding-left: 3rem;
}

.page-about .timeline-item {
  position: relative;
}
.page-about .timeline-dot {
  position: absolute;
  left: -2.2rem;
  top: 0.3rem;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--page-primary);
  border: 2px solid var(--page-bg);
  z-index: 1;
}
.page-about .timeline-item.current .timeline-dot {
  background: var(--page-accent);
  box-shadow: 0 0 0 4px rgba(255,107,53,0.25);
}
.page-about .timeline-item.current .timeline-content {
  border-left: 3px solid var(--page-accent);
  padding-left: 1rem;
}

.page-about .timeline-content {
  padding: 0.2rem 0 0.2rem 1rem;
}
.page-about .timeline-content h3 {
  font: var(--font-subheading);
  font-size: 1.2rem;
  color: var(--page-primary);
  margin: 0 0 0.4rem;
}
.page-about .timeline-content p {
  font: var(--font-body);
  color: var(--page-text-secondary);
  margin: 0;
}
.page-about .timeline-content img {
  width: 100%;
  max-width: 280px;
  height: auto;
  display: block;
  margin: 0.8rem 0;
  object-fit: cover;
}
.page-about .tag-accent {
  background: var(--page-accent);
  color: var(--color-text-on-accent);
  padding: 0.2rem 0.6rem;
  font-size: 0.75rem;
  font-weight: 600;
  display: inline-block;
  vertical-align: middle;
  margin-left: 0.4rem;
}

/* 品牌承诺 */
.page-about .commitment-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 1.8rem;
}

/* 桌面端 */
@media (min-width: 768px) {
  .page-about {
    padding: 1.5rem 2rem 3rem;
  }
  .page-about .page-title {
    font-size: 2.8rem;
  }
  .page-about .tab-layout {
    flex-direction: row;
    gap: 2.5rem;
  }
  .page-about .tab-nav {
    flex-direction: column;
    min-width: 180px;
    border-bottom: none;
    border-right: 2px solid var(--page-border);
    padding-right: 1rem;
    padding-bottom: 0;
    position: sticky;
    top: 130px;
    align-self: flex-start;
    height: fit-content;
  }
  .page-about .tab-link {
    display: block;
    text-align: right;
    padding: 0.75rem 1rem;
    white-space: normal;
  }
  .page-about .pillar-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .page-about .timeline-line {
    left: 24px;
  }
  .page-about .timeline-items {
    padding-left: 3.5rem;
  }
  .page-about .timeline-dot {
    left: -2.6rem;
    width: 14px;
    height: 14px;
  }
  .page-about .timeline-content img {
    max-width: 360px;
  }
  .page-about .tab-panels {
    flex: 1;
    min-width: 0;
  }
}