.page-about {
  --about-number-size: clamp(2.8rem, 5vw, 4.2rem);
  --about-lead-size: clamp(1.05rem, 1.6vw, 1.25rem);
  --about-gold-line: 3px solid var(--primary-accent);
  --about-card-bg: rgba(26, 60, 42, 0.65);
  --about-card-border: rgba(245, 176, 65, 0.15);
  position: relative;
  padding: 0 1rem 3rem;
  max-width: var(--container-max);
  margin: 0 auto;
  color: var(--text-primary);
  font-family: var(--font-body);
}

/* 面包屑 */
.page-about .breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 1rem 0 0.5rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
}
.page-about .breadcrumb a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}
.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--primary-accent);
}
.page-about .breadcrumb-sep {
  color: var(--divider);
  user-select: none;
}
.page-about .breadcrumb-current {
  color: var(--primary-accent);
  font-weight: 600;
}

/* 页面标题 */
.page-about .page-header {
  padding: 1.5rem 0 2rem;
  border-bottom: 1px solid var(--divider);
  margin-bottom: 2.5rem;
}
.page-about .page-header h1 {
  font-family: var(--font-heading);
  font-size: clamp(2rem, 4.5vw, 3.2rem);
  font-weight: 700;
  letter-spacing: 0.02em;
  margin: 0 0 0.35rem;
  color: var(--text-primary);
}
.page-about .page-subtitle {
  font-size: var(--about-lead-size);
  color: var(--text-secondary);
  margin: 0;
  font-weight: 300;
  letter-spacing: 0.04em;
}

/* 通用章节 */
.page-about .about-section {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  padding: 2.5rem 0;
  position: relative;
}
.page-about .about-section + .about-section {
  border-top: 1px solid var(--divider);
}

/* 金色序号 */
.page-about .section-number {
  font-family: var(--font-heading);
  font-size: var(--about-number-size);
  font-weight: 700;
  color: var(--primary-accent);
  line-height: 1;
  letter-spacing: 0.05em;
  position: relative;
  padding-left: 0.25rem;
}
.page-about .section-number::after {
  content: '';
  display: block;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, var(--primary-accent), transparent);
  margin-top: 0.3rem;
  opacity: 0.6;
}

/* 章节主体 */
.page-about .section-body {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}
.page-about .section-text {
  flex: 1;
}
.page-about .section-text h2 {
  font-family: var(--font-heading);
  font-size: clamp(1.4rem, 2.8vw, 2rem);
  font-weight: 700;
  margin: 0 0 0.75rem;
  color: var(--text-primary);
  letter-spacing: 0.01em;
}
.page-about .lead-text {
  font-size: var(--about-lead-size);
  color: var(--text-secondary);
  line-height: 1.7;
  margin: 0 0 1rem;
}
.page-about .section-figure {
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--surface-card);
  box-shadow: var(--shadow-card);
  flex-shrink: 0;
}
.page-about .section-figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

/* 折叠详情 */
.page-about .fold-detail {
  margin: 0.5rem 0 1rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
}
.page-about .fold-detail summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--primary-accent);
  padding: 0.25rem 0;
  transition: color var(--transition-fast);
  list-style: none;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}
.page-about .fold-detail summary::-webkit-details-marker {
  display: none;
}
.page-about .fold-detail summary::before {
  content: '▸';
  transition: transform var(--transition-fast);
  font-size: 1.1em;
}
.page-about .fold-detail[open] summary::before {
  transform: rotate(90deg);
}
.page-about .fold-detail summary:hover,
.page-about .fold-detail summary:focus-visible {
  color: var(--hover-highlight);
}
.page-about .fold-detail[open] {
  padding-bottom: 0.5rem;
}
.page-about .fold-detail p {
  margin: 0.5rem 0 0;
  line-height: 1.65;
}

/* 数据高亮 + tooltip */
.page-about .data-spotlight {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.55rem 1.1rem;
  background: rgba(245, 176, 65, 0.1);
  border: 1px solid rgba(245, 176, 65, 0.3);
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  cursor: default;
  position: relative;
  margin-top: 0.5rem;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}
.page-about .data-spotlight:hover,
.page-about .data-spotlight:focus-visible {
  background: rgba(245, 176, 65, 0.18);
  border-color: var(--primary-accent);
  outline: none;
}
.page-about .gold-text {
  color: var(--primary-accent);
  font-weight: 700;
}
.page-about .spotlight-tip {
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  background: var(--primary-bg);
  color: var(--text-primary);
  padding: 0.5rem 0.9rem;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  font-weight: 400;
  white-space: nowrap;
  box-shadow: 0 4px 16px rgba(0,0,0,0.5);
  border: 1px solid var(--glass-border);
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.2s ease, transform 0.2s ease;
  transform: translateX(-50%) translateY(4px);
  max-width: 260px;
  white-space: normal;
  text-align: center;
  line-height: 1.4;
}
.page-about .data-spotlight:hover .spotlight-tip,
.page-about .data-spotlight:focus-visible .spotlight-tip {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* 服务网格 */
.page-about .services-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}
.page-about .service-card {
  background: var(--about-card-bg);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  border: 1px solid var(--about-card-border);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.25rem 0.75rem;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}
.page-about .service-card:hover {
  border-color: rgba(245, 176, 65, 0.4);
  box-shadow: 0 0 20px rgba(245, 176, 65, 0.06);
}
.page-about .service-card .card-icon {
  color: var(--primary-accent);
  margin-bottom: 0.5rem;
  opacity: 0.85;
}
.page-about .service-card h3 {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  margin: 0 0 0.3rem;
  color: var(--text-primary);
}
.page-about .service-card > p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin: 0 0 0.4rem;
  line-height: 1.5;
}
.page-about .service-card .fold-detail {
  margin: 0.25rem 0 0;
  font-size: 0.85rem;
}
.page-about .service-card .fold-detail p {
  color: var(--text-secondary);
}

/* 特色列表 */
.page-about .features-list {
  list-style: none;
  padding: 0;
  margin: 0 0 1rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.page-about .feature-item {
  display: flex;
  gap: 0.85rem;
  align-items: flex-start;
  padding: 0.75rem 0.75rem 0.75rem 0;
  border-bottom: 1px solid rgba(245, 176, 65, 0.08);
}
.page-about .feature-item:last-child {
  border-bottom: none;
}
.page-about .feature-badge {
  font-size: 1.5rem;
  line-height: 1;
  flex-shrink: 0;
  margin-top: 0.1rem;
}
.page-about .feature-item strong {
  display: block;
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.2rem;
}
.page-about .feature-item p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* 用户价值柱 */
.page-about .value-pillars {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
  margin: 1.25rem 0 0.75rem;
}
.page-about .pillar {
  background: var(--about-card-bg);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  border: 1px solid var(--about-card-border);
  border-radius: var(--radius-sm);
  padding: 0.9rem 1rem;
  text-align: center;
}
.page-about .pillar .gold-text {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  font-weight: 700;
  display: block;
  margin-bottom: 0.15rem;
}
.page-about .pillar p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* 内部链接导航 */
.page-about .internal-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
  padding: 2.5rem 0 0.5rem;
  border-top: 1px solid var(--divider);
  margin-top: 1rem;
}
.page-about .internal-links .btn {
  padding: 0.6rem 1.6rem;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: 0.03em;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: background var(--transition-fast), color var(--transition-fast), box-shadow var(--transition-fast);
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.page-about .internal-links .btn-primary {
  background: linear-gradient(135deg, var(--primary-accent), #e6a030);
  color: var(--primary-bg);
  border: none;
}
.page-about .internal-links .btn-primary:hover,
.page-about .internal-links .btn-primary:focus-visible {
  box-shadow: 0 0 24px rgba(245, 176, 65, 0.35);
  transform: translateY(-1px);
}
.page-about .internal-links .btn-secondary {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--divider);
}
.page-about .internal-links .btn-secondary:hover,
.page-about .internal-links .btn-secondary:focus-visible {
  border-color: var(--primary-accent);
  color: var(--primary-accent);
  background: rgba(245, 176, 65, 0.06);
}

/* ===== 桌面端 768px+ ===== */
@media (min-width: 768px) {
  .page-about {
    padding: 0 2rem 4rem;
  }
  .page-about .breadcrumb {
    padding: 1.5rem 0 0.5rem;
  }
  .page-about .page-header {
    padding: 2rem 0 3rem;
    margin-bottom: 3.5rem;
  }
  .page-about .page-header h1 {
    font-size: clamp(2.4rem, 5vw, 3.6rem);
  }

  .page-about .about-section {
    flex-direction: row;
    gap: 2rem;
    padding: 3.5rem 0;
  }
  .page-about .section-number {
    writing-mode: vertical-lr;
    text-orientation: mixed;
    font-size: clamp(3rem, 5.5vw, 4.8rem);
    padding-left: 0;
    padding-top: 0.25rem;
    min-width: 2.8rem;
    display: flex;
    align-items: flex-start;
    justify-content: center;
  }
  .page-about .section-number::after {
    width: 2px;
    height: 100%;
    background: linear-gradient(180deg, var(--primary-accent), transparent);
    margin-top: 0;
    margin-left: 0.3rem;
  }

  .page-about .section-body {
    flex-direction: row;
    gap: 2.5rem;
    flex: 1;
    align-items: flex-start;
  }
  .page-about .section-text {
    flex: 1.1;
  }
  .page-about .section-figure {
    flex: 0 0 auto;
    max-width: 48%;
  }
  .page-about .section-figure img {
    height: 100%;
    object-fit: cover;
  }

  .page-about .services-grid {
    grid-template-columns: 1fr 1fr;
    gap: 1.25rem;
    width: 100%;
  }
  .page-about .service-card {
    padding: 1.5rem 1.5rem 1rem;
  }

  .page-about .features-list {
    gap: 1.25rem;
  }
  .page-about .feature-item {
    padding: 0.85rem 0.85rem 0.85rem 0;
  }

  .page-about .value-pillars {
    grid-template-columns: 1fr 1fr 1fr;
    gap: 1rem;
  }
  .page-about .pillar {
    padding: 1rem 0.75rem;
  }

  .page-about .internal-links {
    gap: 1rem;
    padding: 3rem 0 0.5rem;
  }
  .page-about .internal-links .btn {
    padding: 0.7rem 2rem;
    font-size: 1.05rem;
  }
}

/* ===== 宽屏 1024px+ ===== */
@media (min-width: 1024px) {
  .page-about {
    padding: 0 2.5rem 5rem;
  }
  .page-about .about-section {
    gap: 3rem;
    padding: 4rem 0;
  }
  .page-about .section-body {
    gap: 3.5rem;
  }
  .page-about .section-figure {
    max-width: 42%;
  }
  .page-about .section-text h2 {
    font-size: clamp(1.6rem, 3vw, 2.2rem);
  }
  .page-about .services-grid {
    gap: 1.5rem;
  }
}

/* ===== 减少动效 ===== */
@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
  .page-about .spotlight-tip {
    transition: none;
  }
  .page-about .data-spotlight:hover .spotlight-tip,
  .page-about .data-spotlight:focus-visible .spotlight-tip {
    transform: translateX(-50%) translateY(0);
  }
}