/* page-about 专属 */
.page-about {
  --page-bg: #FFFFFF;
  --page-section-bg: #F5F5F5; /* 银灰 */
  --page-section-alt-bg: #E8F5E9; /* 草绿浅阶 */
  --page-tag-bg: #C8E6C9;
  --page-tag-color: #1B5E20;
  --page-card-shadow: 0 2px 8px rgba(0,0,0,0.08);
  --page-card-lift: 0 8px 24px rgba(0,0,0,0.12);
  background: var(--page-bg);
  color: var(--color-dark);
  font-family: var(--font-body);
  line-height: 1.6;
}

/* 面包屑 */
.page-about .breadcrumb {
  padding: 1rem var(--container-padding, 1rem);
  font-size: var(--size-small);
  color: var(--color-gray);
}
.page-about .breadcrumb__link {
  color: var(--color-primary);
  text-decoration: underline;
}
.page-about .breadcrumb__sep {
  margin: 0 0.4em;
}
.page-about .breadcrumb__current {
  font-weight: var(--weight-bold);
}

/* 页面标题 */
.page-about .page-title {
  font-family: var(--font-heading);
  font-weight: var(--weight-bold);
  font-style: italic;
  font-size: var(--size-title1);
  padding: 0 var(--container-padding, 1rem);
  margin-top: 0.5rem;
  margin-bottom: 1.5rem;
  border-left: 4px solid var(--color-accent);
  padding-left: 0.75rem;
}

/* 章节基础 */
.page-about .section {
  padding: 2rem var(--container-padding, 1rem);
  background: var(--page-section-bg);
  box-shadow: inset 0 1px 0 rgba(0,0,0,0.05), 0 1px 3px rgba(0,0,0,0.03);
  position: relative;
  margin-bottom: 2px;
}
.page-about .section--alt {
  background: var(--page-section-alt-bg);
}
.page-about .section__head {
  margin-bottom: 1rem;
  position: relative;
}
.page-about .section__tag {
  display: inline-block;
  background: var(--page-tag-bg);
  color: var(--page-tag-color);
  font-size: var(--size-small);
  font-weight: var(--weight-bold);
  font-family: var(--font-mono);
  padding: 0.2em 0.8em;
  border-radius: 0 2px 2px 0;
  position: relative;
  left: calc(-1 * var(--container-padding, 1rem));
  box-shadow: 0 1px 2px rgba(0,0,0,0.1);
}
.page-about .section__tag::after {
  content: "";
  position: absolute;
  top: 0;
  right: -0.5em;
  width: 0.5em;
  height: 100%;
  background: var(--page-tag-bg);
  clip-path: polygon(0 0, 100% 50%, 0 100%);
}
.page-about .section__body {
  max-width: 72ch;
}
.page-about .section-title {
  font-family: var(--font-heading);
  font-weight: var(--weight-bold);
  font-style: italic;
  font-size: var(--size-title2);
  margin-bottom: 1rem;
  color: var(--color-dark);
}
.page-about .section__desc {
  font-size: var(--size-body);
  color: var(--color-gray);
  margin-bottom: 1.5rem;
}

/* 图片 */
.page-about .section__image {
  margin: 1.5rem 0 0;
  max-width: 100%;
}
.page-about .section__image img {
  max-width: 100%;
  height: auto;
  object-fit: contain;
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
}
.page-about .image-hero {
  display: block;
}

/* 功能网格 – 卡片 */
.page-about .feature-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
  margin-bottom: 1.5rem;
}
.page-about .card {
  background: var(--color-light);
  border: 1px solid var(--color-secondary);
  border-radius: var(--radius);
  padding: 1.25rem;
  box-shadow: var(--shadow-card);
  transition: box-shadow var(--transition-fast), transform var(--transition-fast);
  cursor: default;
  position: relative;
}
.page-about .card:hover,
.page-about .card:focus-within {
  box-shadow: var(--shadow-lift);
  transform: translateY(-2px);
}
.page-about .card__title {
  font-family: var(--font-heading);
  font-weight: var(--weight-bold);
  font-size: 1.2rem;
  margin-bottom: 0.5rem;
}
.page-about .card__text {
  font-size: var(--size-body);
  color: var(--color-gray);
}
.page-about .card__detail {
  display: none;
  position: absolute;
  bottom: calc(100% + 0.5rem);
  left: 0;
  right: 0;
  background: var(--color-dark);
  color: var(--color-light);
  font-size: var(--size-small);
  padding: 0.75rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow-lift);
  z-index: 10;
}
.page-about .card:hover .card__detail,
.page-about .card:focus-within .card__detail {
  display: block;
}

/* 内部链接区域 */
.page-about .internal-links {
  padding: 2rem var(--container-padding, 1rem);
  background: var(--color-secondary);
  text-align: center;
}
.page-about .internal-links .section-title {
  margin-bottom: 1rem;
}
.page-about .link-list {
  list-style: none;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1.5rem;
}
.page-about .link-primary {
  font-family: var(--font-heading);
  font-weight: var(--weight-bold);
  color: var(--color-primary);
  text-decoration: underline;
  font-size: var(--size-body);
  transition: color var(--transition-fast);
}
.page-about .link-primary:hover {
  color: var(--color-accent);
}

/* 滚动淡入效果 (渐进增强) */
[data-scroll-section] {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
[data-scroll-section][data-visible] {
  opacity: 1;
  transform: translateY(0);
}

/* 移动端优先：容器 */
.page-about .container {
  max-width: 100%;
  margin: 0 auto;
  --container-padding: 1rem;
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
}

/* 桌面端 */
@media (min-width: 768px) {
  .page-about {
    --container-padding: 2rem;
  }
  .page-about .container {
    max-width: 1200px;
  }
  .page-about .page-title {
    font-size: calc(var(--size-title1) * 1.2);
    padding-left: 1.25rem;
    border-left-width: 6px;
  }
  .page-about .feature-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .page-about .section__tag {
    left: -1.5rem;
  }
  .page-about .section__image {
    max-width: 80%;
  }
}

@media (min-width: 1024px) {
  .page-about .section__body {
    display: flex;
    flex-wrap: wrap;
    align-items: flex-start;
    gap: 2rem;
  }
  .page-about .section__body > :not(.section__image) {
    flex: 1 1 50%;
    min-width: 300px;
  }
  .page-about .section__body .section__image {
    flex: 1 1 40%;
    margin-top: 0;
  }
}