.page-about {
  --page-bg: #1A1A1A;
  --page-content-bg: #F5F5F5;
  --page-primary: #FF4500;
  --page-primary-hover: #E03D00;
  --page-dark: #1A1A1A;
  --page-text-dark: #1A1A1A;
  --page-text-light: #F5F5F5;
  --page-index-size: 80px;
  --page-heading-size: 32px;
  --page-body-size: 16px;
  --page-radius: 12px;
  --page-transition: 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  max-width: 1200px;
  margin: 0 auto;
  padding: 24px 16px 60px;
  font-family: 'Helvetica Neue', '微软雅黑', sans-serif;
  font-weight: 300;
  font-size: var(--page-body-size);
  line-height: 1.6;
  color: var(--page-text-dark);
  background: var(--page-bg);
  min-height: 80vh;
}

/* 面包屑 */
.page-about .about-breadcrumb {
  font-family: 'Helvetica Neue', '黑体', sans-serif;
  font-weight: 200;
  font-size: 12px;
  letter-spacing: 0.05em;
  color: #CCCCCC;
  margin-bottom: 16px;
  padding: 8px 0;
}
.page-about .about-breadcrumb a {
  color: #CCCCCC;
  text-decoration: none;
  transition: color var(--page-transition);
}
.page-about .about-breadcrumb a:hover {
  color: var(--page-primary);
}
.page-about .about-breadcrumb__sep {
  margin: 0 8px;
  color: #666666;
}
.page-about .about-breadcrumb [aria-current="page"] {
  color: var(--page-primary);
}

/* 页面主标题 */
.page-about .about-title {
  font-family: 'Helvetica Neue', '黑体', sans-serif;
  font-weight: 100;
  font-size: 40px;
  letter-spacing: -0.02em;
  line-height: 1.1;
  color: var(--page-primary);
  margin: 0 0 40px;
  padding: 0 0 16px;
  border-bottom: 2px solid rgba(255, 69, 0, 0.25);
}

/* 章节容器 */
.page-about .about-chapter {
  display: flex;
  flex-direction: column;
  margin-bottom: 32px;
  border-radius: var(--page-radius);
  overflow: hidden;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.35);
  transition: box-shadow var(--page-transition);
}
.page-about .about-chapter:hover {
  box-shadow: 0 8px 32px rgba(255, 69, 0, 0.20);
}

/* 数字索引区 */
.page-about .about-chapter__index {
  background: var(--page-dark);
  padding: 28px 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--page-transition), transform var(--page-transition);
}
.page-about .about-chapter:hover .about-chapter__index {
  background: #222;
}
.page-about .about-chapter__index span {
  font-family: 'Arial', 'Helvetica', sans-serif;
  font-weight: 800;
  font-size: var(--page-index-size);
  color: var(--page-primary);
  line-height: 1;
  letter-spacing: -0.04em;
  transition: transform var(--page-transition), color var(--page-transition);
  display: inline-block;
}
.page-about .about-chapter__index span:hover {
  transform: scale(1.10);
  color: #FF6600;
}

/* 内容区 */
.page-about .about-chapter__content {
  background: var(--page-content-bg);
  padding: 28px 20px 32px;
  transition: background var(--page-transition);
}

/* 章节标题 */
.page-about .about-chapter__heading {
  font-family: 'Helvetica Neue', '黑体', sans-serif;
  font-weight: 100;
  font-size: var(--page-heading-size);
  letter-spacing: -0.02em;
  line-height: 1.2;
  color: var(--page-dark);
  margin: 0 0 16px;
  position: relative;
  padding-left: 0;
}
.page-about .about-chapter__heading::after {
  content: '';
  display: block;
  width: 48px;
  height: 3px;
  background: var(--page-primary);
  margin-top: 8px;
  border-radius: 2px;
  transition: width var(--page-transition);
}
.page-about .about-chapter:hover .about-chapter__heading::after {
  width: 72px;
}

/* 正文 */
.page-about .about-chapter__text {
  font-size: var(--page-body-size);
  font-weight: 300;
  color: #333;
  margin: 0 0 20px;
  max-width: 720px;
}

/* 图片 */
.page-about .about-chapter__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  margin: 0 0 20px;
  object-fit: cover;
  aspect-ratio: 600 / 400;
  background: #E0E0E0;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
  transition: opacity var(--page-transition), transform var(--page-transition);
}
.page-about .about-chapter:hover .about-chapter__img {
  opacity: 0.92;
  transform: scale(1.01);
}

/* 链接组 */
.page-about .about-chapter__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 4px;
}
.page-about .about-chapter__link {
  display: inline-block;
  font-family: 'Helvetica Neue', '黑体', sans-serif;
  font-weight: 500;
  font-size: 14px;
  letter-spacing: 0.02em;
  color: var(--page-primary);
  background: transparent;
  border: 1.5px solid var(--page-primary);
  border-radius: 30px;
  padding: 8px 22px;
  text-decoration: none;
  transition: background var(--page-transition), color var(--page-transition), transform var(--page-transition);
}
.page-about .about-chapter__link:hover {
  background: var(--page-primary);
  color: #fff;
  transform: translateY(-2px);
}

/* 桌面端 ≥768px */
@media (min-width: 768px) {
  .page-about {
    padding: 32px 32px 80px;
  }
  .page-about .about-title {
    font-size: 56px;
    margin-bottom: 56px;
  }
  .page-about .about-chapter {
    flex-direction: row;
    margin-bottom: 48px;
    border-radius: 0;
    box-shadow: none;
    position: relative;
  }
  .page-about .about-chapter:hover {
    box-shadow: none;
  }

  /* 数字索引区 - 宽屏斜切 */
  .page-about .about-chapter__index {
    width: 30%;
    padding: 64px 32px;
    clip-path: polygon(0 0, 85% 0, 100% 100%, 0 100%);
    justify-content: center;
    align-items: center;
    position: relative;
    z-index: 1;
  }
  .page-about .about-chapter__index span {
    font-size: 120px;
  }
  .page-about .about-chapter:hover .about-chapter__index {
    transform: translateX(4px);
  }

  /* 内容区 */
  .page-about .about-chapter__content {
    width: 70%;
    padding: 48px 40px 56px;
    margin-left: -4%;
    position: relative;
    z-index: 2;
    border-radius: 0 12px 12px 0;
  }
  .page-about .about-chapter__heading {
    font-size: 38px;
  }
  .page-about .about-chapter__text {
    font-size: 17px;
  }

  /* 反向章节：数字在右，内容在左 */
  .page-about .about-chapter--reverse {
    flex-direction: row-reverse;
  }
  .page-about .about-chapter--reverse .about-chapter__index {
    clip-path: polygon(15% 0, 100% 0, 100% 100%, 0% 100%);
  }
  .page-about .about-chapter--reverse .about-chapter__index span {
    transform-origin: center;
  }
  .page-about .about-chapter--reverse .about-chapter__content {
    margin-left: 0;
    margin-right: -4%;
    border-radius: 12px 0 0 12px;
  }
  .page-about .about-chapter--reverse:hover .about-chapter__index {
    transform: translateX(-4px);
  }

  /* 图片在宽屏下保持比例 */
  .page-about .about-chapter__img {
    max-width: 90%;
    margin-left: 0;
    margin-right: auto;
  }
  .page-about .about-chapter--reverse .about-chapter__img {
    margin-left: auto;
    margin-right: 0;
  }
}

/* 大桌面端 ≥1024px */
@media (min-width: 1024px) {
  .page-about {
    padding: 40px 48px 100px;
  }
  .page-about .about-title {
    font-size: 64px;
  }
  .page-about .about-chapter__index {
    width: 28%;
  }
  .page-about .about-chapter__index span {
    font-size: 140px;
  }
  .page-about .about-chapter__content {
    width: 72%;
    padding: 60px 56px 64px;
  }
  .page-about .about-chapter__heading {
    font-size: 42px;
  }
  .page-about .about-chapter__text {
    font-size: 18px;
    max-width: 620px;
  }
  .page-about .about-chapter__img {
    max-width: 80%;
  }
}