* {
    box-sizing: border-box;
  }

  html {
    /* 开启平滑滚动，点击锚点自动平滑定位 */
    scroll-behavior: smooth; 
  }

  body {
    margin: 0;
    font-family: Arial, "Microsoft YaHei", sans-serif;
    color: #111;
    background: #fff;
  }

  .case-page {
    display: flex;
    max-width: 1500px;
    margin: 0 auto;
    padding: 48px 40px 80px;
    gap: 56px;
  }

  /* 左侧目录 */
  .case-sidebar {
    width: 260px;
    flex-shrink: 0;
    position: sticky;
    top: 40px;
    align-self: flex-start;
  }

  .sidebar-title {
    font-size: 24px;
    font-weight: 400;
    letter-spacing: 0.5px;
    margin-bottom: 6px;
  }

  .sidebar-subtitle {
    font-size: 14px;
    color: #999;
    margin-bottom: 24px;
  }

  .industry-menu {
    border-top: 1px solid #e5e5e5;
  }

  .industry-menu a {
    display: flex;
    justify-content: space-between;
    align-items: center;
    min-height: 46px;
    text-decoration: none;
    color: #555;
    font-size: 15px;
    line-height: 1.4;
    border-bottom: 1px solid #eee;
    transition: all 0.25s ease;
  }

  .industry-menu a::after {
    content: "›"; /* 添加了一个小箭头，也可以去掉 */
    color: #222;
    font-size: 18px;
    font-weight: 300;
  }

  .industry-menu a:hover {
    color: #000;
    padding-left: 8px;
  }

  /* 右侧内容 */
  .case-content {
    flex: 1;
    min-width: 0;
  }

  .page-heading {
    margin-bottom: 55px;
  }

  .page-heading h1 {
    font-size: 24px;
    font-weight: 600;
    letter-spacing: 0.5px;
    margin: 0 0 6px;
  }

  .heading-line {
    height: 1px;
    background: #e5e5e5;
    margin-top: 22px;
  }

  /* Gallery 案例区块 */
  .case-section {
    margin-bottom: 55px;
    /* 定位缓冲距离，防止被顶部遮挡 */
    scroll-margin-top: 60px; 
  }

  .section-title {
    margin-bottom: 36px;
  }

  .section-title h2 {
    font-size: 22px;
    font-weight: 500;
    margin: 0 0 8px;
    text-transform: uppercase;
  }

  .gallery-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
  }

  .gallery-image {
    width: 100%;
    /* 统一比例容器 */
    aspect-ratio: 64 / 45; 
    background: #f3f3f3;
    overflow: hidden;
  }

  .gallery-image img {
    width: 100%;
    height: 100%;
    /* 无论原图什么比例，都会自动裁剪填充，保证不变形 */
    object-fit: cover; 
    display: block;
    transition: transform 0.35s ease;
  }

  .gallery-image:hover img {
    transform: scale(1.03);
  }

  /* 响应式适配 */
  @media (max-width: 1200px) {
    .gallery-grid {
      grid-template-columns: repeat(2, 1fr);
      gap: 22px;
    }
  }

  @media (max-width: 900px) {
    .case-page {
      flex-direction: column;
      padding: 32px 20px 60px;
    }

    .case-sidebar {
      width: 100%;
      position: static;
    }

    .industry-menu {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 0 20px;
    }

    .page-heading {
      margin-bottom: 52px;
    }

    .case-section {
      margin-bottom: 76px;
    }
  }

  @media (max-width: 560px) {
    .industry-menu {
      grid-template-columns: 1fr;
    }

    .gallery-grid {
      grid-template-columns: 1fr;
    }
  }