:root {
      --bg-color: #f9f9f9;
      --text-color: #333;
      --header-bg: white;
      --card-bg: white;
      --footer-bg: #333;
      --footer-text: white;
      --primary: #007BFF;
      --primary-dark: #0056b3;
    }



    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      font-family: 'Inter', sans-serif;
    }

    html {
      scroll-behavior: smooth;
    }

    body {
      background-color: var(--bg-color);
      color: var(--text-color);
      opacity: 0;
      transition: opacity 0.6s ease-in-out, background-color 0.3s;
    }

    body.loaded {
      opacity: 1;
    }

    header {
      background: var(--header-bg);
      padding: 1rem 2rem;
      box-shadow: 0 2px 8px rgba(0,0,0,0.05);
      position: sticky;
      top: 0;
      z-index: 1000;
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
    }

    .menu-toggle {
      display: none;
      font-size: 1.6rem;
      cursor: pointer;
      transition: transform 0.3s ease;
    }

    nav {
      display: flex;
      align-items: center;
      transition: max-height 0.4s ease, opacity 0.4s ease;
    }

    nav a {
      margin-left: 1.5rem;
      text-decoration: none;
      color: var(--text-color);
      font-weight: 500;
      transition: 0.3s;
    }

    nav a:hover,
    nav a.active {
      color: var(--primary);
      border-bottom: 2px solid var(--primary);
      padding-bottom: 2px;
    }

    @media (max-width: 768px) {
      .menu-toggle {
        display: block;
      }

      nav {
        overflow: hidden;
        flex-direction: column;
        width: 100%;
        max-height: 0;
        opacity: 0;
      }

      nav.show {
        max-height: 300px;
        opacity: 1;
      }

      nav a {
        margin: 0.8rem 0;
      }

      header {
        flex-direction: column;
        align-items: flex-start;
      }
    }

    .hero {
      padding: 6rem 2rem;
      background: linear-gradient(to right, #e3f2fd, var(--bg-color));
      text-align: center;
    }

    .hero h1 {
      font-size: 3rem;
      margin-bottom: 1rem;
    }

    .hero p {
      font-size: 1.2rem;
      color: #666;
      max-width: 600px;
      margin: 0 auto 2rem;
    }

    .hero button {
      padding: 0.75rem 2rem;
      background: var(--primary);
      color: white;
      border: none;
      border-radius: 6px;
      font-size: 1rem;
      cursor: pointer;
      transition: background 0.3s, transform 0.2s;
    }

    .hero button i {
      margin-left: 0.5rem;
    }

    .hero button:hover {
      background: var(--primary-dark);
    }

    .hero button:active {
      transform: scale(0.95);
    }

    .products {
      padding: 4rem 2rem;
      max-width: 1000px;
      margin: auto;
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
      gap: 2rem;
    }

    .card {
      background: var(--card-bg);
      border-radius: 10px;
      padding: 1.5rem;
      box-shadow: 0 4px 16px rgba(0,0,0,0.06);
      text-align: center;
      transition: transform 0.3s, box-shadow 0.3s;
    }

    .card:hover {
      transform: translateY(-6px);
      box-shadow: 0 6px 20px rgba(0, 0, 0, 0.1);
    }

    .card img {
      width: 100%;
      height: 180px;
      object-fit: cover;
      border-radius: 8px;
    }

    .card h3 {
      margin: 1rem 0 0.5rem;
    }

    section {
      padding: 4rem 2rem;
      text-align: center;
    }

    section p {
      max-width: 700px;
      margin: 1rem auto;
      color: #555;
    }

    footer {
      background: var(--footer-bg);
      color: var(--footer-text);
      text-align: center;
      padding: 2rem 1rem;
      margin-top: 3rem;
    }

    #toTop {
      position: fixed;
      bottom: 30px;
      right: 30px;
      display: none;
      padding: 12px 15px;
      background: var(--primary);
      color: white;
      border: none;
      border-radius: 50%;
      font-size: 18px;
      cursor: pointer;
      z-index: 999;
    }

    #toTop:hover {
      background: var(--primary-dark);
    }

    .corner-img {
  position: fixed;
  top: 0;
  left: 0;
  width: 100px;   /* 初始宽度，可按需要调整 */
  height: auto;   /* 保持图片比例 */
  z-index: 1000;  /* 确保在上层 */
}

/* 移动端适配 */
@media (max-width: 768px) {
  .corner-img {
    width: 60px;   /* 缩小以适配小屏幕 */
  }
}

    /* 轮播图与模态图样式整合进自定义样式中 */
    .carousel-section {
      padding: 2rem;
      text-align: center;
    }

    .carousel-container {
      position: relative;
      overflow: hidden;
      max-width: 800px;
      margin: auto;
    }

    .carousel-track {
      display: flex;
      transition: transform 0.5s ease-in-out;
      gap: 20px;
      padding: 0 10%;
    }

    .carousel-slide {
      flex: 0 0 80%;
      background: #fff;
      border-radius: 12px;
      box-shadow: 0 6px 20px rgba(0, 0, 0, 0.08);
      overflow: hidden;
      transition: transform 0.3s, box-shadow 0.3s;
    }

    .carousel-slide img {
      width: 100%;
      height: auto;
      display: block;
      cursor: pointer;
    }

    .carousel-slide:hover {
      transform: translateY(-5px);
      box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
    }

    .caption {
      padding: 1rem;
      color: #555;
      font-size: 1rem;
    }

    .modal {
      display: none;
      position: fixed;
      z-index: 1001;
      inset: 0;
      background: rgba(0, 0, 0, 0.7);
      backdrop-filter: blur(8px);
      padding: 60px 20px;
      animation: fadeIn 0.4s ease;
    }

    @keyframes fadeIn {
      from { opacity: 0; }
      to   { opacity: 1; }
    }

    .modal-content {
      display: block;
      margin: auto;
      max-width: 90%;
      max-height: 80vh;
      border-radius: 12px;
      box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
      animation: zoomIn 0.4s ease;
    }

    @keyframes zoomIn {
      from {
        transform: scale(0.85);
        opacity: 0;
      }
      to {
        transform: scale(1);
        opacity: 1;
      }
    }

    #modal-caption {
      text-align: center;
      color: #f0f0f0;
      font-size: 1.1rem;
      margin-top: 1rem;
      letter-spacing: 0.5px;
    }

    .close {
      position: absolute;
      top: 20px;
      right: 25px;
      background: rgba(255, 255, 255, 0.1);
      border-radius: 50%;
      padding: 10px 15px;
      color: white;
      font-size: 30px;
      font-weight: bold;
      cursor: pointer;
      transition: background 0.3s, transform 0.2s;
    }

    .close:hover {
      background: rgba(255, 255, 255, 0.25);
      transform: rotate(90deg);
    }


    .video-container {
      position: relative;
      width: 100%;
      max-width: 800px;
      margin: 20px auto;
      overflow: hidden;
      border-radius: 16px;
      box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
    }

    .video-container video {
      width: 100%;
      height: auto;
      display: block;
    }

    /* 可选：美化视频控制条颜色 */
    video::-webkit-media-controls-panel {
      background-color: rgba(0, 0, 0, 0.7);
    }

    @media (max-width: 500px) {
      .video-container {
        border-radius: 12px;
        margin: 10px;
      }
    }
    .video123 {
       margin: 20px auto;
      padding: 0 16px; /* 左右对称留白 */
      box-sizing: border-box;
    }