body, html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    font-family: Arial, sans-serif;
    background-image: url('//www.edingxin.cn/img/beijing.jpg'); 
    background-size: cover;
    background-position: center;
  }
  .container {
    position: relative;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: flex-start; 
    align-items: center;
    padding-bottom: 60px; 
  }
  .header {
    text-align: center;
    margin-bottom: 10px;
    z-index: 5; 
    position: relative;
    width: 100%; 
    color: white;
    padding: 20px 0; 
  }
  .header h1 {
    font-size: 28px;
    color: #999999;
    margin: 0;
  }
  .header p {
    font-size: 12px;
    color: #999999;
    margin: 0;
  }
.header-spacer {
    height: 10px; 
  }
  .content-box {
    background-color: rgba(255, 255, 255, 0.9); 
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    max-width: 1200px;
    width: calc(100% - 40px); 
    margin-bottom: 20px; 
  }
  .grid-container {
    display: grid;
    grid-template-columns: repeat(5, 1fr); 
    gap: 20px;
  }
  .grid-item {
    position: relative;
    padding: 30px;
    min-height: 200px; 
    color: white;
    text-align: center;
    background-size: 200% 200%;
    background-position: center;
    transition: background-position 0.5s ease, box-shadow 0.3s ease;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1); 
    border-radius: 10px; 
  }

  @keyframes randomGradient {
    0% {
      background-position: 0% 50%;
    }
    25% {
      background-position: 100% 50%;
    }
    50% {
      background-position: 0% 100%;
    }
    75% {
      background-position: 100% 0%;
    }
    100% {
      background-position: 50% 50%;
    }
  }
  .grid-item:hover {
    animation: randomGradient 2s infinite;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
  }
  .icon {
    position: absolute;
    top: 10px;
    right: 10px;
    width: 40px;
    height: 40px;
  }
  .text h2 {
    font-size: 24px;
    margin-bottom: 10px;
  }

  .text h2::first-letter {
    font-size: 36px;
    font-weight: bold;
  }
  .text p {
    font-size: 16px;
  }
  .grid-link {
    display: block;
    text-decoration: none;
    color: inherit;
  }
  footer {
    width: 100%;
    text-align: center;
    padding: 10px 0;
    color: #999999;
  }
  footer a {
    color: #999999; 
    text-decoration: none; 
  }
  footer a:hover {
    text-decoration: underline; 
  }

  .modal {
    display: none;
    position: fixed; 
    z-index: 1000; 
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0, 0, 0, 0.4); 
  }
  .modal-content {
    background-color: #fefefe;
    margin: 15% auto; 
    padding: 20px;
    border: 1px solid #888;
    width: 80%; 
    max-width: 600px; 
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    position: relative; 
  }
  .modal h2 {
    margin-top: 0;
  }
  .modal button {
    display: block;
    width: 100%;
    padding: 10px;
    margin-top: 10px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 18px;
    color: white;
    transition: background-color 0.3s;
  }
  .modal button:hover {
    opacity: 0.8;
  }
  .modal .slot-aluminum {
    background-image: linear-gradient(to right, #ff6b6b, #fda085);
  }
  .modal .angle-aluminum {
    background-image: linear-gradient(to right, #6c5ce7, #e056fd);
  }
  .modal .inner-arc {
    background-image: linear-gradient(to right, #ff9ff3, #5d4157);
  }
  .modal .outer-cylinder {
    background-image: linear-gradient(to right, #00c6fb, #005bea);
  }
  .modal .send-wind1 {
    background-image: linear-gradient(to right, #00b09b, #96c93d);
  }
  .modal .return-wind1 {
    background-image: linear-gradient(to right, #83a4d4, #b6fbff);
  }
  .modal .send-wind2 {
    background-image: linear-gradient(to right, #fbc2eb, #a6c1ee);
  }
  .modal .return-wind2 {
    background-image: linear-gradient(to right, #48dbfb, #29cdff);
  }
  .modal .send-wind3 {
    background-image: linear-gradient(to right, #ff6b81, #fcb045);
  }
  .modal .return-wind3 {
    background-image: linear-gradient(to right, #a1c4fd, #c2e9fb);
  }
  .close-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    background-color: #ccc;
    border: none;
    border-radius: 50%;
    padding: 5px;
    cursor: pointer;
    font-size: 18px;
    line-height: 1;
  }
  .close-btn:hover {
    background-color: #aaa;
  }
 
  @media (max-width: 768px) {
    .header h1 {
      font-size: 24px;
    }
    .header p {
      font-size: 14px;
    }
    .grid-container {
      grid-template-columns: repeat(2, 1fr); 
      gap: 10px;
    }
    .grid-item {
      padding: 20px;
      min-height: 150px;
      flex-basis: 100%; 
    }
    .text h2 {
      font-size: 20px;
    }
    .text h2::first-letter {
      font-size: 28px;
    }
    .text p {
      font-size: 14px;
    }
    .icon {
      width: 30px;
      height: 30px;
    }
    .content-box {
      width: calc(100% - 40px); 
      padding: 15px; 
    }
    footer p {
      font-size: 12px;
    }
    .modal-content {
      margin: 20% auto;
      width: 90%; 
    }
  }

.bottom-nav {
    display: flex;
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background: #fff;
    box-shadow: 0 -2px 5px rgba(0,0,0,.1);
    z-index: 1000;
    padding: 10px 0;
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    flex: 1;
    text-decoration: none;
    color: #333;
    gap: 5px;
}

.nav-item img {
    height: 24px;
    width: auto;
}

.nav-item span {
    font-size: 12px;
}

.no-text img {
    height: 58.4px;
    width: auto;
}

.no-text span {
    display: none;
}