.day {
    position: fixed;
    z-index: -100;
    width: 100vw;
    height: 100vh;
    background: radial-gradient(circle at top right, rgba(255, 255, 224, 0.6), rgba(255, 255, 224, 0) 50%), linear-gradient(to bottom, #87CEEB, #87CEEB 30%, #FFFFFF 70%, #FFFFFF 100%);

  }

  .cloud {
    position: absolute;
    background: #ffffff;
    border-radius: 50%;
    box-shadow: 0 0 20px 20px #ffffff;
    opacity: 0.8;
    animation: float-c 10s linear infinite;
    z-index: 0;
  }
  .cloud1 {
    width: 250px;
    height: 70px;
    top: 20%;
    left: -250px;
    animation-delay: 0s;
  }
  
  .cloud2 {
    width: 150px;
    height: 50px;
    top: 40%;
    left: -150px;
    animation-delay: 4s;
  }
  
  @keyframes float-c {
    0% {
        transform: translateX(0);
    }
    100% {
        transform: translateX(130vw);
    }
  }

  @keyframes drift {
    from { background-position: 0 0, 0 200px; }
    to { background-position: 100% 0, 100% 200px; }
  }

.night{
    position: fixed;
    z-index: -100;
    width: 100vw;
    height: 100vh;
    background: linear-gradient(45deg, #767574, #794545, #1f1120, #151805);

}

.star {
    position: absolute;
    width: 2px;
    height: 2px;
    background: white;
    border-radius: 50%;
    animation: twinkle 2s infinite ease-in-out;
  }
  @keyframes twinkle {
    0%, 100% {
        opacity: 0.2;
    }
    50% {
        opacity: 1;
    }
  }
  
  .star:nth-child(1) { top: 10%; left: 20%; animation-delay: 0s; }
          .star:nth-child(2) { top: 30%; left: 40%; animation-delay: 0.5s; }
          .star:nth-child(3) { top: 50%; left: 60%; animation-delay: 1s; }
          .star:nth-child(4) { top: 70%; left: 80%; animation-delay: 1.5s; }
          .star:nth-child(5) { top: 20%; left: 70%; animation-delay: 2s; }
          .star:nth-child(6) { top: 40%; left: 30%; animation-delay: 2.5s; }
          .star:nth-child(7) { top: 60%; left: 50%; animation-delay: 3s; }
          .star:nth-child(8) { top: 80%; left: 10%; animation-delay: 3.5s; }
          .star:nth-child(9) { top: 15%; left: 25%; animation-delay: 4s; }
          .star:nth-child(10) { top: 35%; left: 45%; animation-delay: 4.5s; }
          .star:nth-child(11) { top: 55%; left: 65%; animation-delay: 5s; }
          .star:nth-child(12) { top: 75%; left: 85%; animation-delay: 5.5s; }
          .star:nth-child(13) { top: 25%; left: 75%; animation-delay: 6s; }
          .star:nth-child(14) { top: 45%; left: 35%; animation-delay: 6.5s; }
  


  .line{
    transform-origin: center top;
    position: fixed;
    top: 0;
    right: 4vw;
    height: 60vh;
    width: 0.5vw;
    background-color: #000;
    z-index: 1000;
    cursor: pointer; /* 添加指针，表示可点击 */
    transition: height 1s ease; /* 平滑过渡效果 */
    animation: roll 1.5s infinite alternate; 
    border-radius: 50%; /* 圆角效果 */
    box-shadow: 
      0 0 5px rgba(0, 0, 0, 0.5), /* 阴影效果 */
      inset 0 0 5px rgba(255, 255, 255, 0.3); /* 内部阴影效果 */
  }
  .line::after{
    content: '';
    background-image: url('http://q2.qlogo.cn/headimg_dl?dst_uin=2041584846&spec=100');
    background-size: cover; /* 确保背景图片覆盖整个伪元素 */
    
    position: absolute;
    transition: 1s ease; /* 平滑过渡效果 */
    bottom: -2.5vw;
    right: -2.5vw;
    width: 5vw;
    height: 5vw;
    border-radius: 50%;
    border: 2px solid black;
    box-shadow: 0 0 5vh rgba(0, 0, 0, 0.5), inset 0 0 5px rgba(255, 255, 255, 0.3);
    animation: flowShadow 1s linear infinite;
  }

 


  .line.collapsed{
    height: 10vh;
  }
  @keyframes roll {
    0%  {
  
      transform:  rotate(-3deg);
  
      
    }
    100% {
  
      transform:  rotate(16deg);
  
      
    }
  }
  
  @keyframes flowShadow{
    0%, 100% {
      border-color: #4B0082; /* 深紫色 */
      box-shadow: 0 0 10px #4B0082, 0 0 20px #4B0082, 0 0 30px #4B0082; /* 深紫色阴影 */
    }
    50% {
      border-color: #8A2BE2; /* 亮紫色 */
      box-shadow: 0 0 10px #8A2BE2, 0 0 20px #8A2BE2, 0 0 30px #8A2BE2; /* 亮紫色阴影 */
    }
  }