.loader {
    position: absolute;
    left: 50%;
    top: 50%;
    z-index: 1;
    width: 400px;
    height: 400px;
    margin: -200px 0 0 -200px;
    border: 50px solid #f3f3f3;
    border-radius: 50%;
    border-top: 50px solid seagreen;
    /*width: 120px;
    height: 120px;*/
    -webkit-animation: spin 2s linear infinite;
    animation: spin 2s linear infinite;
  }
  
  
  @keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
  }