.preloader{
      position: fixed;
      top: 0;
      left: 0;
      height: 100vh;
      width: 100%;
      background-color: #ffffff;
      z-index: 99;
    .loader {
      img{
        position: absolute;
        top: 50%;  
        left: 50%;
        transform: translate(-50%,-50%); 
      }
    }
}