.modal {
    display:    none;
    position:   fixed;
    z-index:    1000;
    top:        0;
    left:       0;
    height:     100%;
    width:      100%;
    background: rgba( 255, 255, 255, .8 )
    url('https://i.stack.imgur.com/FhHRx.gif')
    50% 50%
    no-repeat;
}
body.loading {
    overflow: hidden;
}
body.loading .modal {
    display: block;
}

body {
  background-color: #e1e1e1;
}