Loading Indicator

i would like to add a loading indicator gif with a courtain in the background.

So i tried:

.v-loading-indicator {
    position: fixed; /* Occupy whole screen even if scrolled */
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    /* Eat mouse events when visible, doesn't prevent scrolling */
    pointer-events: auto;
    /* Animated with delay to prevent flashing */
    animation: fadein 0.3s ease-out 0.2s normal 1 both;
    z-index: 2147483647;
    background-image: url("preloader.gif");  <<<without this the courtain is visible
@keyframes fadein {
    0% {
        background: rgba(0,0,0,0);
    100% {
        background: rgba(0,0,0,.5); /* Darkens the UI */

my preloager.gif s in the same diretory as the css file. any idea how to get it done?

No one an idea or ist there just no way?