html,
body {
    margin: 0;
    overflow: hidden;
    height: 100%;
}

@keyframes loading-animation {
    0%   {background-image:url("../img/603qm_herz_1.svg"); background-size: 50px 50px;}
    20%  {background-image:url("../img/603qm_herz_2.svg"); background-size: 50px 50px;}
    40%  {background-image:url("../img/603qm_herz_3.svg"); background-size: 50px 50px;}
    60%  {background-image:url("../img/603qm_herz_4.svg"); background-size: 50px 50px;}
    80%  {background-image:url("../img/603qm_herz_5.svg"); background-size: 50px 50px;}
    100% {background-image:url("../img/603qm_herz_1.svg"); background-size: 50px 50px;}
}

div {
    width: 50px;
    height: 50px;
    position: absolute;
    top: 50%;
    left: 50%;
    margin-top: -25px;
    margin-left: -25px;
    animation-name: loading-animation;
    animation-duration: 5s;
    animation-iteration-count: infinite;
    animation-timing-function: step-end;
}