@keyframes clouds-loop-1 {
    to {
        background-position: -1000px 0;
    }
}

.clouds-1 {
    background-image: url("https://s.cdpn.io/15514/clouds_2.png");
    animation: clouds-loop-1 20s infinite linear;
}

@keyframes clouds-loop-2 {
    to {
        background-position: -1000px 0;
    }
}

.clouds-2 {
    background-image: url("https://s.cdpn.io/15514/clouds_1.png");
    animation: clouds-loop-2 15s infinite linear;
}

@keyframes clouds-loop-3 {
    to {
        background-position: -1579px 0;
    }
}

.clouds-3 {
    background-image: url("https://s.cdpn.io/15514/clouds_3.png");
    animation: clouds-loop-3 17s infinite linear;
}

.clouds {
    filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=40);
    opacity: 0.4;
    pointer-events: none;
    position: absolute;
    overflow: hidden;
    top: 0;
    left: 0;
    right: 0;
    height: 100%;
}

.clouds-1,
.clouds-2,
.clouds-3 {
    background-repeat: repeat-x;
    position: absolute;
    top: 0;
    right: 0;
    left: 0;
    height: 500px;
}