body {
    animation: theme 21s linear infinite;

    /*test*/

    &:after,
    &:before {
        content: '';
        display: block;
        position: fixed;
        z-index: -1;
        top: 0;
        width: 100vw;  // IE/Edge
    height: 100vh; // fallback
    width: 100vmax;
        height: 100vmax;
        background: rgba(0,0,0,0.035);
        animation: background 90s linear infinite;
    }

    &:after {
        left: 15vw;
    }

    &:before {
        right: 15vw;
        animation-delay: -30s;
        animation-direction: reverse;
    }
}

@keyframes theme {
    0% {
        background: rgb(255, 255, 255, 0.3);
    }

    16% {
        background: rgb(255, 255, 255, 0.5);
    }

    33% {
        background: rgb(255, 255, 255, 0.7);
    }

    50% {
        background: rgb(255, 255, 255, 0.9);
    }

    66% {
        background: rgb(255, 255, 255, 0.7);
    }

    83% {
        background: rgb(255, 255, 255, 0.5);
    }

    100% {
        background: rgb(255, 255, 255, 0.3);
    }
}

/*@keyframes theme {*/
/*    0% {*/
/*        background: rgb(126, 217, 253, 0.15);*/
/*    }*/

/*    16% {*/
/*        background: rgb(126, 217, 253, 0.3);*/
/*    }*/

/*    33% {*/
/*        background: rgb(126, 217, 253, 0.45);*/
/*    }*/

/*    50% {*/
/*        background: rgb(126, 217, 253, 0.5);*/
/*    }*/

/*    66% {*/
/*        background: rgb(126, 217, 253, 0.4);*/
/*    }*/

/*    83% {*/
/*        background: rgb(126, 217, 253, 0.25);*/
/*    }*/

/*    100% {*/
/*        background: rgb(126, 217, 253, 0.15);*/
/*    }*/
/*}*/

@keyframes background {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}