Untitled

body { 
	background: linear-gradient(35deg, #000000, #00ff76, #000000);
    background-size: 600% 600%;

    animation: AnimationName 21s ease infinite;
}

@keyframes AnimationName {
    0%{background-position:91% 0%}
    50%{background-position:10% 100%}
    100%{background-position:91% 0%}
}