body {color: #FFFFFF; font-family: sans-serif, serif; text-align: center; background-color: #202020; animation: shiftcolor 5s ease infinite} @keyframes shiftcolor {0%{background-color: #202020;} 20%{background-color: #242424;} 40%{background-color: #282828} 60%{background-color: #282828;} 80%{background-color: #242424;} 100%{background-color: #202020;}}