test-stylesheet.css

.colormination {
    animation-name: color_change;
    animation-duration: 3s;
    animation-iteration-count: infinite;
    animation-direction: alternate;
}

@keyframes color_change {
    0% { color: blue; }
    25% { color: orange; }
    50% { color: yellow; }
    75% { color: black; }
    100% { color: red; }
}