#oldtime {
    animation: change 10s infinite;
    font-weight: 800;
}

@keyframes change {
    0% { color: #5cb85c; }
    25% { color: #556bd8; }
    50% { color: #e40707; }
    75% { color: #66e616; }
    100% { color: #67bd31; }
}