.loader {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    border: 20px solid purple;
    border-top: 20px solid cyan;
    animation: ani 2s ease-in 0s infinite normal;
}

@keyframes ani {
    from {
        transform: rotate(0deg);
    }

    to {
        transform: rotate(360deg);
    }
}