SOURCE

<div>
    <span></span>
    <span></span>
</div>

body{
    height: 90vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

div{
    width: 300px;
    height:300px;
    border-radius: 50%;
    background: linear-gradient(to right, #000 50%, #fff 50%);
    position: relative;
    box-shadow: 0 0 8px #ccc;
    transform: rotate(0deg);
    animation: rotate linear 2.5s infinite;
}

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

    100%{
        transform: rotate(1turn);
    }
}

div::before,
div::after{
    content: '';
    width: 150px;
    height: 150px;
    border-radius: 50%;
    position: absolute;
}

div::before{
    left: 75px;
    top: 0;
    background: #000;
}

div::after{
    bottom: 0;
    left: 75px;
    background: #fff;
}

div > span{
    width: 50px;
    height: 50px;
    border-radius: 50%;
    position: absolute;
}

div>span:nth-child(1){
    top: 50px;
    left: 125px;
    background: #fff;
}

div>span:nth-child(2){
    bottom: 50px;
    left: 125px;
    background: #000;
    z-index: 1;
}