body {
    margin: 0;
    height: 100vh;
    background-color: lightgrey;
    display: flex;
    align-items: center;
    justify-content: center;
}

.yin-yang {
    width: 10em;
    height: 10em;
    font-size: 20px;
    --color1: white;
    --color2: black;
    background-image: linear-gradient(var(--color1) 50%, var(--color2) 50%);
    display: flex;
    align-items: center;
    box-shadow: 0 0 1em rgba(0, 0, 0, 0.3);
    animation: rotating linear 5s infinite;
}

@keyframes rotating {
    to {
        transform: rotate(1turn);
    }
}

.yin-yang::before,
.yin-yang::after {
    content: '';
    width: 50%;
    height: 50%;
    background-color: var(--inner-color);
    box-sizing: border-box;
    border: 1.5em solid var(--outer-color);
}

.yin-yang::before {
    --inner-color: var(--color1);
    --outer-color: var(--color2);
}

.yin-yang::after {
    --inner-color: var(--color2);
    --outer-color: var(--color1);
}

.yin-yang,
.yin-yang::before,
.yin-yang::after {
    border-radius: 50%;
}