body {
    margin: 0;
    height: 100vh;
    background: linear-gradient(cyan, purple);
    display: flex;
    justify-content: center;
    align-items: center;
}
.circle {
    background-color: yellow;
    height: 200px;
    width: 200px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 4rem;
    border-radius: 50%;
}