* {
    margin: 0;
    padding: 0%;
    box-sizing: border-box;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    max-width: 100vw;
    min-height: 100vh;
}

div {
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: teal;
    text-align: center;
    width: 100px;
    height: 100px;
    border-radius: 50%;
    font-size: 30px;
    transition: width 0.3s, height 0.3s , border-radius 0.3s;
    cursor: pointer;
}