*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
.box{
    color: black;
    font-size: 3rem;
    font-weight: 700;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #00ff00;
    height: 400px;
    width: 400px;
}
h1:hover{
    text-decoration: underline wavy pink 4px;
}