* html, body{
    width: 100%;
    height: 100%;
}

.header {
    padding: 60px;
    text-align: center;
    background: #1abc9c;
    color: white;
    font-size: 30px;
}
.raam {
    border: 2px solid red;
    border-radius:15px;
}
.vierkant {
    height: 20%;
    width: 20%;
    background-color: green;
    border-radius:15px;
    font-size:40px;
    margin-left: 1;
    margin-right: 80;
    display:flex;
    align-items:center;
    text-align: center;
    font-family:sans-serif;
    padding: 25px ;
    display: inline-block;
    display: justify;
}