De CSS is hier niet zo handig georganiseerd: minder functioneel opgebouwd en onhandige herhaling

nietZoHandig.css

.button-koop {
    width: 9em;
    height: 2.45em;
    background-color: darkcyan;
    font-family: Arial, Helvetica, sans-serif;
    text-decoration: none;
    text-align: center;
    line-height: 2.45em;
    display: inline-block;
    color: #fff;
    font-weight: 900;
    font-size: .8em;
    margin: 0 .5em;
    border-radius: .2em;
}
.button-koop:hover {
    background-color: forestgreen;
}
.button-annuleer {
    width: 9em;
    height: 2.45em;
    background-color: rgb(96, 96, 96);
    font-family: Arial, Helvetica, sans-serif;
    text-decoration: none;
    text-align: center;
    line-height: 2.45em;
    display: inline-block;
    color: #fff;
    font-weight: 900;
    font-size: .8em;
    margin: 0 .5em;
    border-radius: .2em;
}
.button-annuleer:hover {
    background-color: rgb(34, 34, 34);
}