.container input {
    /* Hide default radio button */
    position: absolute;
    opacity: 1;
    cursor: pointer;
    height: 0;
    width: 0;
}

.checkmark {
    /*! Custom radio button */
    position: absolute;
    top: 1em;
    right: 1em;
    height: 1.5em;
    width: 1.5em;
    background-color: #eee;
    border: 1px solid silver;
    border-radius: 100%;
}

.check {
    border-radius: 5px;
}

.container:hover input~.checkmark {
    /*! On mouse-over, grau hinterlegt */
    background-color: #ccc;
}

.container input:checked~.checkmark {
    background-color: var(--dark-color);
    -webkit-box-shadow: 0px 0px 00px 0px #000000;
    box-shadow: 0px 0px 00px 0px #000000;
}

input:checked+.roundbutton {
    background-color: var(--dark-color);
}

.checkmark:after {
    content: "";
    position: absolute;
    display: none;
}


.container input:checked~.checkmark:after {
    display: block;
}


.container .checkmark:after {
    /*! kleiner kreis */
    top: 0.15em;
    left: 0.5em;
    transform: rotate(38deg);
    height: 0.8em;
    width: 0.3em;
    border-bottom: 0.2em solid white;
    border-right: 0.2em solid white;
}