how to add negative radius in css code example

Example: negative border radius

.player {
    width: 480px;
    height: 80px;
    border-radius:0 40px 40px 0;
    background-color:#0000FF;
    position:relative;    
    color:#FFF;
}

.player:before
{
    width: 80px;
    height: 80px;
    border-radius:0 40px 40px 0;
    background-color:#FFF;    
    display:inline-block;
    vertical-align: middle;
    margin-right: 10px;
    content: '';
}