css3 buttons w/ color class

HTML

<a class="button default">my button</a>
<a class="button orange">my button</a>
<a class="button red">my button</a>
<a class="button blue">my button</a>
<a class="button green">my button</a>
<a class="button white">my button</a>

CSS

body { margin: 30px; background: #999; }
a {
    float:left;
    clear:both;
    margin: 10px;
}

a.button {
    cursor: pointer;
    color: white;
    text-shadow: 1px 1px 0px rgba(0,0,0,0.4);
    padding: 6px 20px;
    border-radius: 5px;
    box-shadow: inset 0px 1px rgba(255,255,255,0.3), 
        inset 0px -5px 20px rgba(0,0,0,0.4);
}

a.button:hover {
    box-shadow: inset 0px 1px rgba(255,255,255,0.3), 
        inset 0px -5px 20px rgba(0,0,0,0.4),
        0px 2px 6px rgba(0,0,0,0.4);
}

a.button:active {
    box-shadow: inset 0px 1px rgba(255,255,255,0.3), 
        inset 0px 5px 20px rgba(0,0,0,0.4);
}

a.button.default {
    background: #555;
    border:1px solid #333;
}

a.button.orange {
    background: #f50;
    border:1px solid #930;
}

a.button.red {
    background: #f00;
    border:1px solid #800;
}

a.button.blue {
    background: #0050FF;
    border:1px solid #003099;
}

a.button.green {
    background: #32CD32;
    border:1px solid #196719;
}

a.button.white {
    text-shadow: 1px 1px rgba(0,0,0,0.8);
    background: #efefef;
    border:1px solid #ddd;
}