How to add a flat button to Twitter Bootstrap v2.x

Bootstrap flat button

.btn-flat {
    filter:progid:DXImageTransform.Microsoft.Gradient(enabled='false');
    -webkit-box-shadow: none;
    -moz-box-shadow: none;
    box-shadow: none;
    background-image:none;
    border:0;
}

I added it AFTER the following IE hack lines:

.btn-inverse:active,
.btn-inverse.active {
background-color: #080808 \9;
}