.rounded-corners (@radius: 5px) {
    -webkit-border-radius: @radius;
    -moz-border-radius: @radius;
    border-radius: @radius;
}
.rounded-corners (@top-left, @top-right, @bottom-right: 0, @bottom-left: 0) {
    -webkit-border-radius: @arguments;
    -moz-border-radius: @arguments;
    border-radius: @arguments;
}
.shadow (@x, @y, @blur, @spread, @color) {
    -webkit-box-shadow: @arguments;
    -moz-box-shadow: @arguments;
    box-shadow: @arguments;
}
/* apply a natural box layout model to elements */
.border-sizing(@model) {
    -webkit-box-sizing: @model;
    -moz-box-sizing: @model;
    box-sizing: @model;
}
/*http://developer.yahoo.com/blogs/ydn/posts/2012/10/clip-your-hidden-content-for-better-accessibility/*/
.accessibly-hidden() {
    position: absolute;
    clip: rect(1px 1px 1px 1px); /* IE6, IE7 */
    clip: rect(1px, 1px, 1px, 1px);
    padding:0;
    border:0;
    height: 1px;
    width: 1px;
    overflow: hidden;
}
