/***************************
 RGBA Background Colours
***************************/

.rgba(@r, @g, @b, @alpha) {
    @colour: rgb(@r, @g, @b);
    @alphaColour: hsla(hue(@colour), saturation(@colour), lightness(@colour), @alpha);
    @alphaColour: rgba(@r, @g, @b, @alpha);
    @ieAlphaColour: argb(@alphaColour);
    
    background-color: @colour; // Fallback for older browsers
    // This will be ignored by browsers that don't support it.
    background-color: @alphaColour;
    
    // OldIE hacks
    .lt-ie9 & { //assumes you have conditional commented <html> tags
        zoom: 1; // hasLayout
        background-color: transparent;
        -ms-filter:  "progid:DXImageTransform.Microsoft.gradient([email protected]{ieAlphaColour}, [email protected]{ieAlphaColour})"; // IE 8+
        filter: ~"progid:DXImageTransform.Microsoft.gradient([email protected]{ieAlphaColour}, [email protected]{ieAlphaColour})"; // IE 6 & 7
    }
    
}