sass simple mixin

mixin1.css

@mixin floaty($minimized-by-default, $side: left){
    float: $side;
    width: 300px;
    @if $minimized-by-default {
        overflow: hidden;
        width: 5px;
    }
}

.navigation{
    background: green;
    @include floaty(false);
}
.navigation.secondary{
    background: blue;
    @include floaty(true, right);
}