Stylus mixin for Rem Font Sizing

font-size(_size)
    if typeof(_size) == 'unit'
        if unit(_size) == 'rem'
            font-size (_size*10)px
    font-size _size

//Usage
p
    font-size 1.2rem

yields

p{
    font-size: 12px;
    font-size: 1.2rem;
}

Update: Fixed font-size: normal. Thanks icylace