I have this idea for new relative CSS units; they are similar to 'vh' and 'vw' units but instead of being relative to the dimensions of the viewport, they would be relative to the dimensions of the parent element. Therefore it could be easier to create 'divs' with specific aspect ratios, and probably make life easier for CSS purists.
Anyway I would really appreciate some help to make this idea come true and this could also come in handy for others who also have feature ideas.