Vertical height % does nothing?

I seem to be struggling with very basic things and I can’t find answers to my questions. Vertical height specified as a % appears to do nothing at all. The only way I found to make a div with no content be the size I want is by specifying pixel dimensions yet this is obviously not good for a responsive site.
Is there somewhere where I can find basic information about this kind of thing? I seem to be going round in circles trying all the settings yet most of them do absolutely nothing.

Hey @Mowgli

% are relative so you need to set the height of the parent element. In this case the body needs to be set to 100% befor any other height %s will work

Hope this helps

Alex

Thanks, that seemed to work but it opens up a series of problems when it comes to responsiveness. Is there no way of specifying relative vertical sizes?

What is the specific problem with reaposiveness?

If I have to specify a pixel height for a parent container, the container won’t grow taller to acommodate its content as it becomes narrower