Having made a sticky footer, I have been trying to get the content columns to be full height. The test file is at https://www.thebusinessmechanic.com/test/framework.html
The container coloured light grey is full height but I can't find how to make the two equal height columns fill the space to the footer so that their height is not limited by the content.
Having spent a lot of time confusing myself with the flexbox specification, I confess myself beaten. Does anybody have a solution?