The biggest problem I have with html/css is that the outcome seems unpredictable; I sit with very experienced web devs and still have to do trial and error sometimes to know where what will be and of what size. I hear, way to often, when I (backend/embedded dev) ask how to ‘not make X happen’ something like ‘try this or this’ after they check my css. How is that software development if you have to guess how things work? Maybe it is because I am a backend dev, but we have this issue far less with native dev; they just say ‘do this’ and indeed it works as expected.