Dear God, have we forgotten?
The WHOLE POINT of HTML - a LOGICAL page description language - is that you NEVER have to think or worry about the display device.
What happens if the display device is a text-reader for the blind?
Or a text-only browser on a console?
But that's not the main point; the main point is that HTML LOGICALLY describes the page. If you in your logical description of the page are making PURELY PHYSICAL descriptions then you GOT IT WRONG. You're writing web-pages like you're Word emitting HTML!
You need to write your web-site so it works LOGICALLY - which is to say, you leave the problem of rendering PURELY in the hands of the rendering agent. If you're not doing that, you've got it WRONG.