Is there a way in CSS to scale down/up all the content (text, buttons, images, padding, margins, etc) that is shown in the browser screen at once in a way similar to what zooming in/out the browser window itself would accomplish?

I am looking for a solution that is compatible with most modern browsers and does not require me to go over a legacy (and ill structured) large CSS style sheet changing fonts and other elements (e.g. padding, etc) by hand.

The solutions in Scale Up/Down all Elements, Images, Text when browser window width is changed do not work for me because either they use the non standard CSS zoom function or I need to reverse engineer the entire legacy CSS style sheet to do what the other answer there proposes.

Is there anything that could be done other than what is described in that question/answers more than 7 years ago? For example, is there a way I can tell (most modern) browsers programatically, e.g., zoom 80% ?

Thank you!