How to resize webpage content width on mobile to always fit screen at any zoom level?

I've seen this behavior on some webpages but I can't seem to find any information on how to recreate it. I would like my mobile webpage to be able to resize its content based on开发者_运维问答 the zoom level of the user's device (so that it always occupies 100% of the width).

Imagine a simple text paragraph; how can I make sure it always occupies 100% of the width of the phone as the user zooms in and out?

This is built-in to the mobile web browser. You do not need to do anything special. Test your site in the mobile web-browser and you will see it already has this functionality.