Some fonts are way too small to be used on the responsive design on Chrome for a regular Android phone.
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For some of those pages (the question list and question page), the reason that the text may look small is because you have the Desktop site setting turned off in chrome. See the following screenshot.
If you don't have Desktop site disabled, the pages won't be responsive. Keep in mind that other pages (like the profile page) are not responsive yet but I believe they will be soon.