Yes, we know that, but unless you can produce a test example that we can examine, we can’t help you. The code you have posted so far doesn’t do that, so the problem is not with the code you have given.
As I suggested before, make up a test page of your own with the HTML and CSS you have posted. Test it on your desktop and then upload it to your site if you need to and test it, and see if the same thing happens.
It’s usually a good idea to set a font size on the body, I find, but I usually set it to 100%. It’s better not to use px, as that’s not as accessible. Anyhow, I’m not sure where you have put that 14px. I can’t see it.