What can I do to make my site mobile optimized?

Question

css

Hello! I have a site on Wordpress. I am using a responsive theme. Edited it with my CSS. Now Google tells me that the site is not adapted for mobile. Although, initially - was.
I can’t understand where exactly the errors are and what to do (at least approximately in what part) to fix it. Please help me figure it out. Thanks in advance!
Website - https://kinvestor.ru

Answer 1

Yes, and what exactly broke I do not understand. Already tested on different mobile devices.

1. Download WinMerge
2. Install the subject from item 1
3. Give the subject from item 2 two files - the source and the current one
4. Put on the glasses.
5. Look at the screen.