Thank you. I am not a coder, but I will try to make them myself then.

I know how to inspect elements and read the classes.
But in this thread Calin recommended me to create a class and assign it to element (without necessity to dig its name with the browser’s inspector). Therefore my question was totally different.
I asked whether you have ready-to-use classes for hiding/displaying elements on various screen sizes. Then I cann assign such classes to particular elements to show/hide them. For example, xx-hide-on-mobile, xx-show-on-mobile, xx-hide-on-desktop etc
I used another theme in the past and they made such classes available for the users. It was very convenient in some situations.

Thanks for your suggestion. Are there any standard classes to hide/display an element for mobile/tablet/phone etc, or do I have to develop and insert my own CSS classes into the Theme Panel/Custom code?

I had the same issue with the galleries.
But in my case the images on laptop screen were ok. But they were blurry on my desktop monitor which has resolution of 2560×1440. The inspector says my thumbnail is 300×450 pixels, but in fact physically they had (at least) twice more pixels.
Finally, I have installed another gallery with Retina support. This gallery generates photo thumbnails for bigger screens too. And the issue have göne.

So, I think that either you can try to seek for some Retina plugin for WP, or the theme developers must add support of Retina screens.

• This reply was modified 3 years by Sergey.