To improve your editing comfort on the platform, the text editor has been modified.
When you add text by clicking on the text icon or when you edit a question on a quiz or personality test, you now have this display :
You have a tab "Text in desktop" which gives you the preview of the text in desktop version.
If you only set this version, it will be the same on mobile.
But now you have a new tab "Text in mobile" which allows you to modify the preview in mobile.
In our case, we have a 40px font on desktop and 20px on mobile.
This modification is also active on quizzes, read the article on quiz settings
If you want to add a custom font you can read this article: How to customize a game with my font ?