How i can get the default font size from my theme?

Unfortunately, that specific editor toolbar button is for size so will put in inline CSS for font-size. There may be a CKEditor plugin for specifically H1/H2/H3, etc... However, you might be able to do like we did here and create your own custom button with a little HTML: 

 

  On 9/10/2021 at 4:18 PM, 403 - Forbiddeen said:

How i can get the default font size from my theme?

You can't replace it, but you can add an extra button for that in your editor. 

 

You can have both 🙂

  On 9/11/2021 at 9:54 AM, Jimi Wikman said:

You can have both 🙂

How you did it?

  On 9/14/2021 at 4:36 PM, 403 - Forbiddeen said:

How you did it?

You would add any items you wish to your toolbar. Take a look at the following guide for this. 

 

 

You may wish to add ckeditor plugins to facilitate this, which is what has been done above