is it possible to have more than one text style in a text holder?

I want to set up a text holder that shows that your header should be bold, and the body copy should be light (for example). When I set up a text holder it initially appears with placeholder text in 'levels' which suggests it is possible, but when I edit these levels this does not appear in the actual slide, it just shows one text style (whichever is at the top of the text holder). Where am I going wrong? Or is this just not possible? thank you!

Here is my CustomLayout. I have edited the text-holder by selecting the particular lines and changing its formatting to look something like this:

In my normal slides, I can type within the placeholder. To trigger the formatting of Level 2 and the others, I'll have to indent the line by pressing TAB on my keyboard. My final result looks something like this: