Code for multiple txt styles in one block?

Hi

I'm trying to create a headline & sub-headline of different sizes much closer vertically than the standard padding that adding two text blocks generates.

I assumed I needed to do this with a markdown block. I tried it and it works but it causes errors on my page, namely it cause some other blocks to disappear outside of the editor. Here's the code I used:

<span style="font-size: 20px;">Product title(1p)</span><br>
<span style="text-transform: uppercase; letter-spacing: 0.09em; font-size: 15px;">$price</span>

Anyone have a better markdown code block for this common issue? Or is there another way I should be looking to address it?

If you can see it, it's at: https://apricots-fuchsia-m3r5.squarespace.com/gear

Thanks!