Unable to change font size

I’m using the free version (still deciding whether or not to upgrade) and unable to change the font sizes for the Title and info. I’m using the snippets for CSS styling here: https://wpdrawattention.com/guides/styling-with-css/#change-title-styling to set a border around the photo, and change font sizes. I can see the changes on mobile device, but not when viewing on desktop (Mac on Firefox and Chrome), regardless of how often I clear cache and browser. How can I get the changes to show up on desktop version of the website?