Product page CSS Font-Size/layout

Good morning,

I am having no success in adjusting the look of my product page. The default product name font size is quite large and crashes into the price name. See attached screenshot.

In searching community support I found this post but that code has no effect whatsoever when I add it to the stylesheet.

I tried changing the basic h3 font size in the stylesheet, that did change the product name size but the crashing continues. See 2nd screenshot attachment. I have no idea how to resolve that.

I'm using Clean-Retina theme, I worry there's something about the theme that's causing this, because I'm not seeing it when I try other themes.