Tip: when you have a header text with subtext underneath or above, it’s usually effective to divide the font-size by 2 (50px/25px). And when you have a title, subtext and a button, it’s also usually effective to try to keep the same space between the three items.
Tip2: italics add another level of complexity. It shouldn’t be used as a refinement. Here you’re using a serif font as a refinement, which is way enough to make it stand out.