Fullsize Browser Breaks Design: Fonts Shrink, White Spaces Increase

I designed a page without considering full-size browsing because I personally never maximize my browser.

However, I didn't realize that maximizing the browser would have such a dramatic impact on the output. The website looks fine when the browser isn't maximized, even if it's quite large. But as soon as it's maximized, the fonts shrink and white spaces increase, effectively breaking the design.

I'm wondering if there's any custom CSS code that can prevent this from happening. 

This worked, thank you!