QR Code with CSS Grid and Flexbox

This solution creates a scroll bar when I include the attribution line in the footer. I'm not exactly sure what to do to get this page to render without a scrollbar.

I'd also like feedback on how the CSS is set up. I built this out haphazardly, so I am fairly certain that this isn't the right way to organize a CSS file. For example:

• I feel that the headline and subtitle classes can be consolidated down somehow, I the only differences between these two classes are the font weights, so there are a lot of duplicated lines
• I'm uncertain if how I nested the classes under the widget class is the proper way to organize the CSS. It works, but I, personally, think it's difficult to follow the relationships when looking at the code.