The proposed css is targetted at use on a cellphone. The text is too large for a desktop and leaves the right half of a wide screen empty.
On a cellphone, the text is still slightly too large but is quite readable. It wraps at the screen edges but bounding boxes are off-screen on the right side.
Clearly, there is need for media queries to make good use of this css where it is most appropriate.
The Bulma CSS library uses the following break points for its media queries:
mobile: up to 768px
tablet: from 769px
desktop: from 1024px
widescreen: from 1216px
fullhd: from 1408px
and they seem to work well in my experience with cellphone, iPad, and 1920x1200 wide screen desktop.