Bradley's Equalizer Landing Page built with Vue, Sass

This is my first project building from mobile first. In general, I tend to use 'rem' measures for sizing and sometimes spacing elements to keep layouts consistent. However, for typography, I used the exact px measures for font size, spacing, line height, etc. Is this a good approach? Any drawbacks?

I tried to scale the design for as many possible device layouts as I could, which meant adapting the design beyond mobile, table, desktop designs provided. I added responsiveness for narrow fold-able phones and hires desktops. Are there other devices that I should keep in mind when building?

I found layering the body elements very challenging since they were all askew from each other and had different layouts based on mobile vs not-mobile. It's odd that this project is labeled as beginner; or maybe, I still have a lot to learn about CSS!