It can be tricky, while integrating the figma design file,
to map some small px values to their rem equivalent. Thus,
this PR proposes a new util function converting pixel to rem.
It would ensure that all size values can scale base on the
font-size base, while keeping a good developer experience.
Based on recent feedbacks this feature was needed. It is important for
the label to still be accessible to screen readers, that's why we
introduced the offscreen class.
Resolve#60
