I’m aiming for viewport unit based typography and was seing html “root” setup as a reference in any source I could find. So far we are using Typography > Body, but our end goal is
html { font-size: calc(1em + 1vw) }
And not sure I can use calculation with typography > body
html is for the root font size which will overide that defined by the browser which is 16px which eauals 1 REM. So if you wanted to use REM sizes in your builds then html is the one to adjust.
body only affects the paragraph text. H1, H2 etc are all separate tags and need to be styled separately. What are you trying to achieve? Golden Ratio modular scale? Fluid typography?
Fluid is good if you are working with full width sections and more ‘complex’ designs where elements are likely to be rescaled but for standard site layouts media queries are the easier to manage.