Typo.
Also multiple line-height variable (e.g. $lines) with scale factor!
Add (but out-comment by default) sizes for mega, giga and tera headings within copy scope.
Update vertical spacing between main nav items; apply vertical rhythm (rem based!).
Add check for line height ($lines) in modular font system partial — if not `auto`, then multiply by scale factor.
Add (rem based) letter spacing to u-headingSettings; remove from alpha- and beta-sizes.