I wasn't aware of "ch". Why prefer it to rem? (and isn't ch in family with em, not rem - that is, "advance width" relative to element font size, not root element font size?)
Ed: i guess in this case 1 rem is roughly 2 em (styled element has 50% font size) - and 1 ch is roughly 1 em?
Ed: i guess in this case 1 rem is roughly 2 em (styled element has 50% font size) - and 1 ch is roughly 1 em?