[<lvi, svi, etc> are] equal to 1% of the size of the large viewport size, small viewport size, and dynamic viewport size (respectively) in the direction of the root element’s inline axis.

If writing-mode is propagated from body to the viewport, are these units supposed to resolve according to the propagated writing-mode (e.g. if used on e.g. the root element)? At the time we know what to propagate from body, it's too late to change any interpretation of *i,*b on root.

Can we specify that these units resolve against the computed value of writing-mode on the root element? This is what WebKit did in their implementation.