Congressional left-proxy anchors
The same Left-LA demographic proxy (driven by the demographic weight boxes on the left) applied to whole congressional districts on a national all-CD z-basis, so recognizable safe-Dem urban seats anchor the LA CDs on one ruler. "natl %ile" = rank among all ~435 US CDs. Demographic proxy only (no campaign/turnout data) — fit on LA-City tracts, so applying it to other CDs is an illustrative extrapolation.