SubHeaderBar switched to ArcBackground variant="rect" (commit 207794e7)
when navigation was restyled with V-angled bars, but 15 pages still
rendered a 20px ARC_OVERHANG_PX spacer div directly below the tab bar
to leave room for the now-removed downward arc. That spacer is the
empty band the user reported underneath the tabs.
Drop the spacer divs and their now-unused ARC_OVERHANG_PX imports across
Feed, Search, Notifications, Profile, Videos, Photos, Relay, Letters,
Music, ExternalContent, ArticleEditor, PeopleListDetail, BadgeDetail,
Communities, and Badges. FollowPage keeps the import because it still
renders an actual <ArcBackground variant="down" /> at the top of its
profile feed scrollbox.
Chad Curtis
6eaef58db3