On a phone under DX Life's header, the band ran 32px past the fold (y132 to y876 on an 844px
screen). The legend sheet's bottom and its collapsed strip began below the fold, so a reader who
collapsed the legend could not reopen it without scrolling. The band now takes the height that is
visible below its own top, capped at the old 88svh, which is also the fallback. It is measured once,
and again only on a width change, so the URL bar showing and hiding does not resize the map.
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