Delegates to the canonical UI theme engine (_UITheme.applyTheme) when it is
loaded, so that localStorage persistence, the #geoleaf-map container class
(fullscreen support), the toggle button's aria-pressed state and the
geoleaf:ui-theme-changed event all stay in sync. Falls back to a plain body
class swap when GeoLeaf.UI is absent.
Sets and applies the active theme.
Delegates to the canonical UI theme engine (
_UITheme.applyTheme) when it is loaded, so that localStorage persistence, the#geoleaf-mapcontainer class (fullscreen support), the toggle button'saria-pressedstate and thegeoleaf:ui-theme-changedevent all stay in sync. Falls back to a plain body class swap whenGeoLeaf.UIis absent.