Messages appear at the top centre below the header as an inverted chip
of the theme, in the app's font and without icons, and close on a click
instead of sliding in at the bottom right in Notyf's red.
Ceviz, Gece and Yeşim themes as CSS variables on <html>, Bricolage
Grotesque, shared styles, and one header for every page with theme
swatches, the account menu and the page's main action. The lobby,
privacy page and status panels use the new look.
