Two fullscreen reliability fixes:
iOS Safari / HA Companion app (WKWebView): requestFullscreen() on custom elements either rejects silently or is missing entirely on iOS. A tap on the fullscreen button did nothing. A Promise-rejection / missing-API catch path now falls back to a CSS pseudo-fullscreen state with the same flex-chain layout, so the canvas fills the viewport just like the native path. Escape and a second tap exit.
Firefox desktop: the map kept rendering at its normal 540 px height in fullscreen, with the rest of the viewport black. Root cause was a CSS selector-list bug: :fullscreen, :-webkit-full-screen { ... } was discarded entirely because Firefox treats the webkit pseudo-class as invalid. Each pseudo-class now lives in its own rule, so the flex-chain layout takes effect in every browser.