Update examples, add css

examples/window_focus.rs

@@ -1,3 +1,10 @@
+//! Listen for window focus events using a wry event handler
+//!
+//! This example shows how to use the use_wry_event_handler hook to listen for window focus events.
+//! We can intercept any Wry event, but in this case we're only interested in the WindowEvent::Focused event.
+//!
+//! This lets you do things like backgrounding tasks, pausing animations, or changing the UI when the window is focused or not.
+
 use dioxus::desktop::tao::event::Event as WryEvent;
 use dioxus::desktop::tao::event::WindowEvent;
 use dioxus::desktop::use_wry_event_handler;