How do you handle custom controls and styling in .NET MAUI?

Create fully custom controls by defining a cross-platform class deriving from View, adding bindable properties, and implementing platform-specific handlers with ViewHandler<TView, TPlatformView>.
Handlers override CreatePlatformView(), ConnectHandler(), and DisconnectHandler() to manage native views (e.g., EditText on Android), plus property/command mappers for syncing properties.
Register in MauiProgram.cs with builder.ConfigureMauiHandlers(handlers => handlers.AddHandler<Video, VideoHandler>());