You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: viewport_debug.rs
    path of file: ./repos/bevy/examples/ui
    
    the code of the file until where you have to start completion: //! A simple example for debugging viewport coordinates
//!
//! This example creates two uinode trees, one using viewport coordinates and one using pixel coordinates,
//! and then switches between them once per second using the `Display` style property.
//! If there are no problems both layouts should be identical, except for the color of the margin changi
    
fn main() {
    App::new()
        .insert_resource(UiScale(2.0))
        .add_plugins(DefaultPlugins.set(WindowPlugin {
            primary_window: Some(Window {
                title: "Viewport Coordinates Debug".to_string(),
                // This example relies on these specific viewport dimensions, so let's explicitly
                // define them.
                resolution: [1280., 720.].into(),
                resizable: false,
                ..Default::default()
            }),
            ..Default::default()
        }))
        .add_systems(Startup, setup)
        .add_systems(Update, update)
        .run();
}