Updated Styling intro to mention Aura loaded by default if no AppShellConfigurator is defined. (#5405)

Co-authored-by: Petter Holmström <petter@vaadin.com>

Author: 2 people

articles/styling/index.adoc

@@ -46,7 +46,11 @@ The Vaadin 24 way of loading styles through the [annotationname]`@Theme` annotat
 
 == Themes
 
-By default, Vaadin components are rendered with their minimalistic built-in <<themes/base#, base styles>>, which are a good starting point if you want to customize the look and feel extensively. Vaadin also ships with two themes, <<themes/aura#, Aura>> and <<themes/lumo#, Lumo>>, that provide a more polished look and feel for Vaadin components.
+Vaadin components come bundled only with minimalistic, built-in base styles, on top of which the application can load one of the two Vaadin themes, <<themes/aura#, Aura>> or <<themes/lumo#, Lumo>>, which provide a more polished look and feel.
+
+If no [interfacename]`AppShellConfigurator` is defined for the application, the Aura theme will be loaded automatically. Otherwise either theme needs to be loaded explicitly using the [annotationname]`@StyleSheet` annotation.
+
+While both themes are highly customizable, you can also choose to implement your own custom styling directly on top of the <<themes/base#, base styles>> in order to avoid having to override the styling provided by the theme.
 
 [cols="^.^1, ^.^1, ^.^1"]
 |===