Spec - applying styles to spec presenters (both Morphic and GTK3)

SpecApplyingStylesToSpecPresentersBEtc.st

app := SpApplication new.

"If using Morphic"
app addStyleSheetFromString: '.application [
	.red [ Draw { #color: #red } ],
	.green [ Draw { #color: #green } ]	
]'.

"If using GTK (you need to choose one, both options are not possible at the same time)"
app useBackend: #Gtk.
app addCSSProviderFromString: '
.red { background-color: red }
.green { background-color: green }	
'.
 
presenter := SpPresenter new.
presenter application: app.

presenter layout: (SpBoxLayout newTopToBottom
	add: (textPresenter := presenter newTextInput) expand: false;
	addLast: (SpBoxLayout newLeftToRight 
			add: (presenter newButton
				label: 'Red';
				action: [ textPresenter removeStyle: 'green'; addStyle: 'red' ];
				yourself);
			add: (presenter newButton
				label: 'Green';
				action: [ textPresenter removeStyle: 'red'; addStyle: 'green' ];
				yourself);
			yourself)
		expand: false;
	yourself).
	
presenter asWindow 
	title: 'Example applying styles';
	open

and this is the result :