CSSLayout and display attribute

Hi. I’ve tried to create float layout using CSSLayout:

public class FloatLayout extends CssLayout {

	private static final long serialVersionUID = -1844586541069804368L;
	
	public FloatLayout() {
		setSizeFull();
	}

	@Override
	protected String getCss(Component c) {
		return "display: inline-block; background: green;";
	}
	
}

Then i add components to it like this:

FloatLayout lay = new FloatLayout();
for(int i = 0; i < 100; i++) {
	lay.addComponent(new Label("Label " + i));
}

and in resulting HTML it gave me this:

<div class="v-label" style="background-attachment: scroll; background-repeat: repeat; background-image: none; background-position: 0% 0%; background-size: auto; background-origin: padding-box; background-clip: border-box; background-color: green; width: 783px;">Label 1</div>ev
<div class="v-label" style="background-attachment: scroll; background-repeat: repeat; background-image: none; background-position: 0% 0%; background-size: auto; background-origin: padding-box; background-clip: border-box; background-color: green; width: 783px;">Label 2</div>
...

As you can see, color attribute set, display - not. What am I doing wrong?