Panel in center of Web-page

Hello all, i`m hust trying to make panel component display in the center of web page, but panel displayed in the left top corner of window. How can i decide it? Thanks a lot GridLayout gl = new GridLayout(); Panel aPanel = new Panel("Hello world"); HorizontalLayout hl = new HorizontalLayout(); aPanel.setContent(hl); hl.addComponents(new TextField("Login"), new TextField("Password"), new Button("Register")); gl.addComponent(aPanel); gl.setComponentAlignment(aPanel, Alignment.MIDDLE_CENTER); setContent(gl)

Something like this does the trick:

VerticalLayout root = new VerticalLayout():
root.setComponentAlignment(yourPanel, Alignment.MIDDLE_CENTER);