I have an  index.xhtml file, which is the landing page of my application.
I have a logout button which invokes the following method:
public String logout() {
    FacesContext.getCurrentInstance().getExternalContext().invalidateSession();
    return "logout";
}
Which in turns forwards to index.xhtml page from faces-config.xml. However, when I click on logout and reach the index.xhtml page, the page is distorted, without any css or any design.
Where am I getting wrong?