In order to center the horizontal menu, you have to edit the file template.css
Folder : templates > ja_purity_ii > css > template.css
We will modify the CSS class #ja-mainnav .main like this :
#ja-mainnav .main { font-size: 12px; margin: 0 auto; width: 980px; }
We suppose that in the template backend, the width is fixed with 980px (it works also with auto or specified in %).
