By default the Total theme centers all your content based on your site widths settings or default values. If you want you can make your entire site 100% wide by tweaking these settings, however, you can also have centered content with a full-width header if wanted via the option available at Appearance > Customize > Header > General. Simply check the “Full-Width” box and it will extend your header to the full-screen size. This is particular useful for Header Style One, which will make your logo go all the way to the left and your menu all the way to the right (with a little padding of course). For other header styles…not so useful.