Font Magra seems to be working in my Chrome browser on your site. Was there a specific font that wasn’t working?
With regards sidebars. Sidebar 1 is the outer sidebar which as the screen gets smaller repositions under sidebar 2 (inner). So for some sizes they will be wider. Sidebar 3 provides full sidebar width at the top at all sizes.
You currently only have widgets in sidebar1, the outer sidebar. So at full desktop the gap is for sidebar 2. Try moving theme to sb3 or adding some widgets to sb2.
The setup provides a great deal of flexibility, but you have to make a choice as to which sidebars and combinations of widgets works for you.
Also facebook widgets are not responsive, so they will not scale properly in a responsive theme.