title: Change theme of my github pages, and pages are empty
body: <p>I'm new to <code>Github pages</code> and <code>Jekyll</code>, I follow the steps about how to build Github pages, and then succeed. When I changing the theme in <code>Settings</code> and refresh, it shows nothing in main page.</p>
  
  <p>I don't override <code>_layouts</code> or anything else. Because it says Github support the theme so I would think I should do nothing to support the new theme, just like the default theme <code>Minima</code>.</p>
  
  <p>So I wonder, does it just go like this or I missing something? Thanks for any idea :)</p>