title: Can't apply css styles to Administrate gem UI views to make responsive
body: <p>I'm trying out the Administrate gem in a Rails 4 app. It seems to work well and I like the clean UI. However, I need a responsive UI to allow the admin operations on mobile devices. I've looked everywhere in my project for possible css files which I could possibly modify but can't find anything related to the Administrate views. </p>
  
  <p>Searching in browser developer tools reveals this css file path:
  I can see a link to a stylesheet in the html head section pointing to this path:</p>
  
  <pre><code>/assets/administrate/application.self-c72e7c1a6aca7d4e9ae8ec6fdd92a87e81881a0012158db0cf618e4f2012d26f.css?body=1
  </code></pre>
  
  <p>I am not exactly sure what is going on here. The administrate folder does not appear to exist anywhere in the project. I checked <code>app/assets</code> and <code>lib/assets</code>. I thought the css styles might be being applied inline when the page is rendered but again didn't find anything in the UI's elements apart from classes<code>(eg. class="sidebar")</code>. The <a href="https://github.com/thoughtbot/administrate" rel="nofollow">Administrate documentation</a> doesn't contain anything about customizing the interface either. It does say the gem's source code lives in the <code>app</code> and <code>lib</code> directories, but as I mentioned I can't find anything in either.</p>
  
  <p>Maybe the css is being compiled by some hidden pre-processing on the fly? 
  I understand that messing with the UI might not be recommended and could break the UI unexpectedly. All the same I'd like to give it a try.If anyone has had any luck customizing it for responsiveness I'd be grateful for any pointers to get started. Maybe there is something I am missing that can be tweaked in the Administrate settings. Thanks! </p>