title: Pushed content with Semantic UI visible sidebar is too wide
body: <p>When using a visible Semantic UI sidebar the content in pusher is too wide. It has the width of the browser window, not the width of the available space.</p>
  
  <pre><code>&lt;div class="pushable"&gt;
      &lt;div class="ui left vertical inverted visible sidebar menu"&gt;
          &lt;a class="item" href="/"&gt;Item&lt;/a&gt;
      &lt;/div&gt; 
      &lt;div class="pusher"&gt;                                                                                 
              My content 
          &lt;table class="ui red table"&gt;&lt;thead&gt;&lt;th&gt;1&lt;/th&gt;&lt;/thead&gt;
              &lt;tbody&gt;&lt;td&gt;Test&lt;/td&gt;&lt;/tbody&gt;
          &lt;/table&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>See a jsfiddle here:
  <a href="http://jsfiddle.net/xh9p6tgb/1/" rel="noreferrer">http://jsfiddle.net/xh9p6tgb/1/</a></p>