title: Top navbar overlaps with main content
body: <p>I'm converting my landing page from Bootstrap to Semantic-UI. The page has a position fixed top navbar. The main content is divided in two columns (3-cols and 9-cols). The left column is used to show a sidebar and the right column is used for current content.</p>
  
  <p>I tried to copy and paste the demo page of Semantic-UI. The navbar is 45px high. I noticed that the first 45px of main content is overlapped.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;link href="//semantic-ui.com/dist/semantic.min.css" rel="stylesheet"/&gt;
  &lt;script src="//semantic-ui.com/dist/semantic.min.js"&gt;&lt;/script&gt;
  
  &lt;div id="navbar" class="ui fixed inverted main menu"&gt;
    &lt;div class="container"&gt;
      &lt;div class="title item"&gt;
        &lt;b&gt;Dashboard&lt;/b&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;
  
  &lt;div id="maincontent" class="ui bottom attached segment pushable"&gt;
      
    &lt;div id="sidebar" class="ui visible left vertical sidebar menu"&gt;
      &lt;a class="item"&gt;First Item&lt;/a&gt;
      &lt;a class="item"&gt;Second Item&lt;/a&gt;
      &lt;a class="item"&gt;Third Item&lt;/a&gt;
      &lt;a class="item"&gt;Fourth Item&lt;/a&gt;
      &lt;a class="item"&gt;Fifth Item&lt;/a&gt;
    &lt;/div&gt;
      
    &lt;div id="content" class="pusher"&gt;
      &lt;div class="ui basic segment"&gt;
        &lt;h3 class="ui header"&gt;Application Content&lt;/h3&gt;
        &lt;p&gt;First paragraph...&lt;/p&gt;
        &lt;p&gt;Second paragraph...&lt;/p&gt;
        &lt;p&gt;Third paragraph...&lt;/p&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>My current workaround is to add a 45px high placeholder after navbar.</p>
  
  <pre><code>&lt;div style="height:45px"&gt;&lt;/div&gt;
  </code></pre>
  
  <p>I'm pretty sure there are some good css style names can fix the content overlapping. </p>