title: bootstrap collapse bar turns transparent when window is reduced
body: <p>im having issues with my bootstrap responsive background.</p>
  
  <p>as seen below, when my window is reduced to simulate a mobile screen size, my dropdown becomes transparent.</p>
  
  <p><a href="https://i.stack.imgur.com/sxvvr.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sxvvr.png" alt="navbar"></a>
  </p>
  
  <p>this is my code, which was copied from the bootstrap sample websites, the only change i made was the links.</p>
  
  <pre><code>&lt;div class="navbar navbar-inverse navbar-fixed-top"&gt;
        &lt;div class="container"&gt;
          &lt;div class="navbar-header"&gt;
            &lt;button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse"&gt;
              &lt;span class="icon-bar"&gt;&lt;/span&gt;
              &lt;span class="icon-bar"&gt;&lt;/span&gt;
              &lt;span class="icon-bar"&gt;&lt;/span&gt;
            &lt;/button&gt;
            &lt;a class="navbar-brand" href="#"&gt;Project name&lt;/a&gt;
          &lt;/div&gt;
          &lt;div class="navbar-collapse collapse"&gt;
            &lt;ul class="nav navbar-nav"&gt;
              &lt;li class="active"&gt;&lt;a href="#"&gt;Dashboard&lt;/a&gt;&lt;/li&gt;
              &lt;li&gt;&lt;a href="#pages"&gt;Pages&lt;/a&gt;&lt;/li&gt;
              &lt;li&gt;&lt;a href="#extensions"&gt;Extensions&lt;/a&gt;&lt;/li&gt;
              &lt;li class="dropdown"&gt;
                &lt;a href="#" class="dropdown-toggle" data-toggle="dropdown"&gt;Dropdown &lt;b class="caret"&gt;&lt;/b&gt;&lt;/a&gt;
                &lt;ul class="dropdown-menu"&gt;
                  &lt;li&gt;&lt;a href="#"&gt;Action&lt;/a&gt;&lt;/li&gt;
                  &lt;li&gt;&lt;a href="#"&gt;Another action&lt;/a&gt;&lt;/li&gt;
                  &lt;li&gt;&lt;a href="#"&gt;Something else here&lt;/a&gt;&lt;/li&gt;
                  &lt;li class="divider"&gt;&lt;/li&gt;
                  &lt;li class="dropdown-header"&gt;Nav header&lt;/li&gt;
                  &lt;li&gt;&lt;a href="#"&gt;Separated link&lt;/a&gt;&lt;/li&gt;
                  &lt;li&gt;&lt;a href="#"&gt;One more separated link&lt;/a&gt;&lt;/li&gt;
                &lt;/ul&gt;
              &lt;/li&gt;
            &lt;/ul&gt;
            &lt;div class="navbar-right"&gt;
              &lt;p style="color:#fff;"&gt;some text&lt;/p&gt;
            &lt;/div&gt;
          &lt;/div&gt;&lt;!--/.navbar-collapse --&gt;
        &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>[EDIT]
  i have this in my header</p>
  
  <pre><code>&lt;meta charset="utf-8"&gt;
       &lt;meta name="viewport" content="width=device-width, initial-scale=1.0"&gt;
       &lt;meta name="description" content=""&gt;
       &lt;meta name="author" content=""&gt;
  </code></pre>