Change css to make black
<p>I have fileupload control on my page and I have wrapped it around with fake button.Now I want to change the color of button to black.I tried various way but could not achieve. Here is my button and css:</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-css lang-css prettyprint-override"><code>.fileUpload {
  position: relative;
  overflow: hidden;
  margin: 10px;
}
.fileUpload input.upload {
  position: absolute;
  top: 0;
  right: 0;
  margin: 0;
  padding: 0;
  font-size: 20px;
  cursor: pointer;
  opacity: 0;
  filter: alpha(opacity=0);
}</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="col-xs-4"&gt;
  &lt;div class="fileUpload btn btn-primary"&gt;
    &lt;span&gt;Browse&lt;/span&gt;
    &lt;input type="file" name="File" id="fileUpload" class="upload" style="background-color: black" /&gt;
  &lt;/div&gt;
&lt;/div&gt;</code></pre>
</div>
</div>
</p>

<p>Please help.</p>