title: How to change format of Warning admonition or add Caution in Sphinx HTML output
body: <p>This seems like it should be straightforward but I've been prowling the documentation and web and haven't found the answer. </p>
  
  <p>I want to output HTML doc from Sphinx. Ideally I'd like to have three levels of "note" type highlighted text boxes. ReST defines several "admonitions": (<a href="http://docutils.sourceforge.net/docs/ref/rst/directives.html#admonitions" rel="nofollow">http://docutils.sourceforge.net/docs/ref/rst/directives.html#admonitions</a>) but most of the Sphinx HTML themes include special formatting only for Note and Warning. (I am using one of the preinstalled themes, Classic.)</p>
  
  <p>I have two questions: </p>
  
  <p>1) How can I customize the color behind Warning in my documents? </p>
  
  <p>2) How can I add a formatting style for Caution? </p>
  
  <p>I see that these all end up with tags like <code>&lt;div class="admonition warning"&gt; ...</code> in the HTML output. But I can't find where the formatting for that class is defined. Is it in a stylesheet? Is it in a layout.html file or some other file?</p>
  
  <p>Is there anything that explains how the various files in themes actually interact with each other? I haven't found a good primer. (I am no expert on css-based HTML either, so maybe that's part of the problem.)</p>