title: CSS RGBA border / background alpha double
body: <p>I'm working on a website that has a lot of transparency involved, and I thought I would try to build it entirely in RGBA and then do fallbacks for IE. I need a "facebox" style border effect, where the outer border is rounded and is less opaque than the background of the box it surrounds.</p>
  
  <p>The last example from <a href="http://24ways.org/2009/working-with-rgba-colour" rel="noreferrer">http://24ways.org/2009/working-with-rgba-colour</a> seems to suggest that it's possible, but I can't seem to get it to work. When I try the following:</p>
  
  <pre><code>&lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;
  
  &lt;html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"&gt;
  &lt;head&gt;
   &lt;meta http-equiv="Content-Type" content="text/html; charset=utf-8"/&gt;
  
   &lt;title&gt;RGBA Test&lt;/title&gt;
   &lt;style type='text/css'&gt;
     body {
       background: #000;
       color: #fff;
     }
     #container {
       width: 700px;
       margin: 0 auto;
       background: rgba(255, 255, 255, 0.2);
       border: 10px solid rgba(255, 255, 255, 0.1);
       padding: 20px;
     }
    &lt;/style&gt;
  &lt;/head&gt;
  &lt;body&gt;
    &lt;div id='container'&gt;
      This should look like a facebox.
    &lt;/div&gt;
  &lt;/body&gt;&lt;/html&gt;
  </code></pre>
  
  <p>It seems like the background "extends" underneath the border of the element, which causes the pixel values to get added together. Thus, when both the background and the border are semi-transparent, the border will ALWAYS be more opaque than the background of the element. This is exactly the opposite of what I am trying to achieve, but it seems like it should be possible based on the examples I've seen.</p>
  
  <p>I should also add that I can't use another element inside the container, because I'm also going to use a border-radius on the container to get rounded corners, and webkit squares the corners of the child elements if they have a background assigned, which would essentially mean a rounded outer border with square contents.</p>
  
  <p>Sorry I can't post an image of this... Apparently I don't have enough rep to post an image.</p>