title: How does the z-index property really work?
body: <p>How does <code>z-index</code> actually work?
  Does it function on elements with no specified <code>position</code>?
  Does it favor elements (i.e. make them on top) that have a specified <code>position</code>?</p>
  
  <p>Do the numbers have to be negative like this? </p>
  
  <pre><code>&lt;div style='z-index:-2;'&gt;below&lt;/div&gt;
  &lt;div style='z-index:-1;'&gt;less below&lt;/div&gt;
  &lt;div style='z-index:0;'&gt;on top&lt;/div&gt;
  </code></pre>
  
  <p>Or not? Would all positive numbers (in increasing value) end up with the last being on the top, the middle in the middle, and the first on the bottom?</p>