title: css for "all available width"?
body: <p>How can I specify that the width of a given element should be the "maximum available width", once its horizontal margins, its parent's horizontal padding, etc. are taken into account, and also assuming that the parent's width has not been specified explicitly?</p>
  
  <p>BTW, contrary to what one may think, <code>width:100%</code> is <em>decidedly not</em> the answer to this question (see <a href="http://www.impressivewebs.com/width-100-percent-css/" rel="nofollow">here</a>, for example).</p>
  
  <p>(There are many questions on SO that seem to ask the same thing as this one, but on closer inspection one finds that those are far more specific than this one, and their answers depend on very specific details of some code presented in the question.  Here I'm looking for as general as possible an answer.)</p>