title: CSS attribute selector for non-empty attributes
body: <p>Is there a CSS selector that applies to <em>non-empty</em> attributes? Using <code>:not([Data-Attribute=''])</code> matches if the attribute is <em>non-existing</em>, too. </p>
  
  <p>I'm looking for something like <code>[Data-Attribute!='']</code>.</p>