title: Using relative URL in CSS file, what location is it relative to?
body: <p>When defining something like a background image URL in a CSS file, when using a relative URL, where is it relative to? For example: </p>
  
  <p>Suppose the file <code>/stylesheets/base-styles.css</code> contains: </p>
  
  <pre><code>div#header { 
      background-image: url('images/header-background.jpg');
  }
  </code></pre>
  
  <p>If I include this style-sheet into different documents via <code>&lt;link ... /&gt;</code> will the relative URL in the CSS file be <strong>relative to the stylesheet document</strong> in <code>/stylesheets/</code> or <strong>relative to the current document</strong> it's included to? Possible paths like: </p>
  
  <pre class="lang-none prettyprint-override"><code>/item/details.html
  /about/index.html
  /about/extra/other.html
  /index.html
  </code></pre>