Styling based on instance data

Itwouldbeniceif you could use CSS to style the background of repeat
items yellow if they are "selected" in the data using some magical CSS
XPath selector:

<style type="text/css">
 
repeat.lines::repeat-item[xpath(boolean-from-string(instance()/lines/lin
e/@selected))] { background-color: yellow; }
  ...
</style>

<repeat class="lines" nodeset="lines/line">
  <input ref="@selected">
    <label class="columnHeader">X</label>
  </input>
  <output ref="date">
    <label class="columnHeader">Date</label>
  </output>
  <output ref="name">
    <label class="columnHeader">Name</label>
  </output>
</repeat>