How to add CSS class for first thumbnail in Gallery Modx?

Question

css

We need to add a css class for the first thumbnail in the output. For example, getresources can have a separate template for each n-resource. Wayfinder also has similar functionality. Question: how to add css class to first thumbnail using gallery.
Gallery call:

Chunk GalRandomItem:

<article class="one_quarter">
<a href="" class="fancybox" rel="external">
<div class="push10"><img src="" alt="" title="" /></div>
<p></p>
</a>
</article>

Answer 1

You can try with CSS:

.gal-item:first-child {
...
}

Answer 2

then use the itemCls parameter

Answer 3

added styles