/* Related items */
.itemRelated { overflow: hidden; margin: 0 0 84px; }
.itemRelated h3 { font-weight: 300; color: #fff; margin: 32px; padding: 0; font-size: 1.875em; }
.itemRelated ul { margin: -0.625em -1.625em 0; }
.itemRelated ul li { display: block; padding: 1.25em; overflow: hidden; border-radius: 3px; float: left; z-index: 3; width: 20%; position: relative;}
.itemRelated ul li:last-child { margin: 0; padding: 0; display: none;}
.itemRelated ul li:first-child { }
.itemRelated ul li .itemRelImageBlock { position: relative; padding: 0 0 75%; overflow: hidden; overflow: hidden;}
.itemRelated ul li .itemRelImageBlock img { min-width: 100%; position: absolute; left: 0; top: 0; height: auto; min-height: 100%;}
.itemRelated ul li .itemRelContent { overflow: hidden; }
.itemRelated ul li .itemRelTitle { display: block; font-size: 1.5em; margin: 0 0 10px; letter-spacing: -1px; }
.itemRelated ul li .itemRelIntrotext p { margin: 0; color: #fff; }
.itemRelated ul li .itemRelCat a { color: #fff; color: rgba(255, 255, 255, 0.5); }
.itemRelated ul li .itemRelCat a:hover { color: #f7ed05; }
@media screen and (max-width: 600px) {
.itemRelated ul li { width: 50%; }
}
@media screen and (max-width: 400px) {
.itemRelated ul li { width: 100%; }
}
This is the code for transforming the related items into a grid. You can always add some padding and play around with it a bit.
Keep a backup of your template.css file and replace the related items block with this one.