CSS is doesn't load when "Aggregate and compress CSS files" is enabled

When CSS caching and aggregating of CSS files is enabled in Drupal's performance options, mytube.css is not bundled in with the rest of the cached files. As a result, the play.png thumbnail appears below the video thumbnail instead of overlaying it, but disabling the aggregation of CSS files then clearing the cache will fix it (at the cost of performance). Effectively, this leaves users with the choice of faster performance by caching OR aesthetic display of processed video thumbnails.