I have now managed to get the content to stay inside the the containing div but only as a single column and not as two columns. the code the displays as two columns but with third channel field item outside the containing div:
This code is from a template (stories), that is embedded in the index template
<!-- content_bg -->
<div class="content_bg">
{embed="twayf/stories-video_gallery"}
</div>
<!-- end right container -->
This code is on the stories-video_gallery template:
<style type="text/css">
#videogallery{padding: 10px; width: 700px; }
#vg_column {
float:left;
width:340px;
margin-right: 10px;
margin-bottom: 10px;
}
#videogallery img {margin-bottom: 5px;}
#videogallery img:hover {width: 338px; height:251px; border: solid 2px #65ba75;}
</style>
<div id="videogallery">
{exp:channel:entries channel='video_gallery_stories'}
<!-- left column -->
<div id="vg_column">
<h2>{title}</h2>
<p> <a href="http://www.youtube.com/embed/{video_id_story_gallery}?version=3&hl=en_US&rel=0&autoplay=1">http://img.youtube.com/vi/{video_id_story_gallery}/0.jpg</a><br />
{video_description}<br />
</div><br />
{/exp:channel:entries}</p>
<p></div>