[tony_sologubov]

I just made a diff of which files are included and it looks like these css files might be a culprit:

<link  href="skins/custom_skin/default/en/modules/QSL/Banner/banner-system.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/items_list/items_list.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/pager/pager.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/common/grid-list.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/items_list/product/products_list.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/modules/XC/ProductComparison/compare/products/style.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/items_list/product/quick_look.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/labels/style.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/modules/CDev/ProductAdvisor/style.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/modules/CDev/Sale/style.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/product/details/parts/gallery.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/product/quantity_box/quantity_box.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/product/details/parts/attributes_modify/style.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/modules/XC/FreeShipping/label/style.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/modules/XC/Reviews/average_rating/style.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/modules/XC/Reviews/vote_bar/vote_bar.css?1418089607" rel="stylesheet" type="text/css" media="all" />
<link  href="skins/default/en/modules/XC/Reviews/form_field/input/rating/rating.css?1418089607" rel="stylesheet" type="text/css" media="all" />

Now you can try to remove all of them from your test.html and check whether it fixes the problem. Then, you should start adding them one by one and once the problem happens again, you will find an exact CSS file that causes the problem.