I have two css files having the following class definition
default.css ( Loaded First )
#order-standard_cart .products .product header {
background: #f8f8f8 none repeat scroll 0 0;
border-radius: 3px 3px 0 0;
margin: 0 1px;
padding: 10px 20px;
position: relative;
}
custom.css ( Loaded 2nd )
#order-standard_cart .products .product header {
background: #7EBBF3 none repeat scroll 0 0;
}
Even after loading second, the background property is not getting applied on any of the browsers and only the first CSS file is being applied.

