how to show the unread dialy report with highlihgt color???

Question

I want to highlight the unread records  with  color in gridview...For ex:I have 4 reports in my Grid view,those are unread records so I want to highlight ,after view the record it should not be highlight.I tried same thing but in my Grid I have 4 reports but only one record is  highlighting..Can any one help me how to write the code for this???that is mvc project and I'm using the css to highlight the color like

 

.ColorChange

{

font-weight: bold !important;

background:#C2E0FF !important;

}

and I'm calling this  in code..but it's not working properly Can any one help me  please????