.g  { border-style:solid; border-bottom-width:1px; border-color:Green; }
   .b  { border-style:solid; border-bottom-width:1px; border-color:Blue; }
   .r  { border-style:solid; border-bottom-width:1px; border-color:Red;    }
   .o  { border-style:solid; border-bottom-width:1px; border-color:Orange;    }
   .y  { border-style:solid; border-bottom-width:1px; border-color:Yellow; }