Ищи
topic {
display: block;
height: 23px;
font-family: 'Roboto', sans-serif;
font-size: 12px;
width: 180px;
padding: 5px;
position: relative;
left: 0px;
color: #7b7b7b;
margin-top: 2px;
margin-bottom: 2px;
border-left: 5px solid #5B7288;
background-color: #f2f2f2;
}
Меняй цвет: background-color: #f2f2f2;