selected row background color not working and also if i do alternative record color not working properly for mouse hover

[Bichitra73]

existing style format below
.vcolumn{
display: inline-block;
padding: 5px;
border-right: 1px solid black;

}
I created new style
.vcolumnAlt{
display: inline-block;
padding: 5px;
border-right: 1px solid black;
background: gary (added)

}

.data-grid > .container > .vcolumnalter:hover{
background: -webkit-linear-gradient(black,gray);;
}

in HTML I use

{{row[key.name]}}

issue# 1: mouse hover not working for dynamically added for vcolumnAlt.
2nd how to make record selected with different color if i click the record untill i click other row