Pls. Help, Setting row color doesn't work when column color is set

I set column style like this

#myGrid .aw-column-0 {width: 100px;border-right: 1px dotted #ccc;text-align:left;background-color:#CCCCCC;}

It works fine. but when I want to set some row's color like this

#myGrid .aw-row-1 { font-weight:bold; background-color:#FFFF00; color:#0000FF;}

On column-0 of every row, the color still be "#CCCCCC". I need the color on row 1 to be "#FFFF00" . it couldn't override the column style.

Pls. Help. Thank you.