Changing colour of the grid number header column

I have seen how to change the colour of the headers along the top of a grid control. I would like to change the left header, that is, the grey numbers going down the left side of the grid which number each record: 1,2,3 etc. This is not 'column0' because that is the first data column, so how are the colours/fonts set for these? ( I'd prefer to use the style sheet method of setting them as in: ).

#myGrid .aw-row-selector {background: red}

There is a sample file which shows how to style different parts of the grid - /examples/quickref/grid.htm