Highlight particular member of Chart using CSS

Hi Experts,

Below is my chart output in DS 1.2. Source is Bex query.

As you can see in chart, there is a red line on the period 2013.009. We should show this kind of straight dotted line on the period entered by user in Prompt. Is it possile to achieve using CSS? If yes, could you pls throw light on the respective code.

2013.009 is Fiscal year period user enters in Prompt. Hence the red line should be dynamic on the periods entered by user.

Thanks & Regards,

Kesavan.