Hello everyone

I've searched the internet and found something on peltiertech (before posting my question) that related to what I want but I can't seem to get it to work. I have an xy scatter that has negative and positive y values on it with an x-axis which has dates. What I would like to do is make the horizontal x-axis line (where y values would be 0) BOLDED so it stands out.

So you can visualise it easier:

Pretty much I have a graph that is connected to a database. On the x-axis we have the dates of special promotions our company runs which we advertise before it begins. Then on the y-axis we measure averages of how many days before or after a promotion a begins that customers sign up. This is to measur ethe effectiveness of our avetising and to see anticipation.

Regards,
james