How to add a css class and give style in asp.net page or its code behind

[foombbartLema]

I am using a asp.net aspx page which has a master page. There is a custom control and it does not have cssClass attributes or style attribute. It autogenerates div ids and i want to assign a css just for that aspx page. The tricky part is the id generates by other pages as well. I cannot set this css in my stylesheet because of that reason. any help, greatly appreciated!