Applying Css To Gridview Table Thead/tbody

I have tried using my theme’s stylesheet to apply style to the auto-generated thead/tbody of the gridview however it won’t catch.

I have tried:

#outsideDiv > tbody

div#outsideDiv > tbody

#outsideDiv > table > tbody

div#outsideDiv > table > tbody

#outsideDiv tbody

All without success. I suspect it because it seems the table is generated post-page-load but I am having trouble tracing through the code.

Any suggestions?

My goal is to apply max-height and overflow-y to JUST the tbody of the gridview.