You can edit the style of your tables by going to Edit Design > Table Styles
Select either the header row, body row or footer row to begin editing properties.
With an element selected, you can change the background color, border size and color. (The text styles are defined under Typography).
If you have the body row element selected, there is an additional option: Alternate rows. If you want zebra striping (every other row is different) check this ON.
Once it's check on, you will be able to define the background color, border size and border color of both the odd and even rows.