You can style them with CSS to improve the default appearance. However, make sure you don’t get carried away and use tables for layout—for accessibility reasons, keep them strictly for data.

Using CSS to Eliminate Tables. CSS or Cascading Style Sheets has opened up tremendous possibilities for improving web site designs, web page layouts and adding new features.

Many e-mail clients don't respect advanced CSS. I'm 0% surprised to find that nth-row is one of those. The solution is to just apply a style by hand to every other row, either with a class or ...