Multiple grid with different style


I would like to use two grids on same page with different style. I read a lot of from this theme but I didn’t find solution.
So I have an html file that is contains a dom-module tag with attribute theme-for=“vaadin-grid” and I use this to style a grid’s thead, td, tr parts. According to the vaadin docs the dom-module affect to all vaadin-grid element in this case.
I tried to create own grid component that is extended from grid but this not working - I suppose because the own component name’s was different from vaadin-grid.

Could you help me? How can I create own component from grid with custom tag or how to use two grid component with different style?

Thank you!