change icon for resizing in react-modal-resizable-draggable

i am using the react-modal-resizable-draggable modal from:
https://www.npmjs.com/package/react-modal-resizable-draggable
and i am facing a problem while trying to change the little tiny icon that is in the bottom right to a different icon from “kendo”.
the icon o want to change

I would like to know what is the right way to do so.

Is there any way to add a class only to the icon without doing dumb manipulations on the dom like: Document.querySelector() etc.

Thanks for your help!!!