How to add css text properties to breadcrumb text

I would not add this to the breadcrumb markup itself (e.g. don’t add this to the breadcrumb templates). Instead, you should target the breadcrumbs in the trail and either modify your theme’s (or child theme if you are using one) style.css.

Depending on how you are calling the breadcrumb trail, you probably can target the .breadcrumbs class to get the container of the entire breadcrumb trail. I suggest using your browser’s built in inspector to test styles out, and investigating what is available to you.