Install a .HTC file?

https://css3pie.com/documentation/getting-started/

The problem is it does’t render correctly in WP though if you put it inside the theme.

For example, I have it working here: https://lucaswynne.com/ in the class .count – that class creates a circle around the number of comments display in the upper right hand corner of each excerpt. But instead it just disappears in IE.

Hi, sure you have probably figured this out already, but until you have figured out where the page is rendering from, you will have very little success. I know its not ideal, but just for testing, use the absolute path rather then relative.

behavior: url(https://my.domain.com/PIE.htc);