We actually no longer do prefix-based replacement in phx_component_helpers 
extend_class instead switched to a declarative mode where you can use a bang❗️operator to remove default classes, such as:
<.button class="!m-* m-12 !hidden block"/>
to override default margin and display properties.
I once opened a topic on this specific issue here: Need help with an issue on my phx_component_helpers library
