Custom button on the External Career Site

Content

As the Title reads, I'm looking to check if it is possible to create a new button on the External Career Site, with a link to redirect it to a Custom URL

Please let me know if this is feasible. If it is, can you please help me with the working copy of the CSS snippet that we can utilize?

PS: I understand that there is a functionality to add headers and footers; this post does not refer to them

Version

20C