I'm using the standard tell-a-friend code from the EE Docs. Where do I find the "thank you" page template that comes up after emailing an entry using the tell-a-friend tag? I'd like to style it to look like the rest of my site.
You can use the
return parameter on the
exp:email:tell_a_friend tag to specify a template you want to use as the confirmation (thank you) page. It can be any template you want, customized as needed.
If you're talking about the "interstitial" page where a message is shown for a few seconds before redirecting, that is a system message and to customize it you'll need to go to CP > Design > Message Pages > User Messages or use an add-on like Custom System Messages.