[Plugin: Broken Link Checker] Link tweaks

Hello, for some reason Link Tweaks CSS styles does not work for me. My broken youtube video urls shows up as it is “http://www.youtube.com/watch?v=vqqxB_r7VoQ”

I have a custom theme and not sure if I need to do anything extra to apply these Link tweaks css style ?

Thank you

http://wordpress.org/extend/plugins/broken-link-checker/