Overview page shows unwanted text – the sequel

I set up the Events Calendar about a year ago. There was a sentence under the header that read ?“It seems we can’t find what you’re looking for. Perhaps searching can help.”
I got excellent help from support – a CSS snippet that handled the issue.
After fixing some bugs the problem has come back, and the old snippet doesn’t work anymore.

What do I do to remove that sentence again?:)?

The page I need help with: [log in to see the link]