Need suggestions for Railing!

I have a very senior cat who can’t see, bad balance, and falls off stuff very easily… I just had to move into a new place that has stairs and railings! She has already almost fallen through the gap at the bottom of the railing. I know she’s gonna hurt herself if I don’t keep the gap blocked (currently have blankets and pillows blocking) Looking for ideas on how to close the gap with it still looking nice!