Active job

Building a cat barrier on an apartment deck to keep the cat confined

I have an apartment with a wrap around deck that currently would not keep my cat contained. i need a barrier similar to a gate in one area and a height barrier to stop said cat escaping. as you can see in the picture the gate/barrier is not wide but the cat can still jump onto the barrier and move onto the rest of the deck. The top part of deck fence is a plastic and we are not allowed in the body corp to make changes to that. I hope asap for the job - I am a principal and have little time to do any of this myself in this current situation. REally appreciate any help you can provide