That is technically possible but X and the IndexVentures site is structured differently so modifying it to look the same would be quite involved. With that said, you may need to hire a WordPress developer to do the job for you as it would fall beyond our scope of support.
Hey, I have a good developer but he’s not familiar with the X theme. Can you explain a bit about how it would be done and I could pass that on? Thanks for your help….
X is a very developer friendly theme. He could start by adding some CSS to Customizer > Custom > CSS to make the menu look similar. It shouldn’t be very hard for someone with skills.