We have a site based on Porto theme as the theme was in 2014, very similar to now, mainly with styling differences.
Anyway as the menu was slightly customize when the site was built, in 2014, the responsive, see image attached. This need to be working again.
There are also a few other elements on the page that aren't 100% responsive, a booking app, and some tables which are only styled for pc view.
So small changes to CSS and the HTML needed only please.
Its based on Porto html theme - [login to view URL]
One of the most widely used themes in the world, so this should be very easy if you are familiar.
A one off but we need regular php and html help our various html and Wordpress sites, so bare that in mind.