It seems you are using floating menu plugin, so it would be better if you consult to respective plugin author, they might give you appropriate solution.
Regarding to content area, it seems you are using page editor itself to build page template. So you need to write proper media query for mobile devices. You can see the reference here: https://css-tricks.com/snippets/css/media-queries-for-standard-devices/
You can take help of any page builder( site origin, live composer and many more ) if you are not familiar doing css.
Sorry for the inconvenience , As this requires custom work, we do not provide support regarding to customization.