Automatic Responsive theme or custom ?

Hi, I am having trouble altering a website (using the rockstar pro theme) . I am trying to make the website work one way when people look at it through a desktop and another way when they see it through their cell phone. For example if someone were to view it from a desktop they would see gifs and various videos with a lot of content that took more power to load. But if they choose to view it through a mobile device , they would see different content that was more minimal (no gifs, no videos, just writing and pics). Does rock star pro responsive theme have this ability? If so how can I utilize it so there is different material when people look at it on different platforms? If it doesn't work with rockstar pro is there a way to add it on? Thank you for your time and effort Sincerely,