HTML source code to set for laptop and mobile

Hi! What you're looking for is a CSS media query. It looks something like this:

     (max-width: 768px) {
.container {
width: 300px;
} 
}

I'm sure you can find lots of detailed info on YouTube.

Edit: that first code line is supposed to say MeDia​ (max-width: 768px)

-- ironically the code input window is messing up my code. :D

It thinks I'm tagging somebody named "MeDia". Hi MeDia​!