Manage landing page using React and SCSS

Couldn't find a way to remove ability to scroll when menu on mobile is active so I added a Click Outside function. I know there's a better way to do this but it's all I came up with. Also, I'm new to react-slick and couldn't find a way to make it look exactly the same but I think this realization of slider is appropriate. My main problem is I don't know how to display one slide on mobile and more on desktop version. Is there something like @media (min-width: 426px) but in HTML? I'll work on tablet design later. I'm really open to critique so give me all you have! c:

upd: I just noticed that text isn't actually black and I forgot to do any hovers and messed up margins so my solution is kinda short compared to design. I'm gonna fix it tomorrow and update solution