Menu changes

Hi guys.

I need to change these things in menu (i´m using sidebar menu):

1 - Change font color on hover and active page
2 - Change font size on main menu

3 - ... and now, the tricky one: is it possible to use sidebar menu only at bigger screen sizes and top menu for lower screen sizes?
4 - If nr. 3 is not possible, how can i call the responsive (mobile) menu sooner?

5 - In Sidebar menu, the search box doesn´t look very nice as a dropdown, could we target menu link to the overlay one, like in top menu ? Or even just the imput box, allways visible, not as a dropdown.

Thank you.