Social media dashboard with theme switcher

Feel free to give any feedback. It will be appreciated.

There are some things I couldn't do it. - Background has 2 colours. I used linear-gradient function to do it. Problem is in the mobile version, top colour has a border radious and I couldn't get the effect. Some way to do it?

- I wanted to use transition property to give effect when I flip the switch. Problem is that button, background and one of the border's card have a linear-gradient so transition doesn't work. Is there some way to get the effect??