Enter control center and personalization.

Set one window theme. You can select light theme, dark theme or auto.

"Auto" means changing window theme automatically according to the sunset and sunrise time. After sunrise, it is light theme; after sunset, it is dark theme.

There are 9 accent colors.

You can adjust transparency and corner.

Set Scale or Magic Lamp when the window is minimized. 

Choose an icon theme that you like.

Now, select a set of cursors. 

Change the font and font size for the system that you like.