GroupItem uses wrong color on hover #79
Description
When hovering over the GroupItem component, the current style uses a darker shade of the theme color. This is correct only if the button is currently selected. If the button is not currently "selected" it should use a very light shade of the theme color (maybe 50) on hover, as shown in the settings NavButton.
Consider refactoring the logic of GroupItem and NavButton to a separate "Button" component that has some "active" state. Then, style this button directly by extending Chakra's theme. This will make useColorScheme obsolete.