Fix to layout breaks on examples and stories.

[atomworks]

Removes the flex from the #root selector which was breaking the layout of some examples and stories. It was added as part of a fix to the layouts not spanning the full height of the container and backgrounds being cut off when scrolling, however it seems that this flex on #root was redundant.

[atomworks]

This latest update does the following:

• Moves the body background to the BaseStyles helper (which is probably where it should have been already).
• Adds some CSS changes to the examples styles.ts to restore scrolling.
• Also removes the background gradient for this to avoid background bug.

As our UI work is mostly intended to work in our GlobalUI module, the example shows how you can set up your code if you're working outside of that context.

The background gradient was a nice to have for these but isn't essential for examples. To have this working properly here would take additional examples refactoring that I feel is time best spent elsewhere at the moment.