Distinguish between Test & Prod environments with Redwood?

Summary:

We are implementing the Redwood theme across multiple environments and due to the limited customisation available of the redwood theme, it's difficult to distinguish the environments with different colours. Has anyone come across any ways to do this?

Content (required):

We have tried the following options:

• Change colour behind the search bar via page composer (doesn't change the whole black banner at the top of the page)
• Add coloured emjois via the FND_BANNER functionality by adding a html code. This was temporary and revert to showing the code as the banner message
• Checked Appearance - although there are only default options there