You probably noticed that Twitch overhauled their design and changed some pretty important things like the chat. It's now... black. Black as in 
pitch black. 
Since they changed pretty much every color, the Twitchy theme will get a complete redesign sooner or later. Probably later, because no one knows if they're planning on changing even more major things.
Here's a little workaround to make the chat less prominent like it was before:
Click the 
⚙️ in your chat
Make sure to change to "Switch to Non-Mod Settings" or you won't be able to access the "FrankerFaceZ Control Center" found at the bottom of the settings
 
	
	
	
		
		
		
		
	
	
Click on 
FrankerFaceZ Control Center
Search for 
background in the top bar
Click on 
Theme under
 Appereance
Enter 
#121114 in the 
Background input field
	
	
	
		
		
		
		
	
	
Here's a screenshot so you know what to expect with this change.
Left = Before | Right = After
	
	
	
		
		
		
		
	
	
The chat looks way better and pretty similar compared to before, but the other panels like "Stream Information" and "Twitch Stats" are a tad brighter. Not much we can do about this.
I've talked with the lead developer of FrankerFaceZ and asked him if it would be possible to change the docks and chat separately since that's not possible atm. He has a lot of work at the moment but he keeps it in mind for a future update. If he's taking too long, I'll just update my theme and hope that Twitch won't screw me over.
Again: This is a workaround and only temporary. Expect BIG changes with this theme!
I hope that this little update helped you with Twitch's "interesting" style decision. 
~Fabi