Larger font for Secret could be helpful
I like the nice logos on the Authenticator UI. That makes it easy to find the tool you're looking for.
The secret however, is displayed in the usual small font, which makes it a bit hard to read it, especially when you need to type it (e.g. when I need to enter an OTP on my TV set on the wall). Also, using bigger letters for the one-and-only important information of this app help elderly people (like me) to read stuff.
I appreciate the way the Authenticator extension does it: Large letters to display the secret, light blue, and flashing red-ish before they start to lose their validity. Something like that would be nice!