Does op have tmobile gnote3? Are you rooted and have recovery? If so, goto dev section and look for stainless rom. International rom has more black theming. Email app does not though.
Sent from my SM-9005.
From Oka1 : Yes I have a TMO Note 3 rooted, and have recovery, using Jedi V2 right now, One thing I have found is everytime I modify the phone e.g. flash a theme it breaks the root and SuperSu has to be flashed before rebooting.