The short answer is . The longer, more helpful answer is: But you can build one yourself.
to dim the screen and remove blue light during late-night sessions. Why You Can't Enable the "UI Theme" Switch How To Customize Pro Tools UI and Color Coding pro tools 12.5 dark mode
Dark UI themes were introduced much later (Pro Tools 2020+). In PT 12.5, the interface is light gray/beige by default. The short answer is