Can't go wrong with Black or white

Black

White — and only because of where this screen actually gets looked at. Black is the nicer object on a desk, but a run tracker is read outdoors at arm's length in daylight, often through a sweaty screen with auto-brightness maxed, and dark backgrounds lose that fight badly. White...

Adorable design! Fresh and vibrant!

Nice work as usual! High-contrast dark states always bring out the best in data-dense UI layouts.

black one is great

For something you'd glance at mid-run in bright sunlight, my gut says white wins on legibility even though black looks sleeker sitting still. Are you designing this with outdoor use in mind, or is it mostly an indoor treadmill scenario?

both's simplicity are fabulous, but black wins here for me!

Black

Light mode for bright outdoor readability, but dark mode looks so clean for evening tracking! Depends heavily on the primary use case, but both looks are super polished.

you should have both for better UX

both look cool!

White looks better

Black for me. This reads as a running or workout tracker, and dark mode is easier on the eyes outdoors and better for glanceable metrics mid run.