[native] Misc color changes for light mode

Summary: Misc color changes to make light mode look more consistent with dark mode.

Test Plan:
Before:

After:

Before:

After:

Things look as expected.

Reviewers: tomek, marcin, ginsu, rohan, abosh, varun, O2 Blocking Reviewers, ashoat

Reviewed By: ginsu, O2 Blocking Reviewers, ashoat

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D5615