Iv had this for at least seven days now and was checked today, they said it was perfectly fine! Just if they show other symptom!
Generally nothing to worry about if they seem fine and have no other symptoms.
I went to the doctor's today for one of my babies and mentioned she'd had green poos (dark not bright, though) and the doctor said she'd been drinking her milk too fast and it was green because it wasn't being digested properly so to make sure I pause her in between feeds, not sure if that helps 😊
https://www.pregnancybirthbaby.org.au/baby-poo-guide might be useful!