Green does not mean available
The traffic light is the reflex, and it fights you. Red reads as a warning, so your sold inventory looks like a problem instead of proof that people are buying here. Green reads as neutral background because every interface on earth uses it for "fine, carry on."
Give available the loudest colour you have, which is usually your brand accent. Let sold go quiet without disappearing. And never carry the meaning in colour alone, because roughly one man in twelve cannot separate your red from your green.




