Detachment is the ability to enjoy the world without being enslaved by it. It is the absence of craving and aversion.
Krishna teaches Arjuna that while the world is temporary, the Soul is permanent. Attachment to the temporary leads to grief.
Caring deeply about people and work, but not falling apart if things change or go away.
Healthy emotional boundaries and resilience.
Investing in a project with all your heart but accepting its failure with a calm mind to learn for the next one.