Shade into
Definition 1 of 1
Pro Tip 1/3Visual Transitions
Used to describe visual changes, often seen in nature or art. 
The painter's use of color made the scene shade into a lively spring morning.
Pro Tip 2/3Metaphorical Use
Can signify a change in situations, emotions, or relationships in a figurative sense. 
Their friendship slowly began to shade into rivalry as they competed for the same role.
Pro Tip 3/3Subtle Change
Implies a gradual and almost unnoticeable transition, rather than an abrupt switch. 
The discussion began to shade into an argument without anyone noticing.