Pour the colours between bottles until each one holds a single colour.
Pour is a calm water sort puzzle. Tap a bottle, tap another, and the colour pours across. Sort every bottle into a single colour to finish the level. There is no timer and no rush, and every level can be solved.
Sorting things into order is quietly satisfying, and Pour has no clock to beat. Take as long as you like; there is always an undo. Why a five-minute break works.