Simple gradient nail art pictures in 2015 style

Quick answer：

Simple gradient nail art refers to a design technique where different colors gradually blend together on the nails. The term '2015 style' indicates that this design was popular or fashionable during that year. In 2015, gradient nail art became a major trend, with many variations and color combinations being explored. This style often involved using two or more contrasting colors to create a smooth, flowing transition from one color to another.