Red monochrome gradient nail art picture 2015 style

Quick answer：

This refers to a type of nail art design featuring a gradient of red colors, typically in a single shade, that was popular in 2015. It involves applying different shades of red on the nails to create a smooth, flowing transition between them, usually with a focus on the red hue. This style is a part of the broader category of nail art trends and can vary in complexity from simple to intricate designs.