Pigments will scan source files in your project directories looking for colors and will build a palette with all of them. Then for each opened file, it will use the palette to evaluate the value of a given color. The legible source paths can be defined through various settings either at the global or per project level. By default colors in every file will be highlighted, to limit the display of colors to the desired filetype only please see the Defining Where Pigments Applies below. Pigments supports out of the box most of the color transformations functions and expressions of the three biggest CSS pre-processors out there, namely LESS, Sass and Stylus. However, it doesn't mean pigments is able to parse and understand all of these languages constructs. For the moment, Pigments' aim is to support the widest range of usage, even if it implies reducing its ability to parse certain complex constructs. You can refer to the parser specs for an exhaustive list of the supported expressions.