@if The @if directive takes a SassScript expression and uses the styles nested beneath it if the expression returns

scale_color($color, [$red], [$green], [$blue], [$saturation], [$lightness], [$alpha]) Fluidly scales one or more properties

append($list, $val, $separator:auto) Appends a single value onto the end of a list. Unless

@error The @error directive throws the value of a SassScript expression as a fatal error, including a nice stack

Pattern: [attr=val]   Definition: The [attr=val] selector matches

quote($string) Add quotes to a string if the string isn’t quoted, or returns the same string if it is.

Pattern: :nth-last-of-type(Nth) The argument Nth is of the following format:

lightness($color) Returns the lightness component of a color. See

variable_exists($name) Check whether a variable with the given name exists in the current scope or in the global scope.

Pattern: :link   Definition: The :link pseudo-class