CSS Custom Functions are coming … and they are going to be a game changer!

Chrome is currently prototyping CSS Functions from the css-mixins-1 specification.A custom function can be thought of as an advanced custom property, which instead of being substituted by a single fixed value, computes its substitution value based on function parameters and the value of custom properties at the point it’s invoked.

Here’s a very simple example (taken from the spec) that should give you an idea of what a custom function looks like:

@function --negate(--value) {
result: calc(-1 * var(--value));
}

Source: CSS Custom Functions are coming … and they are going to be a game changer! – Bram.us