How To Define An Array Of Colors With CSS — Smashing Magazine

CSS is mainly known as a language based on a set of property-value pairs. You select an element, define the properties, and write styles for it. There’s nothing wrong with this approach, but CSS has evolved a lot recently, and we now have more robust features, like variables, math formulas, conditional logic, and a bunch of new pseudo selectors, just to name a few.

What if I tell you we can also use CSS to create an array? More precisely, we can create an array of colors. Don’t try to search MDN or the specification because this is not a new CSS feature but a combination of what we already have. It’s like we’re remixing CSS features into something that feels new and different.

For example, how cool would it be to define a variable with a comma-separated array of color values:

--colors: red, blue, green, purple;

Even cooler is being able to change an index variable to select only the color we need from the array. I know this idea may sound impossible, but it is possible — with some limitations, of course, and we’ll get to those.

Enough suspense. Let’s jump straight into the code!

An Array Of Two Colors

We will first start with a basic use case with two colors defined in a variable:

--colors: black, white;

For this one, I will rely on the new color-mix() function. MDN has a nice way of...