Colors in CSS: Hello Space-Separated Functional Color Notations

In CCS there are several ways to notate color values. Basically we have three options:

  1. Using a Keyword: e.g. black
  2. Hexadecimal Notation: e.g. #000000, #000, and #000000FF
  3. Functional Notation: e.g. rgb(0, 0, 0), rgba(0, 0, 0, 1) (and the hsl()/hsla() variants)


The CSS Color Module Level 4 specification adds an extra variation to the Functional Notation: it allows you to separate the individual RGB (or HSL, etc.) values using spaces instead of commas, e.g. rgb(0 0 0);.

rgb(), rgba(), hsl(), and hsla() have all gained a new syntax consisting of space-separated arguments and an optional slash-separated opacity.

Above that rgba() has become an alias for rgb(), so our colors in CSS – using the Functional Notation – will soon look as follows:

/* Before: Comma-Separated Functional Color Notation */
div {
  color: rgb(0, 0, 0);
  color: rgba(0, 0, 0, 1);

/* After: Space-Separated Functional Color Notation */
div {
  color: rgb(0 0 0);
  color: rgb(0 0 0 / 1);
  color: rgb(0 0 0 / 100%);


You should start writing your colors using this new syntax today, as:

  1. The syntax is already supported by all major browsers.
  2. New color functions – such as lab(), lch() and color() – will only support the space-separated syntax

Your preprocessor can take care of older browsers such as IE11 😉


Did this help you out? Like what you see?
Thank me with a coffee.

I don\'t do this for profit but a small one-time donation would surely put a smile on my face. Thanks!

BuymeaCoffee (€3)

To stay in the loop you can follow @bramus or follow @bramusblog on Twitter.

Published by Bramus!

Bramus is a frontend web developer from Belgium, working as a Chrome Developer Relations Engineer at Google. From the moment he discovered view-source at the age of 14 (way back in 1997), he fell in love with the web and has been tinkering with it ever since (more …)

Unless noted otherwise, the contents of this post are licensed under the Creative Commons Attribution 4.0 License and code samples are licensed under the MIT License

Leave a comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.