css variables mdn - Brave Search

developer.mozilla.org › en-US › docs › Web › CSS › Guides › Cascading_variables › Using_custom_properties

Using CSS custom properties (variables) - CSS | MDN

Custom properties (sometimes referred to as CSS variables or cascading variables) are entities defined by CSS authors that represent specific values to be reused throughout a document. They are set using the @property at-rule or by custom property syntax (e.g., --primary-color: blue;). Custom ...

w3schools.com › css › css3_variables.asp

CSS Variables - The var() function

Static/Relative Position Fixed/Absolute Position Sticky Position Code Challenge CSS Position Offsets ... The var() Function Overriding Variables Variables and JavaScript Variables in MQ Code Challenge CSS @property

Videos

Introduction to CSS variables (CSS custom properties) [full tutorial] ...

How to use CSS variables like a pro | Tutorial - YouTube

December 20, 2021

The Ultimate Guide to CSS Variables - YouTube

Learn CSS Variables In 7 Minutes - YouTube

November 14, 2023

The CSS Variables Trick You’ll Wish You Knew Sooner - YouTube

February 25, 2025

CSS Variables Tutorial - YouTube

February 7, 2019

developer.mozilla.org › en-US › docs › Web › CSS › var

var() - CSS | MDN

The var() CSS function can be used to insert the value of a custom property (sometimes called a "CSS variable") instead of any part of a value of another property.

developer.mozilla.org › en-US › docs › Web › CSS › Reference › Properties › --*

Custom properties (--*): CSS variables - CSS | MDN

Property names that are prefixed with --, like --example-name, represent custom properties that contain a value that can be used in other declarations using the var() function.

developer.mozilla.org › en-US › docs › Web › CSS › Guides › Environment_variables

CSS environment variables - CSS | MDN

The CSS environment variables module defines the concept of environment variables and the env() function. Environment variables work similarly to custom properties and the var() function, except that they are globally defined; they are global variables scoped to the entire document.

developer.mozilla.org › en-US › docs › Web › CSS › CSS_cascading_variables

CSS custom properties for cascading variables - CSS | MDN

The CSS custom properties for cascading variables module adds support for cascading variables in CSS properties and lets you create custom properties to define these variables along with the mechanisms to use custom properties as the values for other CSS properties.

github.com › w3c › mdn-spec-links › blob › main › css-variables.json

mdn-spec-links/css-variables.json at main · w3c/mdn-spec-links

"summary": "The var() CSS function can be used to insert the value of a custom property (sometimes called a \"CSS variable\") instead of any part of a value of another property.",

Author w3c

developer.mozilla.org › en-US › docs › Web › CSS › Guides › Environment_variables › Using

Using environment variables - CSS | MDN

The CSS environment variables module introduces the concept of environment variables in CSS and defines the env() function to enable using environment variables. In this guide, we look at what environment variables are, the environment variables defined by the browser, and how to use environment ...

developer.mozilla.org › en-US › docs › Web › CSS › CSS_properties_and_values_API

CSS properties and values API - CSS | MDN

The CSS properties and values API module defines a method for registering new CSS properties, defining the property's data type, inheritance behavior, and, optionally, an initial value. This API expands on CSS custom properties for cascading variables module, which allows authors to define ...

Find elsewhere

Google Bing Mojeek

devdoc.net › web › developer.mozilla.org › en-US › docs › Web › CSS › Using_CSS_variables.html

Using CSS variables - CSS | MDN

CSS Variables are entities defined by CSS authors which contain specific values to be reused throughout a document. They are set using custom property notation (e.g. --main-color: black;) and are accessed using the var() function (e.g. color: var(--main-color) ;) .

developer.mozilla.org › en-US › docs › Web › API › CSSVariableReferenceValue

CSSVariableReferenceValue - Web APIs | MDN

The CSSVariableReferenceValue interface of the CSS Typed Object Model API allows you to create a custom name for a built-in CSS value. This object functionality is sometimes called a "CSS variable" and serves the same purpose as the var() function. The custom name must begin with two dashes.

web.dev › blog › @property: next-gen css variables now with universal browser support

@property: Next-gen CSS variables now with universal browser support | Blog | web.dev

CSS registered custom properties are a very powerful feature that extends the CSS language by providing meaning and context to CSS variables. Now, with @property landing in baseline, this CSS superpower is growing in strength. MDN Web Docs · @property: giving superpowers to CSS variables ·

caniuse.com › css-variables

CSS Variables (Custom Properties) | Can I use... Support tables for HTML5, CSS3, etc

MDN Web Docs - Using CSS variables · Polyfill for IE11 ·

developer.mozilla.org › en-US › docs › Web › CSS › Reference

CSS reference - CSS | MDN

Use this CSS reference to browse an alphabetical index of all of the standard CSS properties, pseudo-classes, pseudo-elements, data types, functional notations and at-rules. You can also browse key CSS concepts and a list of selectors organized by type. Also included is a brief DOM-CSS / CSSOM ...

blog.logrocket.com › home › how to use css variables like a pro

How to use CSS variables like a pro - LogRocket Blog

April 3, 2025 - According to the browser compatibility table of the official MDN documentation, the CSS variables feature is widely available in all popular browser versions released after April 2017.

developer.mozilla.org › en-US › docs › Web › CSS › Reference › Properties

CSS properties - CSS | MDN

A CSS property is a parameter used in a CSS declaration that lets you style certain aspects of selected elements. For example, the opacity property is used to set the opacity of a selected element, allowing you to control if content behind that element is visible:

mui.com › material-ui › customization › css-theme-variables › overview

CSS theme variables - Material UI

CSS theme variables replace raw values in Material UI components for a better developer experience because, in the browser dev tool, you will see which theme token is used as a value.

damiancyrus.com › blog › css-custom-properties

CSS custom properties (CSS variables) | damiancyrus.com

These variables offer significant benefits, such as improving code readability, facilitating maintainable global changes, and providing dynamic control over styles in a live environment.

medium.com › swlh › css-variables-618b156777ce

CSS Variables. Move over Sass, we have #CSS variables… | by Samantha Ming | The Startup | Medium

February 19, 2020 - Global scope will allow you to access the variable everywhere. Local scope will just be within your specific selector 👍 · :root { /* 1. Defining in Global Scope */ --color: red; /* 2. Available in all selector*/ color: var(--color); /* red */ }.local { /* 1. Defining in Local Scope */ --color: blue; /* 2. Scoped to the .local class only */ color: var(--color); /* blue */ } It’s been awhile since I had story time, so let’s me share the journey of a discontent css developer who finally stopped being so angry 😂

stackoverflow.com › questions › 73628095 › how-to-declare-variables-in-css

How to declare variables in css - Stack Overflow

When you use the variable without var you set the value to the variable

:root {
  --color: red; /* set a value "red" to the "color" variable */
}

If you want then to get a value from the variable, you need to use var:

.card {
  color: var(--color);  /* get a color from the "--color" variable */
}

From the MDN Docs:

Custom properties (sometimes referred to as CSS variables or cascading variables) are entities defined by CSS authors that contain specific values to be reused throughout a document. They are set using custom property notation (e.g., --main-color: black;) and are accessed using the var() function (e.g., color: var(--main-color);).

An example:

:root {
  --color: red; /* set default value for "color" variable */
}


#primary-cards {
  --color: #0F0; /* set custom value for "color" variable in primary cards */
}

.card {
  color: var(--color);  /* use the color variable */
}

<section id="primary-cards">
  <div class='card'>
    My card content
  </div>
</section>

<!DOCTYPE html>
<html>
<head>
<style>
  :root{
       /* --color: rbg)1,2,3,4);  error code, or --color variable doesn't exist */
      --blue: blue;
      
      --display-color: red;
      --NoFallBack-to-blue: blue;
      
      }
      
   .red{
      color: var(--display-color, var(--NoFallBack-to-blue))
      }
      
   .blue{
      color: var(--color, var(--blue))
      }
     
</style>
</head>
<body>

<div class="red">
  <p> color will not fallback to blue </p>
</div>


<div class="blue">
  <p> color will fallback to blue </p>
</div>


</body>
</html>

My bad, I didn't read the question, I only read the css code.

You can create a block of css root and assign a value to the declared variable.

For example:

:root {

   --color: rgb(53, 52, 52); 


  /* for fall back */
  --blue: #0000FF;
}

Inside a css selector, let's call the variable

.className{
   
    color: var(--color);
}

lets say --color doesn't exist or forgot to assign a value to the variable.

:root {

       --color: ; 
  
    
      /* for fall back */
      --blue: #0000FF;
    }

It is a fallback when first value doesn't work out then the program will fallback to next value which is --blue. The var(--blue) will display on the screen

.className{

    color: --var(--color, var(--blue))
}