CSS, Sass and Less

Visual Studio Code has built-in support for editing style sheets in CSS .css, Sass .scss and Less .less. This support includes:

IntelliSense

We have support for selectors, properties and values. Use kb(editor.action.triggerSuggest) to get a list of context specific options.

Proposals contain extensive documentation, including a list of browsers that support the property. To see the full description text of the selected entry, use kb(toggleSuggestionDetails).

Emmet snippets

Press kb(editor.emmet.action.expandAbbreviation) to expand the current abbreviation.

Tip: See the CSS section of the Emmet cheat sheet for valid abbreviations.

We also support User Defined Snippets.

Syntax coloring & Color preview

As you type, we provide syntax highlighting as well as in context preview of colors.

Syntax Verification & Linting

We support CSS version <= 2.1, Sass version <= 3.2 and Less version <= 1.7.

Note: You can disable VS Code's default CSS, Sass or Less validation by setting the corresponding .validate User or Workspace setting to false. json "css.validate": false

Goto symbol in file

Simply press kb(workbench.action.gotoSymbol).

Hovers

Hovering over a selector or property will provide an HTML snippet that is matched by the CSS rule.

Goto Declaration and Find References

This is supported for Sass and Less variables in the same file.

Note: Cross file references ('imports') are not resolved.

Transpiling Sass and Less into CSS

VS Code can integrate with Sass and Less transpilers through our integrated task runner. We can use this to transpile .scss or .less files into .css files. Let's walk through transpiling a simple Sass/Less file.

Step 1: Install a Sass or Less transpiler

For this walkthrough, let's use either the node-sass or less Node.js module.

Note: If you don't have Node.js and the NPM package manager already installed, you'll need to do so for this walkthrough. Install Node.js for your platform. The Node Package Manager (NPM) is included in the Node.js distribution. You'll need to open a new terminal (command prompt) for npm to be on your PATH.

npm install -g node-sass less

Step 2: Create a simple Sass or Less file

Open VS Code on an empty folder and create a styles.scss or styles.less file. Place the following code in that file:

$padding: 6px;

nav {
  ul {
    margin: 0;
    padding: $padding;
    list-style: none;
  }

  li { display: inline-block; }

  a {
    display: block;
    padding: $padding 12px;
    text-decoration: none;
  }
}

For the Less version of the above file, just change $padding to @padding.

Note: This is a very simple example, which is why the source code is almost identical between both file types. In more advanced scenarios, the syntaxes and constructs will be much different.

Step 3: Create tasks.json

The next step is to set up the task configuration. To do this open the Command Palette with kb(workbench.action.showCommands) and type in Configure Task Runner, press kbstyle(Enter) to select it. In the selection dialog that shows up, select Others.

This will create a sample tasks.json file in the workspace .vscode folder. The initial version of file has an example to run an arbitrary command. We will simply modify that configuration for transpiling Less/Sass instead:

// Sass configuration
{
    "version": "0.1.0",
    "command": "node-sass",
    "isShellCommand": true,
    "args": ["styles.scss", "styles.css"]
}

// Less configuration
{
    "version": "0.1.0",
    "command": "lessc",
    "isShellCommand": true,
    "args": ["styles.less", "styles.css"]
}

VS Code interprets node-sass or lessc as an external task runner exposing exactly one task: the transpiling of Sass/Less files into CSS files. The command we run is node-sass styles.scss styles.css or lessc styles.less styles.css.

Step 4: Run the Build Task

As this is the only task in the file, you can execute it by simply pressing kb(workbench.action.tasks.build) (Run Build Task). The sample Sass/Less file should not have any compile problems, so by running the task all that happens is a corresponding styles.css file is created.

Automating Sass/Less compilation

Let's take things a little further and automate Sass/Less compilation with VS Code. We can do so with the same task runner integration as before, but with a few modifications.

Step 1: Install Gulp and some plug-ins

We will use Gulp to create a task that will automate Sass/Less compilation. We will also use the gulp-sass plug-in to make things a little easier. The Less plug-in is gulp-less.

We need to install gulp locally (no -g switch):

npm install gulp gulp-sass gulp-less

Note: gulp-sass and gulp-less are Gulp plug-ins for the node-sass and lessc modules we were using before. There are many other Gulp Sass and Less plug-ins you can use, as well as plug-ins for Grunt.

Step 2: Create a simple Gulp task

Open VS Code on the same folder from before (contains styles.scss/styles.less and tasks.json under the .vscode folder), and create gulpfile.js at the root.

Place the following code in the gulpfile.js file:

// Sass configuration
var gulp = require('gulp');
var sass = require('gulp-sass');

gulp.task('sass', function() {
    gulp.src('*.scss')
        .pipe(sass())
        .pipe(gulp.dest(function(f) {
            return f.base;
        }))
});

gulp.task('default', ['sass'], function() {
    gulp.watch('*.scss', ['sass']);
})

// Less configuration
var gulp = require('gulp');
var less = require('gulp-less');

gulp.task('less', function() {
    gulp.src('*.less')
        .pipe(less())
        .pipe(gulp.dest(function(f) {
            return f.base;
        }))
});

gulp.task('default', ['less'], function() {
    gulp.watch('*.less', ['less']);
})

What is happening here?

1. Our default gulp task first runs the sass or less task once when it starts up.
2. It then watches for changes to any Sass/Less file at the root of our workspace, for example the current folder open in VS Code.
3. It takes the set of Sass/Less files that have changed and runs them through our respective compiler, for example gulp-sass, gulp-less.
4. We now have a set of CSS files, each named respectively after their original Sass/Less file. We then put these files in the same directory.

Step 3: Modify the configuration in tasks.json for watching

To complete the tasks integration with VS Code, we will need to modify the task configuration from before, to set a watch on the default Gulp task we just created. Your tasks configuration should now look like this:

{
    "version": "0.1.0",
    "command": "gulp",
    "isShellCommand": true,
    "tasks": [
        {
            "taskName": "default",
            "isBuildCommand": true,
            "showOutput": "always",
            "isWatching": true
        }
    ]
}

Step 4: Run the Build Task

Again, as this is the only task in the file you can execute it by simply pressing kb(workbench.action.tasks.build) (Run Build Task). But this time, we've set a watch so the Status Bar should indicate that on the left-hand side.

At this point, if you create and/or modify other Less/Sass files, you will see the respective CSS files generated and/or changes reflected on save. You can also enable Auto Save to make things even more streamlined.

If you want to stop the watch, you can press kb(workbench.action.tasks.build) again and click Terminate Running Task in the message box. Or you can use the Command Palette with kb(workbench.action.showCommands) and find the terminate command there.

Customizing CSS, Sass and Less Settings

You can configure the following lint warnings as User and Workspace Settings.

The validate setting allows you turn off the built-in validation. You would do this if you rather use a different linter.

Id	Description	Default
css.validate	Enables or disables all css validations	true
less.validate	Enables or disables all less validations	true
sass.validate	Enables or disables all sass validations	true

To configure an option for CSS, use css.lint. as the prefix to the id; for Sass and Less, use less.lint. and sass.lint..

Set a setting to warning or error if you want to enable lint checking, use ignore to disable it. Lint checks are performed as you type.

Id	Description	Default
validate	Enables or disables all validations	true
compatibleVendorPrefixes	When using a property with a vendor-specific prefix (for example -webkit-transition), make sure to also include all other vendor-specific properties eg. -moz-transition, -ms-transition and -o-transition	ignore
vendorPrefix	When using a property with a vendor-specific prefix for example -webkit-transition, make sure to also include the standard property if it exists eg. transition	warning
duplicateProperties	Warn about duplicate properties in the same ruleset	ignore
emptyRules	Warn about empty rulesets	warning
importStatement	Warn about using an import statement as import statements are loaded sequentially which has a negative impact on web page performance	ignore
boxModel	Do not use width or height when using padding or border	ignore
universalSelector	Warn when using the universal selector * as it is known to be slow and should be avoided	ignore
zeroUnits	Warn when having zero with a unit e.g. 0em as zero does not need a unit.	ignore
fontFaceProperties	Warn when using @font-face rule without defining a src and font-family property	warning
hexColorLength	Warn when using hex numbers that don't consist of three or six hex numbers	error
argumentsInColorFunction	Warn when an invalid number of parameters in color functions e.g. rgb	error
unknownProperties	Warn when using an unknown property	warning
ieHack	Warn when using an IE hack *propertyName or _propertyName	ignore
unknownVendorSpecificProperties	Warn when using an unknown vendor-specific property	ignore
propertyIgnoredDueToDisplay	Warn when using a property that is ignored due to the display. For example with display: inline, the width, height, margin-top, margin-bottom, and float properties have no effect.	warning
important	Warn when using !important as it is an indication that the specificity of the entire CSS has gotten out of control and needs to be refactored.	ignore
float	Warn when using float as floats lead to fragile CSS that is easy to break if one aspect of the layout changes.	ignore
idSelector	Warn when using selectors for an id #id as selectors should not contain IDs because these rules are too tightly coupled with the HTML.	ignore

Next Steps

Read on to find out about:

• Configure Tasks - Dig into Tasks to help you transpile your Sass and Less to CSS.
• Editing Evolved - Find out about the rich set of features the editor offers for languages such as CSS.
• HTML - CSS is just the start, HTML is also very well supported in VS Code.

Common Questions

Q: Do you provide a color selector?

A: No, this is currently not supported.

Q: Do you support the indentation based Sass syntax (.sass) ?

A: No, not yet.