Custom version

You can customize your version of Spectre.css by editing Sass files in /src directory or removing unneeded components from .scss source files.

Sass Source Code

If you are looking for Less version of Spectre.css, please switch to Less branch.

Less Branch

Compiling CSS

Spectre uses Gulp for compiling CSS. Firstly you need to install NPM, which is used to manage Gulp and other dependencies.

Then, you can build the CSS file from the command line:

  1. Navigate to the root directory of Spectre.
  2. Run npm install. NPM will install all dev dependencies as listed in package.json.
  3. When completed, run gulp build task to compile Sass to CSS and minify files.
  4. You can find compiled CSS files in /dist directory.

All available Gulp tasks:

  • gulp build - compile Sass to CSS and minify files (default)
  • gulp docs - compile Docs related files
  • gulp watch - watch file changes and re-compile CSS files

Importing Sass

It is recommended to customize Spectre by importing Sass source files to your projects. In this way, you can keep Spectre up to date without conflicts, since Spectre code and your custom code are separate.

  • First, create your own project and install Spectre via NPM or other package managers.
  • Then create your project-name.scss file in the root folder. You can use project-name.scss to define your variables.
  • Compile the Sass file to CSS to get the custom version of Spectre.
// Example of project-name.scss
// Define variables to override default ones
$primary-color: #2e5bec;
$dark-color: #3e396b;

// Import full Spectre source code
@import "node_modules/spectre.css/src/spectre";

Alternatively, you can create custom _variables.scss and import it to project-name.scss.

// Example of project-name.scss
@import "variables";

// Import only the needed components
@import "node_modules/spectre.css/src/buttons";
@import "node_modules/spectre.css/src/forms";

Folder structure

├── dist/                           // Build folder
│   ├── spectre-exp.css
│   ├── spectre-exp.min.css
│   ├── spectre-icons.css
│   ├── spectre-icons.min.css
│   ├── spectre.css
│   └── spectre.min.css
├── docs/
│   ├── dist/                       // Pre-built CSS folder
│   │   ├── spectre-exp.css
│   │   ├── spectre-exp.min.css
│   │   ├── spectre-icons.css
│   │   ├── spectre-icons.min.css
│   │   ├── spectre.css
│   │   └── spectre.min.css
|   ├── css/                        // Docs CSS files
│   │   └── docs.css
|   ├── src/
│   │   ├── scss                    // Docs Sass files
│   │   │   └── docs.scss
│   │   ├── index.pug               // Docs Pug files
│   │   └── ...
│   ├── examples/                   // Example tempalte
│   │   └── starter.html
│   ├── ../
│   ├── index.html
│   └── ...
├── src/                            // Source Sass files
│   ├── spectre.scss
│   ├── spectre-icons.scss
│   ├── spectre-exp.scss
│   ├── _mixins.scss
│   ├── _variables.scss
│   └── ...
├── gulpfile.js
├── package.json
└── ...


Spectre.css is designed with consistent design language. You can use your own variables to create your new or match existing design. All variables in _variables.scss include !default flag. You can redefine the variables to override the values.

Variables - Colors

Gray dark
Gray light

Variables - Button mixins

There are 2 button variant mixins in _mixins.scss to generate different color variants.

  • @mixin button-variant($color: $primary-color);
  • @mixin button-outline-variant($color: $primary-color);
<!-- filled button with the success color -->
.btn-success {
  @include button-variant($success-color);

<!-- outlined button with the success color -->
.btn-outline-success {
  @include button-outline-variant($success-color);

Variables - Sizes

The default REM (root em) size in Spectre.css is 20px.

Please note in the Chinese/Japanese/Korean version, Chrome uses 12px as default minimum font size. That is why Spectre sets rem default html font size to 20px, which is relatively easy to calculate.

Spectre uses 4px as the unit size. Sizes of components are based on the unit size.

Variables - Custom prefix

There is also a way to add custom prefix to all CSS classes. You can use gulp-css-prefix plugin and add a new Gulp task to enable it.

npm install gulp-css-prefix

To add spectre- to all classes, you can add the Gulp task to gulpfile.js file.

var cssPrefix = require('gulp-css-prefix');

gulp.task('prefix', function() {

After you compile your version of Spectre in the /dist, run gulp prefix in the directory of Spectre.