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Bootstrap 4.3.1 dark theme that supports togging dark/light themes as well. There is no fluff, it changes the color of Bootstrap and that's it, no new thing to learn or unlearn, just Bootstrap, but Dark!
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Bootstrap 4 Dark theme

Bootstrap 4.3.1 dark theme that supports togging dark/light themes as well. There is no fluff, it changes the color of Bootstrap and that's it, no new thing to learn or unlearn, just Bootstrap, but Dark!

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Alpha - preview

Alpha - preview

This is a work in progress, if you like it and have some spare time, contributions are welcome.


SemVer is used to keep things easy for everyone.


Until the project reaches an official version 1.0.0, the pre-release -alpha.[build number] suffix is added to the version number.

Since this is only a dark version of Bootstrap, there should not be many breaking changes worth investing in versioning. So don't worry too much about compatibility, updating to the latest alpha release should be safe enough.

If this is a major concerns to you, feel free to say so, and I'll see what I can do about it.

How to use

Official builds are available in the public npm registry.

npm install @forevolve/bootstrap-dark --save

The package contains the content of the dist directory which includes the Bootstrap JavaScript files, for convenience, and the Bootstrap Dark CSS files. To load the dark theme, <link> the bootstrap-dark.css or the bootstrap-dark.min.css instead of the bootstrap[.min].css file.

Dark/Light toggle

You can now <link> both the toggle-bootstrap.css and the toggle-bootstrap-dark.css files to allow toggling the normal/dark theme based on your page body.

  • To display the original Bootstrap color, apply the bootstrap class on your body, like <body class="bootstrap">.
  • To display the Bootstrap Dark theme, apply the bootstrap-dark class on your body, like <body class="bootstrap-dark">.

CI builds

The CI builds are deployed to the following custom npm registry:

How to build

If you want to build the theme manually, modify it or even contribute, this section explains how.


  1. You need npm to build this project; see Node JS for more info.
  2. You need .NET Core 2; see .NET Core Downloads for more info.

Getting started

  1. Clone this repo
  2. Go to the app directory (cd app)
  3. Run npm install
  4. Run dotnet restore

Starting the project

  1. Run dotnet run (from the app directory) or if you are using VS Code, Start Debugging will work.
  2. Run npm run watch

Once you started both server and the watch command, the browser-sync proxy should open in a browser at the following URI: http://localhost:3002.

Other build info

There is a few npm and gulp scripts.

npm scripts

  1. gulp-watch simply runs gulp watch
  2. browser-sync-proxy starts browsersync watching for any wwwroot/css/*.css changes
  3. watch run both previous scripts in parallel

gulp scripts

  1. build-theme compile the theme to css.
  2. copy-dist-to-wwwroot copy the dist folder content to wwwroot (used by web pages).
  3. copy-bootstrap-js copy the bootstrap js files to the dist/js directory.
  4. watch execute copy-bootstrap-js then watch to rebuild the theme.
  5. default simply runs both build-theme and copy-bootstrap-js.

The project structure

  • app is the Asp.Net Core application that is used to test the theme. This directory is not packaged.
    • Pages are the Asp.Net Core Razor Pages. That's the preview.

      Why .NET Core? Well, I wanted to script some loops, and I know .Net; so I picked Razor Pages to do just that: dynamic pages! Moreover, it is open source and cross-platform.

      If you think that something else would be better, feel free to open an issue about it; I would not mind switching to another technology (see the Contribute section below).

    • Services are the web pages services; so far it's pretty thin.
    • wwwroot are the web assets; the dist files are copied there.
  • assets are the project assets (like the screenshot in the readme file).
  • dist are the redistributable files; if you want to copy/paste the files into your projects, that's the ones. They also include bootstrap JavaScript files, unaltered.
  • scss are the source theme files.
  • Other files (root): npm, license, readme, etc.


To contribute, start by opening an issue or reply on an existing issue so we can discuss your feature or bug to find the best way to approach it.

Once we settled on a strategy, you can then Fork/Code/Open a PR.

  • Please add yourself in the package.json contributors array.
  • Please keep PR focused on a single feature, it is easier for everyone this way and it helps keep the conversation focused. I way prefer multiple smaller PR than a single huge one.

Thanks in advance for your contribution.

See Contributing to ForEvolve open source projects and Contributor Covenant Code of Conduct for more information.

Release notes

Since CI build numbers are automated, it is hard to know for sure what the next deployed build number will be, so the (latest) version represent that version.


  • Update the project description, the "How to use" section, and add the "Release notes" section


  • Add support for dark/light toggling

1.0.0-alpha.774 & 1.0.0-alpha.723

  • Initial dark theme


More darkness!

The following project applies bootstrap-dark to the bootstrap documentation site allowing deeper testing of the theme:

Special thanks

I started this project based on the Bootstrap Theme Kit by Alexander Rechsteiner at Hacker Themes. This allows me to publish a lighter version of the theme; making it easier to be used (compared to the full Bootstrap Jekyll docs).

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