How to namespace Twitter Bootstrap so styles don't conflict

Question

I want to use Twitter Bootstrap, but only on specific elements, so I need to figure out a way to prefix all Twitter Bootstrap classes with my prefix, or use the less mixins. I'm not experienced with this yet so I don't quite understand how to do this. Here's an example of the HTML that I'm trying to style:

<div class="normal-styles">
  <h1>dont style this with bootstrap</h1>
  <div class="bootstrap-styles">
    <h1>use bootstrap</h1>
  </div>
</div>

In this example, Twitter Bootstrap would normal style both h1s, but I want to be more selective about which areas I apply the Twitter Bootstrap styles.

Answer 1

This turned out to be easier than I thought. Both Less and Sass support namespacing (using the same syntax even). When you include bootstrap, you can do so within a selector to namespace it:

.bootstrap-styles {
  @import 'bootstrap';
}

Update: For newer versions of LESS, here's how to do it:

.bootstrap-styles {
  @import (less) url("bootstrap.css");
}

A similar question was answered here.

Answer 2

@Andrew great answer. You'll also want to note that bootstrap modifies the body {}, mainly to add font. So when you namespace it via LESS/SASS your output css file looks like this: (in bootstrap 3)

.bootstrap-styles body {
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
    font-size: 14px;
    line-height: 1.428571429;
    color: #333333;
    background-color: white;
}

but obviously there will not be a body tag inside your div, so your bootstrap content will not have the bootstrap font (since all bootstrap inherits font from parent)

To fix, the answer should be:

.bootstrap-styles {
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
    font-size: 14px;
    line-height: 1.428571429;
    color: #333333;
    background-color: white;

    @import 'bootstrap';
}

Answer 3

Putting @Andrew, @Kevin and @adamj's answers together (plus a few other styles), if you include the following in a file named "bootstrap-namespaced.less", you can simply import 'bootstrap-namespaced.less' into any less file:

// bootstrap-namespaced.less

// This less file is intended to be imported from other less files. 
// Example usage:
// my-custom-namespace {
//  import 'bootstrap-namespaced.less';
// }

// Import bootstrap.css (but treat it as a less file) to avoid problems 
// with the way Bootstrap is using the parent operator (&).
@import (less) 'bootstrap.css';

// Manually include styles using selectors that will not work when namespaced.

@import 'variables.less';

& {
    // From normalize.less

    // Previously inside "html {"
    // font-family: sans-serif; // Overridden below
    -ms-text-size-adjust: 100%;
    -webkit-text-size-adjust: 100%;

    // Previously inside "body {"
    margin: 0;

    // From scaffolding.less

    // Previously inside "html {"
    // font-size: 10px; // Overridden below
    -webkit-tap-highlight-color: rgba(0,0,0,0);

    // Previously inside "body {"
    font-family: @font-family-base;
    font-size: @font-size-base;
    line-height: @line-height-base;
    color: @text-color;
    background-color: @body-bg;
}

Answer 4

Adding a namespace to bootstrap CSS will break modal functionality as the bootstrap adds a 'modal-backdrop' class directly to the body. A workaround is to move this element after opening the modal, e.g.:

$('#myModal').modal();
var modalHolder = $('<div class="your-namespace"></div>');
$('body').append(modalHolder);
$('.modal-backdrop').first().appendTo(modalHolder); 

You can remove the element in a handler for the 'hide.bs.modal' event.

Answer 5

First clone bootstrap from github:

git clone https://github.com/twbs/bootstrap.git

Install requirements:

npm install

Open scss/bootstrap.scss and add your namespace:

.your-namespace {
    @import "functions";
    ...
    @import "utilities/api";
}

Compile bootstrap:

npm run dist

Open dist/css/bootstrap.css and remove the namespace from the html and body tag.

Afterwards copy the content of the dist folder into your project and you're all set.

Have fun!

Answer 6

Use the .less version of the files. Determine which less files you require, then wrap those .less files with:

.bootstrap-styles {

    h1 { }

}

This will give you the output of:

.bootstrap-styles h1 { }

Answer 7

I did a GIST with Bootstrap 3 all inside a class named .bootstrap-wrapper https://gist.github.com/onigetoc/20c4c3933cabd8672e3e

I started with this tool: http://www.css-prefix.com/ And fix the rest with search and replace in PHPstorm. All fonts @font-face are hosted on maxcdn.

First line example

.bootstrap-wrapper {font-family:sans-serif;-ms-text-size-adjust:100%;-webkit-text-size-adjust:100%}

Answer 8

Namespacing breaks the Modal plugin's backdrop div, since that is always added directly to the <body> tag, bypassing your namespacing element which has the styles applied to it.

You can fix this by changing the plugin's reference to $body before it shows the backdrop:

myDialog.modal({
    show: false
});

myDialog.data("bs.modal").$body = $(myNamespacingElement);

myDialog.modal("show");

The $body property decides where the backdrop will be added.

Answer 9

To explain better all the steps what Andrew was talking about for those who don't know what Less is. Here is a link that explain pretty well how it is done step by step How to isolate Bootstrap or other CSS libraries

Answer 10

Preconditions

• You didn't setup a CSS preprocessor.

  → Otherwise try this: https://stackoverflow.com/a/13977230/2911452

• Your Bootstrap version is older than 4.1.

  → Otherwise try this: https://stackoverflow.com/a/49910653/2911452

• You're unlikely to update your Bootstrap version. This solution is only practical for legacy parts of your website/application.

• You can self-host css

Solution

Prefix all css selectors with a class selector:

1. Copy all the CSS from the CDN into your editor (e.g. http://netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css)

2. Wrap the whole thing with a selector (SCSS style), for example .bootstrap-styles:

.bootstrap-styles{
  html{font-family:sans-serif;-ms-text-size-adjust:100%;-webkit-text-size-adjust:100%}body{margin:0}article,aside /* etc... */
}

3. Use a tool to convert SCSS to CSS. I used https://jsonformatter.org/scss-to-css . (See screenshot at the end)

4. Self-host the resulting CSS file and include it on the pages where you need it

5. Wrap the parts that require Bootstrap styling with <div class="bootstrap-styles"> ... </div>

   → Bootstrap styles will only be applied to these parts

6. You can optionally minimize the resulting CSS.

Caveats

• Resulting .bootstrap-styles html { selector will obviously not work, as the html tag won't have a parent. You could fix this by changing it into just .bootstrap-styles {. Same applies to body.

• Icons and fonts with a relative path will be broken. You can find these by searching for url(.

  • Option 1. Remove these styles if you don't need them
  • Option 2. Update the URls to use am absolute path to the CDN (e.g. https://netdna.bootstrapcdn.com/bootstrap/3.1.1/fonts/glyphicons-halflings-regular.svg#glyphicons_halflingsregular
  • Option 3. Download the assets from the CDN and self-host these as well.

• You can't use a dependency management tool like npm. You'll have to go through these steps everytime you want to update Bootstrap (see precondition).

Screenshot

Converting SCSS to CSS

Answer 11

Most simple solution - start to use custom build isolated css classes for Bootstrap.

For example, for Bootstrap 4.1 download files from css4.1 directory -

https://github.com/cryptoapi/Isolate-Bootstrap-4.1-CSS-Themes

and wrap your HTML in a div with the class bootstrapiso :

<div class="bootstrapiso">
<!-- Any HTML here will be styled with Bootstrap CSS -->
</div>

Page template with isolated bootstrap 4 will be

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="description" content="">
    <title>Page1</title>

    <!-- Isolated Bootstrap4 CSS - -->
    <link rel="stylesheet" href="css4.1/bootstrapcustom.min.css" crossorigin="anonymous">   

    <!-- JS -->
    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" crossorigin="anonymous"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js" crossorigin="anonymous"></script>
    <script defer src="https://use.fontawesome.com/releases/v5.0.9/js/all.js" crossorigin="anonymous"></script>

  </head>

  <body>

  <div class="bootstrapiso">
  <!-- Any HTML here will be styled with Bootstrap CSS -->
  </div>

  </body>
</html>

Answer 12

As a further note for everyone. To get modals working with a backdrop you can simply copy these styles from bootstrap3

.modal-backdrop {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 1040;
  background-color: #000;
}
.modal-backdrop.fade {
  filter: alpha(opacity=0);
  opacity: 0;
}
.modal-backdrop.in {
  filter: alpha(opacity=50);
  opacity: .5;
}

Answer 13

I faced the same issue and method proposed by @Andrew unfortunately didn't help in my specific case. Bootstrap classes collided with classes from another framework. This is how this project has been incepted https://github.com/sneas/bootstrap-sass-namespace. Feel free to use.