Utilize our source Sass files to take advantage of variables, maps, mixins, and more.
File structure#
Whenever possible, avoid modifying Bootstrap's core files. For Sass, that means creating your own stylesheet that imports Bootstrap so you can modify and extend it. Assuming you're using a package manager like npm, you'll have a file structure that looks like this:
your-project/
├── scss/
│ └── custom.scss
└── node_modules/
│ └── bootstrap/
│ ├── js/
│ └── scss/
└── index.html
If you've downloaded our source files and aren't using a package manager, you'll want to manually create something similar to that structure, keeping Bootstrap's source files separate from your own.
your-project/
├── scss/
│ └── custom.scss
├── bootstrap/
│ ├── js/
│ └── scss/
└── index.html
Importing#
In your custom.scss, you'll import Bootstrap's source Sass files. You have two
options: include all of Bootstrap, or pick the parts you need. We encourage the
latter, though be aware there are some requirements and dependencies across our
components. You also will need to include some JavaScript for our plugins.
// Custom.scss
// Option A: Include all of Bootstrap
// Include any default variable overrides here (though functions won't be available)
@import "../node_modules/bootstrap/scss/bootstrap";
// Then add additional custom code here
// Custom.scss
// Option B: Include parts of Bootstrap
// 1. Include functions first (so you can manipulate colors, SVGs, calc, etc)
@import "../node_modules/bootstrap/scss/functions";
// 2. Include any default variable overrides here
// 3. Include remainder of required Bootstrap stylesheets (including any separate color mode stylesheets)
@import "../node_modules/bootstrap/scss/variables";
@import "../node_modules/bootstrap/scss/variables-dark";
// 4. Include any default map overrides here
// 5. Include remainder of required parts
@import "../node_modules/bootstrap/scss/maps";
@import "../node_modules/bootstrap/scss/mixins";
@import "../node_modules/bootstrap/scss/root";
// 6. Optionally include any other parts as needed
@import "../node_modules/bootstrap/scss/utilities";
@import "../node_modules/bootstrap/scss/reboot";
@import "../node_modules/bootstrap/scss/type";
@import "../node_modules/bootstrap/scss/images";
@import "../node_modules/bootstrap/scss/containers";
@import "../node_modules/bootstrap/scss/grid";
@import "../node_modules/bootstrap/scss/helpers";
// 7. Optionally include utilities API last to generate classes based on the Sass map in `_utilities.scss`
@import "../node_modules/bootstrap/scss/utilities/api";
// 8. Add additional custom code here
With that setup in place, you can begin to modify any of the Sass variables and
maps in your custom.scss. You can also start to add parts of Bootstrap under
the // Optional section as needed. We suggest using the full import stack from
our bootstrap.scss file as your starting point.
Compiling#
In order to use your custom Sass code as CSS in the browser, you need a Sass compiler. Sass ships as a CLI package, but you can also compile it with other build tools like Gulp or Webpack, or with a GUI applications. Some IDEs also have Sass compilers built in or as downloadable extensions.
We like to use the CLI to compile our Sass, but you can use whichever method you prefer. From the command line, run the following:
# Install Sass globally
npm install -g sass
# Watch your custom Sass for changes and compile it to CSS
sass --watch ./scss/custom.scss ./css/custom.css
Learn more about your options at sass-lang.com/install and compiling with VS Code.
{ { < callout info }} Using Bootstrap with another build tool? Consider reading our guides for compiling with Webpack, Parcel, or Vite. We also have production-ready demos in our examples repository on GitHub. { { < /callout }}
Including#
Once your CSS is compiled, you can include it in your HTML files. Inside your
index.html you'll want to include your compiled CSS file. Be sure to update
the path to your compiled CSS file if you've changed it.
<!doctype html>
<html lang="pt-br">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Custom Bootstrap</title>
<link href="/css/custom.css" rel="stylesheet">
</head>
<body>
<h1>Hello, world!</h1>
</body>
</html>
Variable defaults#
Every Sass variable in Bootstrap includes the !default flag allowing you to
override the variable's default value in your own Sass without modifying
Bootstrap's source code. Copy and paste variables as needed, modify their
values, and remove the !default flag. If a variable has already been assigned,
then it won't be re-assigned by the default values in Bootstrap.
You will find the complete list of Bootstrap's variables in
scss/_variables.scss. Some variables are set to null, these variables don't
output the property unless they are overridden in your configuration.
Variable overrides must come after our functions are imported, but before the rest of the imports.
Here's an example that changes the background-color and color for the
<body> when importing and compiling Bootstrap via npm:
// Required
@import "../node_modules/bootstrap/scss/functions";
// Default variable overrides
$body-bg: #000;
$body-color: #111;
// Required
@import "../node_modules/bootstrap/scss/variables";
@import "../node_modules/bootstrap/scss/variables-dark";
@import "../node_modules/bootstrap/scss/maps";
@import "../node_modules/bootstrap/scss/mixins";
@import "../node_modules/bootstrap/scss/root";
// Optional Bootstrap components here
@import "../node_modules/bootstrap/scss/reboot";
@import "../node_modules/bootstrap/scss/type";
// etc
Repeat as necessary for any variable in Bootstrap, including the global options below.
Comece com o Bootstrap via npm com nosso projeto inicial! Vá para o repositório de modelos com exemplos com Sass e JS para ver como construir e personalizar o Bootstrap em seu projeto npm. Inclui compilador Sass, Autoprefixer, Stylelint, PurgeCSS e ícones Bootstrap.
Maps and loops#
Bootstrap includes a handful of Sass maps, key value pairs that make it easier
to generate families of related CSS. We use Sass maps for our colors, grid
breakpoints, and more. Just like Sass variables, all Sass maps include the
!default flag and can be overridden and extended.
Some of our Sass maps are merged into empty ones by default. This is done to allow easy expansion of a given Sass map, but comes at the cost of making removing items from a map slightly more difficult.
Modify map#
All variables in the $theme-colors map are defined as standalone variables. To
modify an existing color in our $theme-colors map, add the following to your
custom Sass file:
$primary: #0074d9;
$danger: #ff4136;
Later on, these variables are set in Bootstrap's $theme-colors map:
$theme-colors: (
"primary": $primary,
"danger": $danger
);
Add to map#
Add new colors to $theme-colors, or any other map, by creating a new Sass map
with your custom values and merging it with the original map. In this case,
we'll create a new $custom-colors map and merge it with $theme-colors.
// Create your own map
$custom-colors: (
"custom-color": #900
);
// Merge the maps
$theme-colors: map-merge($theme-colors, $custom-colors);
Remove from map#
To remove colors from $theme-colors, or any other map, use map-remove. Be
aware you must insert $theme-colors between our requirements just after its
definition in variables and before its usage in maps:
// Required
@import "../node_modules/bootstrap/scss/functions";
@import "../node_modules/bootstrap/scss/variables";
@import "../node_modules/bootstrap/scss/variables-dark";
$theme-colors: map-remove($theme-colors, "info", "light", "dark");
@import "../node_modules/bootstrap/scss/maps";
@import "../node_modules/bootstrap/scss/mixins";
@import "../node_modules/bootstrap/scss/root";
// Optional
@import "../node_modules/bootstrap/scss/reboot";
@import "../node_modules/bootstrap/scss/type";
// etc
Required keys#
Bootstrap assumes the presence of some specific keys within Sass maps as we used and extend these ourselves. As you customize the included maps, you may encounter errors where a specific Sass map's key is being used.
For example, we use the primary, success, and danger keys from
$theme-colors for links, buttons, and form states. Replacing the values of
these keys should present no issues, but removing them may cause Sass
compilation issues. In these instances, you'll need to modify the Sass code that
makes use of those values.
Functions#
Colors#
Next to the Sass maps we
have, theme colors can also be used as standalone variables, like $primary.
.custom-element {
color: $gray-100;
background-color: $dark;
}
You can lighten or darken colors with Bootstrap's tint-color() and
shade-color() functions. These functions will mix colors with black or white,
unlike Sass' native lighten() and darken() functions which will change the
lightness by a fixed amount, which often doesn't lead to the desired effect.
shift-color() combines these two functions by shading the color if the weight
is positive and tinting the color if the weight is negative.
{ { < scss-docs name="color-functions" file="scss/_functions.scss" }}
In practice, you'd call the function and pass in the color and weight parameters.
.custom-element {
color: tint-color($primary, 10%);
}
.custom-element-2 {
color: shade-color($danger, 30%);
}
.custom-element-3 {
color: shift-color($success, 40%);
background-color: shift-color($success, -60%);
}
Color contrast#
In order to meet the Web Content Accessibility Guidelines (WCAG) contrast requirements, authors must provide a minimum text color contrast of 4.5:1 and a minimum non-text color contrast of 3:1, with very few exceptions.
To help with this, we included the color-contrast function in Bootstrap. It
uses
the WCAG contrast ratio algorithm
for calculating contrast thresholds based
on relative luminance in
an sRGB color space to automatically return a light (#fff), dark (#212529)
or black (#000) contrast color based on the specified base color. This
function is especially useful for mixins or loops where you're generating
multiple classes.
For example, to generate color swatches from our $theme-colors map:
@each $color, $value in $theme-colors {
.swatch-#{$color} {
color: color-contrast($value);
}
}
It can also be used for one-off contrast needs:
.custom-element {
color: color-contrast(#000); // returns `color: #fff`
}
You can also specify a base color with our color map functions:
.custom-element {
color: color-contrast($dark); // returns `color: #fff`
}
Escape SVG#
We use the escape-svg function to escape the <, > and # characters for
SVG background images. When using the escape-svg function, data URIs must be
quoted.
Add and Subtract functions#
We use the add and subtract functions to wrap the CSS calc function. The
primary purpose of these functions is to avoid errors when a "unitless" 0
value is passed into a calc expression. Expressions like calc(10px - 0) will
return an error in all browsers, despite being mathematically correct.
Example where the calc is valid:
$border-radius: .25rem;
$border-width: 1px;
.element {
// Output calc(.25rem - 1px) is valid
border-radius: calc($border-radius - $border-width);
}
.element {
// Output the same calc(.25rem - 1px) as above
border-radius: subtract($border-radius, $border-width);
}
Example where the calc is invalid:
$border-radius: .25rem;
$border-width: 0;
.element {
// Output calc(.25rem - 0) is invalid
border-radius: calc($border-radius - $border-width);
}
.element {
// Output .25rem
border-radius: subtract($border-radius, $border-width);
}
Mixins#
Our scss/mixins/ directory has a ton of mixins that power parts of Bootstrap
and can also be used across your own project.
Color schemes#
A shorthand mixin for the prefers-color-scheme media query is available with
support for light and dark color schemes.
See the color modes documentation
for information on our color mode mixin.
{ { < scss-docs name="mixin-color-scheme" file="scss/mixins/_ color-scheme.scss" }}
.custom-element {
@include color-scheme(light) {
// Insert light mode styles here
}
@include color-scheme(dark) {
// Insert dark mode styles here
}
}