---
layout: docs
title: Customization options
description: Customize Bootstrap 4 with our new built-in Sass variables for global style preferences for easy theming and component changes.
group: getting-started
toc: true
---

## Customizing variables

Every Sass variable in Bootstrap 4 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.

Variable overrides within the same Sass file can come before or after the default variables. However, when overriding across Sass files, your overrides must come before you import Bootstrap's Sass files.

Here's an example that changes the `background-color` and `color` for the `<body>` when importing and compiling Bootstrap via npm:

{% highlight scss %}
// Your variable overrides
$body-bg: #000;
$body-color: #111;

// Bootstrap and its default variables
@import "node_modules/bootstrap/scss/bootstrap";
{% endhighlight %}

Repeat as necessary for any variable in Bootstrap, including the global options below.

## Global options

Customize Bootstrap 4 with our built-in custom variables file and easily toggle global CSS preferences with new `$enable-*` Sass variables. Override a variable's value and recompile with `npm run test` as needed.

You can find and customize these variables for key global options in our `_variables.scss` file.

| Variable                    | Values                             | Description                                                                            |
| --------------------------- | ---------------------------------- | -------------------------------------------------------------------------------------- |
| `$spacer`                   | `1rem` (default), or any value > 0 | Specifies the default spacer value to programmatically generate our [spacer utilities]({{ site.baseurl }}/docs/{{ site.docs_version }}/utilities/spacing/). |
| `$enable-rounded`           | `true` (default) or `false`        | Enables predefined `border-radius` styles on various components.                       |
| `$enable-shadows`           | `true` or `false` (default)        | Enables predefined `box-shadow` styles on various components.                          |
| `$enable-gradients`         | `true` or `false` (default)        | Enables predefined gradients via `background-image` styles on various components.      |
| `$enable-transitions`       | `true` (default) or `false`        | Enables predefined `transition`s on various components.                                |
| `$enable-hover-media-query` | `true` or `false` (default)        | ...                                                                                    |
| `$enable-grid-classes`      | `true` (default) or `false`        | Enables the generation of CSS classes for the grid system (e.g., `.container`, `.row`, `.col-md-1`, etc.).     |
| `$enable-print-styles`      | `true` (default) or `false`        | Enables styles for optimizing printing.                                |

## Color

Many of Bootstrap's various components and utilities are built through a series of colors defined in a Sass map. This map can be looped over in Sass to quickly generate a series of rulesets.

### All colors

All colors available in Bootstrap 4, available as Sass variables and a Sass map in our `scss/_variables.scss` file. This will be expanded upon in subsequent minor releases to add additional shades, much like the [grayscale palette](#grays) we already include.

<div class="row">
  {% for color in site.data.colors %}
    {% unless color.name == "white" or color.name == "gray" or color.name == "gray-dark" %}
    <div class="col-md-4">
        <div class="p-3 mb-3 swatch-{{ color.name }}">{{ color.name | capitalize }}</div>
    </div>
    {% endunless %}
  {% endfor %}
</div>

Here's how you can use these in your Sass:

{% highlight scss %}
// With variable
.alpha { color: $purple; }

// From the Sass map with our `color()` function
.beta { color: color("purple"); }
{% endhighlight %}

[Color utility classes]({{ site.baseurl }}/docs/{{ site.docs_version }}/utilities/colors/) are also available for setting `color` and `background-color`.

{% callout info %}
In the future, we'll aim to provide Sass maps and variables for shades of each color as we've done with the grayscale colors below.
{% endcallout %}

### Theme colors

We use a subset of all colors to create a smaller color palette for generating color schemes, also available as Sass variables and a Sass map in our `scss/_variables.scss` file.

<div class="row">
  {% for color in site.data.theme-colors %}
    <div class="col-md-4">
      <div class="p-3 mb-3 swatch-{{ color.name }}">{{ color.name | capitalize }}</div>
    </div>
  {% endfor %}
</div>

### Grays

An expansive set of gray variables and a Sass map in `scss/_variables.scss` for consistent shades of gray across your project.

<div class="row mb-3">
  <div class="col-md-4">
    {% for color in site.data.grays %}
      <div class="p-3 swatch-{{ color.name }}">{{ color.name | capitalize }}</div>
    {% endfor %}
  </div>
</div>

Within `_variables.scss`, you'll find our color variables and Sass map. Here's an example of the `$colors` Sass map:

{% highlight scss %}
$colors: (
  red: $red,
  orange: $orange,
  yellow: $yellow,
  green: $green,
  teal: $teal,
  blue: $blue,
  pink: $pink,
  purple: $purple,
  white: $white,
  gray: $gray-600,
  gray-dark: $gray-900
) !default;
{% endhighlight %}

Add, remove, or modify values within the map to update how they're used in many other components. Unfortunately at this time, not _every_ component utilizes this Sass map. Future updates will strive to improve upon this. Until then, plan on making use of the `${color}` variables and this Sass map.
