---
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, meaning you can override that default value in your own Sass even after that original variable's been defined. Copy and paste variables as needed, modify the values, remove the `!default` flag, and recompile.
For example, to change out the `background-color` and `color` for the ``, you'd do the following:
{% highlight scss %}
$body-bg: $gray-900;
$body-color: $gray-600;
{% endhighlight %}
Do the same for any variable you need to override, including the global options listed below.
## Global options
Customize Bootstrap 4 with our built-in custom variables file and easily toggle global CSS preferences with new `$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 |
| --------------------------- | ---------------------------------- | -------------------------------------------------------------------------------------- |
| `$spacer` | `1rem` (default), or any value > 0 | Specifies the default spacer value to programmatically generate our [spacer utilities](/utilities/spacing/). |
| `$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.
{% for color in site.data.colors %}
{% unless color.name == "white" or color.name == "gray" or color.name == "gray-dark" %}
{{ color.name | capitalize }}
{% endunless %}
{% endfor %}
Here's how you can use these in your Sass:
{% highlight scss %}
// With variable
.alpha { color: $purple; }
// From the Sass map with our `color()` function
.beta { color: color("purple"); }
{% endhighlight %}
[Color utility classes]({{ site.baseurl }}/docs/{{ site.docs_version }}/utilities/colors/) are also available for setting `color` and `background-color`.
{% callout info %}
In the future, we'll aim to provide Sass maps and variables for shades of each color as we've done with the grayscale colors below.
{% endcallout %}
### Theme colors
We use a subset of all colors to create a smaller color palette for generating color schemes, also available as Sass variables and a Sass map in our `scss/_variables.scss` file.
{% for color in site.data.theme-colors %}
{{ color.name | capitalize }}
{% endfor %}
### Grays
An expansive set of gray variables and a Sass map in `scss/_variables.scss` for consistent shades of gray across your project.
{% for color in site.data.grays %}
{{ color.name | capitalize }}
{% endfor %}
Within `_variables.scss`, you'll find our color variables and Sass map. Here's an example of the `$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.