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# Customization options

Customize Bootstrap 4 with our new built-in Sass variables for global style preferences for easy theming and component changes.

## 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 `<body>`, you’d do the following:

    $body-bg:    $gray-900;
    $body-color: $gray-600;

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
--- | --- | ---
`$spacer` | `1rem` (default), or any value > 0 | Specifies the default spacer value to programmatically generate our spacer utilities.
`$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 we already include.

Blue
Indigo
Purple
Pink
Red
Orange
Yellow
Green
Teal
Cyan

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

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

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

Color utility classes are also available for setting `color` and `background-color`.

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.

### 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.

Primary
Secondary
Success
Danger
Warning
Info
Light
Dark

### Grays

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

100
200
300
400
500
600
700
800
900

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

    $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;

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.