Every Sass variable in Bootstrap 4 includes the `!default` flag, meaning you can override that default value in your own Sass. Copy and paste variables as needed, modify the 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. This means that your modified Sass variables should be called before you import Bootstrap Sass files. For example, to change out the `background-color` and `color` for the `<body>`, you'd do the following::
Customize Bootstrap 4 with our built-in custom variables file and easily toggle global CSS preferences with new `$enable-*` Sass variables. Override a variable's value and recompile with `npm run test` as needed.
| `$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/). |
| `$enable-grid-classes` | `true` (default) or `false` | Enables the generation of CSS classes for the grid system (e.g., `.container`, `.row`, `.col-md-1`, etc.). |
Many of Bootstrap's various components and utilities are built through a series of colors defined in a Sass map. This map can be looped over in Sass to quickly generate a series of rulesets.
### All colors
All colors available in Bootstrap 4, available as Sass variables and a Sass map in our `scss/_variables.scss` file. This will be expanded upon in subsequent minor releases to add additional shades, much like the [grayscale palette](#grays) we already include.
[Color utility classes]({{ site.baseurl }}/docs/{{ site.docs_version }}/utilities/colors/) are also available for setting `color` and `background-color`.
We use a subset of all colors to create a smaller color palette for generating color schemes, also available as Sass variables and a Sass map in our `scss/_variables.scss` file.
Add, remove, or modify values within the map to update how they're used in many other components. Unfortunately at this time, not _every_ component utilizes this Sass map. Future updates will strive to improve upon this. Until then, plan on making use of the `${color}` variables and this Sass map.