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 the included Gruntfile as needed.
Bootstrap 4 ships with a `_custom.scss` file for easy variable overrides. Copy and paste relevant lines from `_variables.scss` into the custom file and recompile your Sass to change our default values. **Be sure to remove the `!default` flag from override values.**
For example, to change out the `background-color` and `color` for the `<body>`, you'd do the following:
{% highlight scss %}
// Bootstrap overrides
//
// Copy variables from `_variables.scss` to this file to override default values
// without modifying source files.
$body-bg: $gray-dark;
$body-color: $gray-light;
{% endhighlight %}
Do the same for any variable you need to override, including the global options listed below.
## Global options
You can find and customize these variables for key global options in our `_variables.scss` file.
| `$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.). |
