--- layout: page title: Customize CSS --- New to Bootstrap 4, variable-based customization is a way for folks to quickly enable or disable global styles across all of Bootstrap's CSS. Simply update a variable's value and recompile using our Gruntfile. ## Available variables You can find and customize these variables in our `_variables.scss` file. | Variable | Values | Description | | --------------------------- | ---------------------------------- | ----------------------------------------------------------------------- | | `$spacer` | `1rem` (default), or any value > 0 | Specifies the default spacer value for our spacer utilities. | | `$enable-flex` | `true` or `false` (default) | Swaps `float` and `display: table` styles for `display: flex`. | | `$enable-rounded` | `true` (default) or `false` | Enables predefined `border-radius` styles on various components. | | `$enable-shadows` | `true` or `false` (default) | Enables predefined `box-shadow` styles on various components. | | `$enable-gradients` | `true` or `false` (default) | Enables predefined gradients via `background-image` various components. | | `$enable-transitions` | `true` (default) or `false` | Enables predefined `transition`s on various components. | | `$enable-hover-media-query` | `true` or `false` (default) | ... |