# Theming
By default KVision includes the standard [Bootstrap](https://getbootstrap.com/) look and feel. It's modern, elegant and proven in many production environments. Just include `kvision-bootstrap` module in your `build.gradle.kts` file. But there are other possibilities as well.
## Adding a custom CSS file to your application
You can add a custom CSS file to define your own CSS classes, which can be used throughout your code (almost every component supports the `className: String?` constructor parameter and the `addCssClass(css: String)` and `removeCssClass(css: String)` methods). Of course you can also overwrite and change the standard Bootstrap classes.
You can add as many CSS files as you wish. Just save your `*.css` files in `src/main/resources/css` directory and `require` them in your main `App` object.
{% code title="App.kt" %}
```kotlin
class App : Application() {
init {
require("css/kvapp.css")
require("css/other.css")
}
override fun start() {
// ...
}
}
```
{% endcode %}
## Replacing Bootstrap CSS with a custom one
You can remove `BootstrapCssModule` initializer from your application and include different CSS file in the main `index.html` of your application. It can be loaded from any local or remote source.
{% code title="index.html" %}
```markup
KVision App
```
{% endcode %}
You can create such a file manually or [build your own Bootstrap](https://getbootstrap.com/docs/5.1/customize/overview/) version from sources. To include a local version of Bootstrap, simply place `mybootstrap.min.css` in the `src/main/web/css` directory.
## Using free themes from [Bootswatch](https://bootswatch.com/)
There are some great free themes ready to use available at [JSDelivr](https://www.jsdelivr.com/package/npm/bootswatch). For instance to use Materia (material-like) theme make the following change to your `index.html`.
{% code title="index.html" %}
```markup
KVision Address Book
```
{% endcode %}
## Using KVision without Bootstrap
KVision can also be used with no Bootstrap at all. Just exclude all \*bootstrap\* modules from your `build.gradle.kts` file. You won't be able to use components from these modules, which depend on Bootstrap's JavaScript and styling. But you can use any other CSS framework (see examples for [Fomantic UI](https://github.com/rjaros/kvision-examples/tree/master/fomantic) and [Patternfly](https://github.com/rjaros/kvision-examples/tree/master/patternfly)).