You can add your own CSS to your `decker` project. This way you are able to customize the look of your slide decks even more. This assumes you have some knowledge about the workings of CSS.
## Example:
Simply add the following lines to your `YAML` slide deck header or the `decker.yaml` file in your project directory.
```
template:
css: dummy.css
```
In this example, the file `dummy.css` is on the same directory level as your `*-deck.md` file(s). If `dummy.css` contains the following content, the background of your slides should now be gray.
