# Style guide
#### Font family
The main application uses the font-family: `proxima-nova, sans-serif`. **Only** when using this font for your (web) xApp to be embedded in XUMM, use this stylesheet:
```
```
When offering your application anywhere else than as embedded (web) xApp, check your licensing needs and requirements for the use of Proxima Nova.
#### Colours
Starting XUMM version 1.1 four colour palettes are available. The colour the app is running in will be passed to the xApp in the `style` parameter, see the [xapp/ott/:token](https://xumm.readme.io/reference/xappotttoken) documentation (applies to the SDK as well).
Used colour palette codes:
* LIGHT
* DARK
* MOONLIGHT
* ROYAL
{% hint style="info" %}
Your xApp launch URL will receive a GET parameter (query param) named `xAppStyle` containing the colour palette name as active on the client device. If your xApp URL is eg.:
```
https://my.app.local/some/app
```
... the URL opened will be:
```
https://my.app.local/some/app?xAppStyle={THEME}
```
{% endhint %}
#### Standard CSS stylesheets
The four available themes are shipped as Bootstrap (version 4.5) rolled stylesheets, ready to use. You can include a Bootstrap 4.5 stylesheet by pointing to:
```
https://xumm.app/assets/themes/xapp/xumm-{theme}/bootstrap.min.css
```
The `{theme}` element should be replaced by the theme name in **lower case** notation.
#### SPA / Front-end app only
To load the right stylesheet dynamically in an environment without a backend, consider using this script in your ``:
```html
```
#### Colours
