Web Messaging SDK: Customizing launcher position and theme via config JSON

Could someone explain the exact JSON structure required to override the default launcher position and color scheme in the Genesys Cloud Web Messaging deployment?

I am integrating the messaging widget into our internal dashboard. The documentation for the <script> tag configuration is sparse regarding visual customization. I need to move the launcher to the top-left and apply a custom primary color (#0056b3).

I attempted to pass a config object in the initialization, but the widget renders with default settings. Here is the snippet I am using:

GenesysCloudWebChat.init({
 deploymentId: 'my-deployment-id',
 region: 'eu',
 config: {
 launcher: {
 position: 'top-left',
 color: '#0056b3'
 }
 }
});

The console logs no errors, but the UI remains unchanged. Is this configuration supported via client-side injection, or does it require backend changes via the Deployment API? I suspect I am missing a specific key in the JSON payload. Any working examples would be appreciated.