From M Hamza Siddiqui: New Styling Options for RecordDetail Screen Component

Nice add, Hamza!

Styling Options

You can apply SLDS classes to the MAIN BOX of this Screen Component.

The major classes for themes are: 
slds-box slds-theme_default
slds-box slds-theme_shade
slds-box slds-theme_shade slds-theme_alert-texture

More Details:

To use this, set the input attribute

The default values is “slds-box slds-theme_default”

But not limited to these classes but you can also add other classes like padding, margin, grid, alignment, visibility, and custom CSS classes as well (especially if you’re using this screen component in Lightning Flow within a community)

Install here