reactjs – How to override the color of the title of the toolpad-mui

I am new to UI development and trying to use react/ui/javascript. I am developing a dashboard and using the MUI Toolpad.

The default color that the MUI Toolpad takes is the primary color but I want to override with some other color. I checked the theming option but I am not clear how to specify the cssVariables that overrides the default color.
I am using a custom theme in a json file and applying that theme, but it is not overriding the color. –

"typography": {
    "fontFamily": "\"Droid Sans\", \"Helvetica\", \"Arial\", sans-serif",
    "allVariants": {
      "color": "#212121"
    }
},

Could anyone please provide an example.