ThemeMode

By default themeMode option will be set to user system settings ‘light’ or ‘dark’. But you can override it like this:
createAppKit({
  //...
  themeMode: "light",
});

themeVariables

By default themeVariables are undefined. You can set them like this:
createAppKit({
  //...
  themeVariables: {
    accent: "#00BB7F",
  },
});
The following list shows the theme variables you can override:
VariableDescriptionType
accentColor used for buttons, icons, labels, etc.string