Hi Abdullah,
To rotate the globe, you’ll need to do something like this example for your smaller widget. CSS animations will not work.
For the background, you’ve already removed the skybox, so you should be able to use CSS and HTML to get the result you want.
For the logo, you are allowed to remove the Cesium logo, but make sure none of your other data or imagery requires attribution. This can be done by calling CreditDisplay.destroy
Thanks,
Gabby