I’m tasked with updating the appearance and structure of Universal Login templates, specifically altering the UI of input fields and buttons, rearranging elements within the auth:widget, and incorporating a header with a close button that redirects to my website upon clicking. How can I accomplish this level of customization using either the Management API or CLI? I aim to seamlessly integrate these modifications into the Universal Login experience while maintaining a smooth user flow. Any guidance or steps on achieving this would be greatly appreciated. Thank you!