Changing the appearance of the dashboard in all its pages, in addition to updating the code version to the latest version

I am looking for someone to help me change the appearance of the dashboard on all of its pages and upgrade the code version to the latest version. The coding language needed will be HTML, and I need to make design changes as part of the project. I also need the code to be optimized for mobile devices. If you have the skills and experience to deliver this project, I would love to hear from you!