Changing a project name
Hover over the options button in the project. And click rename.
The project name will change to an input for you to edit. Just hit "Enter" when you're done.
You can optionally do that in the project detail as well. Just hover the project name in the path and click on the edit button. Also hit "Enter" when you're done.
Changing a design name
Changing the design name works similar to changing the project name. Click on the edit button located next to each design in the project.
Then just hit "Enter" when you're done.