I used animation loop on the the 'Rounded' growing overlay of the navigation menu.
I used the 'hidden checkbox' approach to show or hide the menu box.
The 'hamburger menu', and the 'X' link is a label, pointing to the ID of the checkbox. So that, I could trigger the checkbox toggle while clicking on the other element.
I designed the animations of the 'hamburger menu' and the growing overlay.
This navigation menu is optimised for PC browser.