Using the Pushy off-canvas menu from GitHub for my website has been great, but it's causing some trouble with my fixed header. When I scroll down the page, the header sticks perfectly to the top, but once I open the off-canvas menu, the header disappears. And when I close the menu, it abruptly comes back, which looks weird.
You can view the live demo of this issue on CodePen by following this link. You can also run the code snippet provided below directly.
I need help fixing this issue and making sure the header stays visible even when the off-canvas menu is opened. Any assistance would be greatly appreciated.
Thank you in advance.
/* JavaScript code goes here */
/* CSS styles go here */
<!-- HTML code goes here -->