This piece of user script is to help user to print the question page with a neat layout.
It shows CodeForces difficulty if the problem comes from CodeForces.
After the menu item of Prepare to print is clicked, it removes all unnecessary elements and append a date to the top right corner of the page. So you will get a printer-friendly Luogu question page, which you can go directly to print it with your favorite browser.
After the menu item of Purge cache is clicked, it purges outdated difficulty values from cache.
