The lockscreen is based on Andrew Ambrosino's iOS 7 inspired look for OS X 11. It has the same font, and starry wallpaper found in iOS 7 as well.
Customize it ! Choose between many option like
● Clock & clock size
● Wallpaper and wallpaper animation
● Text color between black and white
● Customize "Press key to unlock" string
The installation procedure is as follows:
1) Just drag and drop the screensaver into 'Screen Savers alias' folder in the dmg
2) This will install it on your computer
3) Then go to system preferences and select the new screensaver
4) You can customize more options in the preferences
You can grab the screensaver as a free download from Bodysouldspirit's website below.