Caps Lock
Each task shows code as it is now and the result you need. Edit it with Vim commands right in the browser. When you finish, Klava compares your keystrokes with the shortest solution and shows it, so you learn the efficient way, not just a way.
Motions h j k l w b e 0 ^ $ gg G, find f t F T, inserts i a I A o O, edits x r s D C J, operators d c y with motions and text objects like iw, i", i( and i{, line commands dd cc yy, paste p P, counts and undo u.
Switch to the regular editor mode to practise VS Code-style shortcuts: word jumps, selection, deleting and moving lines and toggling comments. Or try find-and-fix drills where you spot the bug yourself.