Learn the standard Windows and macOS shortcuts. Where the browser can capture the keys you press them for real; where the OS grabs them first you answer by clicking the on-screen keyboard.
A web page cannot see every key combination. Shortcuts the OS handles first never reach the browser. Press ⌘⇧3 and macOS really does take a screenshot; WinL really does lock the screen; CtrlW really does close this tab.
So every shortcut here is tagged as pressable or not. What you are learning is the combination, not the act of firing it, so clicking the keys teaches it just as well. When clicking, you do not hold the modifiers — click ⌘, then ⇧, then 3, and it judges as soon as you pick the non-modifier key.
1. The modifiers swap roles. Copy is ⌘C, but word-wise cursor movement is option+← (not Ctrl), and start/end of line is ⌘←/→ rather than Home/End.
2. The chords get longer. Paste-without-formatting is ⌘⌥⇧V — four keys. A screenshot to the clipboard is ⌃⌘⇧3 — also four. On macOS, adding ⌃ to a screenshot shortcut sends it to the clipboard instead of a file; knowing that one rule changes your whole workflow.
3. The same key means something else. The Delete key alone does not delete a file on macOS (you need ⌘Delete), and in Finder Return renames rather than opens.
Outside this page, both systems offer Sticky Keys, which lets you press modifiers one after another instead of together. Worth turning on if chords are hard for you.
Cheat sheets are everywhere, but reading one does not move your hands. This trains the standard Windows and macOS shortcuts by making you actually produce them, in four modes, with an honest split between the ones a browser can capture and the ones it cannot. A click-only route is built in from the start, because holding four modifiers is itself a barrier. No install, no account; records stay in your browser.
Windows is a trademark of Microsoft Corporation; macOS and Mac are trademarks of Apple Inc. This site is independent and not affiliated with either company.Shortcuts can change; please check each vendor’s official documentation for the latest.