Prompt

Make a heads or tails game. Make it a single HTML file that opens in a browser with nothing to install and no other files. Put the CSS and JavaScript inside it. Do not use image files or any external address; use emoji or letters if you need a symbol.

I call heads or tails, then a coin flips and shows the result. If I called it right, my streak goes up by one. If not, the streak goes back to zero.

Keep my best streak and show it next to the current one. Remember the best streak after the browser is closed and opened again.

Show the last ten results as a row of small marks so I can see the pattern.

Give the flip a moment of suspense rather than showing the answer instantly.

When you are done, check that a wrong call really resets the streak and that the best streak is never lowered.