What banks a day
Finishing the run once — reaching the end of the countdown — banks today, whatever your hit rate turned out to be. This is a streak for showing up, not a leaderboard for skill; your score is recorded for your own record and for the scorecard, but it doesn't gate the calendar dot. Come back and the page shows your banked result instead of the start screen. Want another go at the same pattern? Practice runs are always available and never touch the streak.
Streaks and missed days
The streak counts consecutive banked days ending today or yesterday. Bank today and it keeps climbing. Skip a day entirely and the count resets to zero the next time you visit — the calendar strip keeps every day you ever banked, so the history survives even when the streak doesn't. All of it lives in this browser's storage; there's no account to log into and nothing to lose sync with.