Build Tally

Make the first screen of a counting app called Tally. The whole screen is one giant tap target: tapping anywhere adds one to the count, and the count shows as a very large number in the middle of the screen, big enough to read at arm's length while my hands are busy — and it must still fit on screen when someone has turned their phone's text size all the way up. Under the number, in small text, the word [what you are counting — one word, e.g. "laps"]. At the bottom, one button that subtracts one, labelled with a minus sign and the words "One less": an outlined button spanning the width of the screen, quiet enough that it never competes with the number. It does nothing, and doesn't buzz, when the count is already zero. Every tap gives a light buzz so I can count without looking. Keep every word that appears on the screen together in its own file, separate from the screen's layout and behaviour, so I can reword the app without touching the design.

Done means: I open the app on my phone, tap the middle ten times and see 10 with a buzz each time, press the subtract button twice and see 8, pressing subtract at zero leaves it at zero and does not buzz, and with my phone's text size turned all the way up the whole number still fits on screen.

Two changes. First, the count must survive: if I close the app completely and open it again tomorrow, the number is exactly where I left it. Second, add a way to start over: a small "Reset" in the top corner that asks me first, in a panel that slides up from the bottom, saying exactly what I am about to lose in the app's own words — for example "Reset the count? 47 [your word] will be cleared." — with a clear way to cancel. When it's exactly one, it should read [your word for just one] instead of the plural. Resetting gives a firmer buzz than a normal tap, so I feel that something bigger happened. Don't change how the counting screen already behaves — I've checked it and I don't want it touched.

Done means: I count to 5, force-close the app, reopen it and still see 5; I press Reset, see the panel naming 5 in my own word, cancel, and still have 5; I press Reset again, confirm, and see 0 with a firmer buzz than a count.

Add a goal. At the top of the screen there's a thin bar that fills from left to right as the count climbs toward a target I set, with the target shown as small text like "8 of 20". Tapping that area lets me type a new target, and it won't accept anything that isn't a whole number above zero. The moment the count reaches the target, the big number gives one quick bounce, a soft bloom of the accent colour spreads behind it, the bar turns the accent colour, the small text becomes "Goal reached", and the phone gives a success buzz — once. Not again on later taps, and not again when I reopen the app on a goal I already finished. But if I drop back below the target and climb to it again, do celebrate again — that's a fresh arrival, not a repeat. If I haven't set a target, the bar is hidden completely — no empty bar sitting there, no "0 of 0" — and the only sign of the feature is a quiet "Set a goal" where those numbers would be, so I can always find my way in. Don't change how the counting, the memory, or the reset behave — they're checked and working, and I want them left alone.

Done means: With no target there is no bar at all and the top corner just reads "Set a goal"; I set a target of 3, tap three times, and on the third tap the number bounces once, the bar fills and turns colour, the text reads "Goal reached", and I feel the success buzz; a fourth tap adds to the count with no second celebration; and closing and reopening the app keeps the target without celebrating again.