How it works:
Start on input page: 3 fields — Power (W), Hours/day, Cost/kWh

Use keyboard to type digits and decimal point.
Press Enter to confirm a field or move to next.
After last input, results page opens showing:
Daily and monthly consumption (kWh),

Monthly cost.
On results screen, click anywhere on Back to Input button to return.

Pressing ESC cancels input or exits app if on input page with empty buffer.