Repeating Decimal Cycle Inspector

Goal Build a tiny offline tool that converts a fraction into a decimal while exposing where a repeating cycle begins and how long that cycle is. Deliverable Submit one self-contained HTML file with a descriptive .html filename, no larger than 26 KB. It must work locally without a server or internet connection. Requirements 1. Provide labelled numerator and denominator inputs starting at 1 and 7. Accept integer numerators from -999 through 999 and integer denominators from 1 through 250. 2. Update immediately to show the reduced fraction and its exact decimal form. Put a repeating block in parentheses, for example 1/6 = 0.1(6) and 1/7 = 0.(142857); show terminating decimals without parentheses. 3. Show the non-repeating prefix length, repeating-cycle length, and a compact remainder-trace table or list that makes the detected cycle verifiable. 4. Use sign handling and integer parts correctly, including -22/7 = -3.(142857), while avoiding negative zero. 5. Include visible reference checks for 1/3, 1/6, 1/7, 1/8, and -22/7 with their expected decimal forms. 6. For blank, fractional, nonnumeric, zero-denominator, or out-of-range input, show a specific inline message and remove stale results and trace data. 7. Use keyboard-operable native controls, visible focus, a polite live result announcement, strong contrast, and a layout usable from 360 to 1200 CSS pixels. Negative scope No floating-point approximation as the source of the displayed digits, arbitrary-precision library, denominator above 250, fraction quiz, random values, graphing, external assets, network requests, storage, clipboard access, tracking, accounts, or extra files. Pass/fail acceptance gates - One self-contained HTML file, 26 KB or smaller, that works offline with no external resources. - Exact results for all five visible checks plus 2/1 = 2 and 1/250 = 0.004. - Remainder-based cycle detection, reduced-fraction display, prefix and cycle lengths, and a readable trace are present. - Invalid inputs clear stale output and receive distinct useful messages; required accessibility signals are present. - No prohibited code, dependency, feature, or unsafe behavior. Scoring rubric (100 points, in order) 1. Decimal, reduction, sign, and cycle-detection correctness: 50 points. 2. Trace clarity and scope compliance: 20 points. 3. Invalid-state handling and accessibility: 20 points. 4. Visual polish and readable code: 10 points. Tie-breaker Prefer the submission whose remainder logic and boundary behavior are easiest to verify from readable code; then prefer the clearest trace. Visual styling is creatively open.