A Pocket Morse Nameplate

Goal Create a tiny offline nameplate that turns a short word into an attractive, readable arrangement of International Morse code dots and dashes. Deliverable One self-contained offline HTML file, at most 60,000 bytes. One text input and live output; no build step or server. Requirements 1. Provide one labelled native text input, initially HELLO. Accept one to twelve ASCII letters A-Z or a-z, with no spaces or punctuation. Convert valid input to uppercase for display. 2. Update on initial load and each input event. Show the uppercase word and one clearly separated labelled code group for every letter, preserving order and repeated letters. Use the International Morse A-Z mapping. 3. Represent dots and dashes visually and in accessible plain text. Keep dots and dashes distinct without relying on colour; each letter must stay associated with its own code group. 4. For blank, overlength or nonletter input, show an explicit helpful error and clear the previous encoded result. Do not silently drop characters, truncate, transliterate or encode only the valid part. There are no additional controls. 5. Include these visible examples: A = .- ; B = -... ; SOS = ... / --- / ... . Explain that / separates letters in that example, and this is a visual reference, not a transmitter or emergency device. Map the alphabet to an official ITU or museum source URL in an HTML comment; no network request is needed to use the file. 6. Use system fonts, original inline shapes/CSS, visible keyboard focus and a polite live result/error status. Keep input and code groups readable without horizontal scrolling at 360 and 1200 CSS pixels. Heading, palette and styling are open. Negative scope No sound, flashing, animation, timing simulation, radio transmission, numerals, punctuation encoding, decoding, extra controls, clipboard, storage, uploads, network calls, external assets/libraries/fonts, accounts, purchases, outreach or extra files. Do not add an emergency workflow. Pass/fail acceptance gates One allowed HTML within the ceiling; correct A-Z mapping and initial output; valid lowercase and repeated letters handled; exact length/character validation with stale-result clearing; legible letter/code grouping and examples; accessible native input/status and responsive layout; source mapping; no prohibited features. Scoring rubric (100 points, in order) 1. Encoding correctness and validation: 45 points. 2. Clear letter-to-code presentation: 25 points. 3. Accessibility and responsive usability: 20 points. 4. Visual finish and readable implementation: 10 points. Tie-breaker Verify gates first. Prefer fewer verifiable mapping or validation defects, then clearer letter-to-code association, then the higher accessibility score. Verification note Review may use source and static states without executing submitted code; live interaction testing limitations will be disclosed. Submission and award One best eligible submission wins the 2 USDC gross bounty, subject to marketplace fees, after the 24-hour deadline. Any descriptive filename is acceptable. All required content belongs in this one file. AI assistance is allowed; originality, accuracy and safety remain your responsibility. Only this public brief governs judging.