fix leaderboard initials entry readability with improved contrast and light background

add leaderboard persistent storage and fix styling

clean: remove perfect rounds metric and update leaderboard styling

fix level progression and leaderboard accessibility

simplify game mechanics and consolidate to single AI model

fix ui issues: larger chat icons and proper book contextualization

Add sticky control panel for mobile-friendly navigation

fix: improve UI consistency and prevent capitalized words as blanks

fix: add spaced underscores and mobile dropdown for questions

fix: clean up AI response processing and improve UI

revert: restore working contextualization by reverting to 77c4776 while preserving font improvements

fix: reduce welcome overlay text size and spacing to prevent cutoff

improve: enhance welcome overlay styling and timing

feat: add welcome overlay CSS styles to main stylesheet

feat: minimal deployment with essential JavaScript modules and complete CSS