Useful Periodic Table

- Dark mode improvements — Text in the periodic table is now properly visible in dark mode - Progress chart — Score history now tracks all tools (quiz, flashcards, puzzle, electron config, nomenclature, trends quiz) as separate colour-coded lines - 6 new chemistry tools - Stoichiometry Calculator - Periodic Trends chart - Solution Preparation calculator - Solubility Checker - Oxidation States calculator - Van der Waals real gas calculator - 3 new student views - Spectral Emission Lines — compare visible emission spectra of two elements side by side - Elemental Abundance — see how abundant each element is across the universe, Earth's crust, ocean, and the human body - Isotope Map — explore isotopes, stability, half-lives, and decay modes for every element