TITLE: Helix — The Double Helix Explained FILE: 052-dna-helix.html === PROMPT (exact prompt used) === Build "Helix — The Double Helix Explained", an educational, beautiful interactive visualization. Centre: a rotating B-DNA double helix drawn on canvas with 3D projection — two sugar-phosphate backbones as glossy ribbons (#2ec4b6 and #e71d36 with depth shading) and base pairs as rungs coloured by nucleotide (A #ff9f1c, T #ffbf69, G #6a4c93, C #8ac926), with correct pairing (A–T, G–C), ~10.5 base pairs per turn, and depth fading for the back strands. A clean biotech palette on off-white (#f7f9fb) with a dark-mode toggle. A side panel with annotations and leader lines (major/minor groove; hydrogen bonds: 2 for A–T, 3 for G–C; 5'→3' direction), a sequence input where typing A/T/G/C rebuilds the helix live (auto-generating the complementary strand), and an "Unzip" button that animates replication — the strands separate and new complementary nucleotides float in. Interaction: drag to rotate, scroll to zoom, hover a base pair to highlight and label it. Typography: a modern sans with a monospace sequence display. SHARED REQUIREMENTS (apply to every page in this 100-page collection): 1. One standalone HTML5 file. All CSS inline in