Build a single self-contained HTML file that renders an interactive fractal explorer (a Julia set or Mandelbrot set). Requirements: a smooth, colorful fractal rendered to a `<canvas>`; the ability to zoom in and out (mouse wheel or buttons) and pan around; a control that morphs the fractal in real time (e.g. a slider that changes the Julia constant `c`, or animates it continuously so the shape twists and evolves); a color-scheme/palette control; and an iteration-depth control that trades detail for speed. It should feel alive and mesmerizing to play with, and stay reasonably smooth. Make it look beautiful — rich color gradients, clean minimal UI. All CSS in a `<style>` tag and all JS in a `<script>` tag — no external libraries, images, or fonts. Return ONLY a single complete self-contained HTML file, no markdown fences, no explanation.
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