The user wants me to create a single-page web app with a procedural L-system fractal tree that branches recursively and sways gently in the wind. They've specified that I should use the pre-provided p5.min.js library, which is already in the current directory. I need to create an index.html file that contains everything: CSS in a <style> tag, JS in a <script> tag, and it should be self-contained with no external resources or network requests.

Let me first check the current directory to see if p5.min.js exists.

Good, the p5.min.js file is present. Now I need to create an index.html file that contains:
- HTML structure
- p5.js library loaded via <script src="p5.min.js">
- CSS in a <style> tag
- JS in a <script> tag
- A procedural L-system fractal tree that branches recursively and sways gently in the wind

Let me create this single self-contained HTML file.

The website has been created! I've built an interactive L-system fractal tree using p5.js with:

1. A recursive L-system that grows over 4 generations using the classic "FF+[+F-F-F]-[-F+F+F]" rule
2. Wind animation that creates a gentle swaying effect using sine waves
3. A sky gradient background and grassy ground
4. Proper branch angles and dynamic adjustment for the wind

The tree is drawn recursively from the bottom center of the canvas, with each branch splitting into two at the appropriate angle. The wind effect is applied as a small angle perturbation that varies with time and position in the tree.

The file is completely self-contained with inline CSS and JavaScript, and only loads the pre-provided p5.min.js file from the local directory.