The user wants me to build a side-scrolling platformer game using Phaser 3 (procedurally generated, no external assets). Let me create a complete `index.html` file that:

1. Loads `phaser.min.js` from the local directory
2. Uses ONLY procedurally generated graphics (no external images/audio)
3. Implements:
   - Side-scrolling camera
   - Player run and jump
   - Scrolling platforms
   - Enemies to stomp
   - Coins to collect
   - A goal flag
   - Classic Mario-style mechanics

Let me first check what's in the workspace directory.

Good, `phaser.min.js` is present. Now let me build the complete game. This will be a substantial single-file HTML game with:

- Procedural graphics via Phaser's Graphics API (generate textures at boot)
- Tilemap-like level built from overlapping static sprites
- Player physics with gravity, run, jump, double-jump
- Enemy AI (simple back-and-forth patrol)
- Stomp mechanics (jump on enemy head to kill)
- Coin collection
- Scrolling camera that follows the player
- A flag at the end
- Score display and lives
- Game states (title, playing, game over, win)

Let me write this comprehensively.

The file is written. Let me verify it's correct and works properly by checking a few things. Let me also test to make sure the Phaser integration is good and review the file for any issues.

Let me re-read the file to check for potential bugs in level generation - particularly the staircase building function which I noticed has some redundant/confusing logic.

I need to fix the staircase function which has confusing/duplicate code. Let me also verify the rest of the file and rewrite it cleanly. The main issues are:

1. The `buildStairs` function has confusion with the stair logic
2. The stair section calls reference `groundY` which is a local variable
3. The `buildStairs2` is dead code that should be removed
4. Need to clean up the level data builder

Let me rewrite the index.html file clean, fixing all these issues.

The file is written. Let me verify it's complete and correct by checking the end of the file and doing a quick sanity check.

The file looks good. Let me verify the structure by checking key sections:
1. The phaser.min.js script tag is present
2. Boot scene creates all textures
3. Game scene has all the game mechanics
4. The level is generated procedurally

Let me also check for any obvious issues by searching for common problems.

Good. Let me verify the overall structure and check for any issues.

The file is well-structured. Let me also verify there are no syntax issues by checking balanced braces and quoting.

The file is clean and complete. Let me do a final check of the game's key features to make sure everything is covered:

1. ✅ Side-scrolling platformer
2. ✅ Procedurally generated graphics (ground, brick, coins, player, enemies, flag, clouds, bushes, platforms, spikes)
3. ✅ Player run (arrow keys or A/D) and jump (up arrow, space, or W)
4. ✅ Scrolling platforms (physics static groups)
5. ✅ Enemies that patrol back and forth
6. ✅ Stomp enemies from above
7. ✅ Collect coins (scattered across the level)
8. ✅ Question blocks with coins
9. ✅ Goal flag at the end
10. ✅ Procedural sound effects via Web Audio API
11. ✅ Lives system
12. ✅ Score system
13. ✅ Camera follows player
14. ✅ Pits/obstacles (spikes, gaps in ground)
15. ✅ Staircase sections
16. ✅ Pipes as decoration
17. ✅ No external assets - all procedural

The file is complete and self-contained. It's present at /workspace/index.html with phaser.min.js already in the same directory.