The user wants me to create an interactive force-directed graph using D3.js. Let me first check what's in the current directory to see the d3.min.js file and understand the context.

I need to:
1. Check what files exist in the current directory
2. Create a single HTML file with:
   - Inline CSS
   - Inline JavaScript
   - Load d3.min.js from the local directory
   - Create about 40 nodes in several clusters
   - Draggable nodes
   - Hover highlighting of neighbors
   - Zoom/pan functionality

Let me first check the directory.

Good, I can see d3.min.js is in the current directory. Now I'll create the index.html file with:
- A force-directed graph with ~40 nodes in several clusters
- Draggable nodes
- Hover highlighting of neighbors
- Zoom/pan functionality

I'll create the data inline (nodes and links) and implement all the interactivity.

I've created the index.html file with all the required features:

1. **Force-directed graph** with ~40 nodes (8 clusters × 5 nodes = 40 nodes)
2. **Draggable nodes** - implemented using d3.drag()
3. **Hover highlighting of neighbors** - builds an adjacency map and highlights the hovered node and all its connections while dimming others
4. **Zoom/pan** - implemented using d3.zoom()
5. **Inline data** - nodes and links are defined directly in the JavaScript

The graph features:
- 8 different clusters with distinct colors
- Links within clusters (more dense)
- Some cross-cluster links for connectivity
- Visual feedback on hover
- A legend showing the cluster names
- Controls panel explaining how to use the graph

Let me verify the file was created properly.

The file has been created. Let me also verify that the d3.min.js is being loaded correctly by checking if the file exists and has content.