Force-directed graph · nemotron-3.5-super-vl

Let me start by checking if d3.min.js is present in the current directory.

d3.min.js is present. Let me write the index.html file with all the required behavior.

Now let me run the browser to verify. Let me use the browser tool to run index.html.

There's an error: "Cannot read properties of undefined (reading 'add')". This is in the neighbors Map setup. The issue is `neighbors.get(l.source)` where l.source is an object (not yet resolved by d3). In d3 forceLink, the link objects have source/target as references to node objects after the simulation initializes, but at data join time they may be the raw objects. Actually the issue is that links' source/target are the node objects themselves (from the links array we built with `source: start + k` which is a number ID, not an object). Wait, in our links array, source and target are numbers (IDs). So `neighbors.get(l.source)` where l.source is a number — that's fine, the Map keys are numbers. But the error is at `.add`. Let me check: `neighbors.set(d.id, new Set())` — d.id is a number. Then `neighbors.get(l.source)` — l.source is a number. That should work...

Wait, the error happens at the highlight function probably. Let me look: `neighbors.get(activeId)` where activeId is d.id (a number). That should be fine.

Actually the error "Cannot read properties of undefined (reading 'add')" — somewhere we call .add on undefined. Let me check the links setup. In the links array, source and target are numbers. But when we do `neighbors.get(l.source).add(l.target)` — if l.source is a number that's not a key... but all IDs 0-39 are keys. Hmm.

Wait, actually maybe the issue is the links array source/target being numbers vs the simulation forceLink needing objects. But the error is at setup time. Let me re-read: "Cannot read properties of undefined (reading 'add')". 

Actually wait — in the links data, I set `source: start + k` (a number) and `target: start + ((k+1)%10)` (a number). Then `neighbors.get(l.source)` — l.source is a number, key exists. `.add(l.target)` should work.

Hmm, but maybe the error is elsewhere. Let me think about the highlight function: `neigh.forEach(id => relevant.add(id));` — neigh is a Set, relevant is a Set, .add works. 

Actually, the issue might be that links in d3, when source/target are numbers, d3.forceLink with `.id(d => d.id)` will resolve them to node objects during simulation initialization. But at the time we build `neighbors`, the links still have numeric source/target. That's fine for the Map.

Wait, the error says "reading 'add'" — maybe `neighbors.get(l.source)` returns undefined because... no. Let me reconsider. Actually maybe the problem: in `node.each(function(d) {...})` and the link highlight, those are fine.

Let me look more carefully. Actually the error could be in the link data: when we create links with numeric source/target, and then d3.forceLink resolves them — but that's separate.

Actually, the real issue: I bet `neighbors.get(l.source)` — l.source is a number. But wait, did the Map get populated correctly? `nodes.forEach(d => neighbors.set(d.id, new Set()))`. d.id is number 0-39. So all keys exist.

Hmm, let me look at the actual error location. It just says "Cannot read properties of undefined (reading 'add')". Let me check the join — actually maybe the issue is that `links` data elements have source/target as numbers, but when highlight runs on mouseover, `l.source.id` — l.source is a number, so `l.source.id` is undefined! That's the bug.

In `link.each(function(l) {...})`, I do `relevant.has(l.source.id)` and `relevant.has(l.target.id)`. But l.source is a number (the ID), not an object. So `l.source.id` is undefined, and `relevant.has(undefined)` — that's fine, has doesn't throw. But wait, the error is about `.add`, not `.has`.

Let me reconsider. Actually the error appears on load ("error: Cannot read properties of undefined (reading 'add')"). This happens before any interaction. So it's during setup. The only `.add` calls during setup are in:
```
links.forEach(l => {
  neighbors.get(l.source).add(l.target);
  neighbors.get(l.target).add(l.source);
});
```
If `neighbors.get(l.source)` is undefined, then `.add` throws. This would happen if l.source is not a key in the Map. But all are 0-39...

Unless! d3.forceLink modifies the links array in place, converting source/target from numbers to node object references. This happens when `simulation.force("link", ...)` is created or when simulation starts. d3's forceLink, when initialized, if links have numeric source/target and `.id()` is set, it... actually no. d3-force's link force does NOT mutate the source/target of your link objects. It uses `.id()` to look up nodes.

Hmm wait, actually let me reconsider. d3-force link force: `link.initialize()` runs on start, and it does:
```
link = link.map(objectify);
```
where objectify converts {source, target} — if source is a number, it stays a number (objectify only wraps if it's not an object... actually let me recall). The link force's `initialize` does:
```js
function initialize() {
  i = 0;
  while (++i < n) ... 
  link.forEach(function(l) {
    if (typeof l.source !== "object") l.source = nodesById.get(l.source);
    ...
  });
}
```
Hmm, actually I'm not 100% sure d3-force mutates. But the error occurs on load before interaction. The simulation starts and ticked runs. But ticked doesn't call .add.

Wait — actually the error is logged once on load. Let me check: maybe d3-force DOES mutate the links array, converting numeric source/target to node objects. Then AFTER that, if something re-runs the neighbors building... no, neighbors is built once.

Let me reconsider: The error might be that `neighbors.get(l.source)` returns undefined because d3-force already mutated l.source into a node object, but neighbors was built before simulation start... no, neighbors built before simulation. 

Hold on — order in my code: neighbors is built after `links` array defined, before simulation. At that point l.source is a number. So neighbors.get(number) works. So no error there.

Then what calls .add on undefined? Let me search... `relevant.add(id)` — relevant is a Set, fine. `relevant.add(activeId)` — fine.

Hmm, actually maybe the issue is the links got mutated by forceLink to have object source/target, and then... no.

Wait, actually maybe d3-force link force mutates links converting source/target to objects, and this happens synchronously when? It happens on `simulation.start()` / `restart()`, which is called in dragstarted and initially. The simulation starts automatically on construction. So during first tick, link objects' source/target become node objects. But neighbors was already built.

I'm confused about the exact error. Let me just look at the screenshot — the graph renders (nodes 0-39 visible), so the basic structure works. The error might be non-fatal. But "Cannot read properties of undefined (reading 'add')" — 

OH WAIT. I see it now. In the links array, I create them with numeric source/target. But d3.forceLink with `.id(d => d.id)` — the link force, on initialize, looks up `nodesById.get(l.source.id)`? No. Let me recall d3-force link source:

```js
function index(d) {
  return d.index;
}
function find(nodeById, nodeId) {
  ...
}
function initialize() {
  ...
  link.forEach(function(l) {
    l.source = nodesById.get(l.source.id);  // ??? 
  });
}
```

Actually no. Let me recall the real d3-force link code:
```js
function forceLink(links) {
  let i = -1, n = links.length, node, id;
  ...
  function initialize() {
    i = 0;
    while (++i < n) {
      ...
    }
    link.forEach(function(l) {
      if (typeof l.source !== "object") l.source = link.find(l.source);  // no
    });
  }
}
```

I don't remember exactly. The point is, the error is likely that d3 mutates source/target to objects, but that happens after neighbors built. So that's not it either.

Let me just re-examine: maybe the error is `neighbors.get(l.source)` where l.source is a number but... actually all numbers 0-39 are keys. 

Hmm, unless the cluster ring links: `roots = [0,10,20,30]`, links between roots. Those are all valid keys.

I think the error might actually be harmless and occurs during highlight on some edge, but the console shows it once at load. Let me just check the screenshot — graph is rendered and interactive-looking. But the error could break highlight.

Actually, let me reconsider the highlight link code:
```js
link.each(function(l) {
  const el = d3.select(this);
  const connected = relevant.has(l.source.id) && relevant.has(l.target.id);
```
Here `l.source` is a number (our data), so `l.source.id` is `undefined`. `relevant.has(undefined)` returns false. So no links would be highlighted as "connected" — that's a bug but doesn't throw.

The throw ".add on undefined" — I really think it's `neighbors.get(l.source).add(...)` where get returns undefined. This means l.source is not a key. When would that be? If d3-force mutated l.source into a node object BEFORE neighbors was built. But neighbors is built before simulation...

Actually, the order: I build neighbors, THEN create simulation. The simulation constructor calls `initialize()`? Let me recall: `d3.forceSimulation(nodes)` — constructor just sets up. `.force(...)` adds forces. `.on(...)` adds listeners. `.start()` or `.restart()` begins. The simulation auto-restarts on construction? Actually `d3.forceSimulation` calls `restart()` internally? Let me recall — yes, the constructor calls `this.restart()`? No. Actually `d3.forceSimulation` constructor does NOT start automatically; it starts on first `.tick()` or via `restart()`. Hmm, but in newer d3, the simulation starts immediately via `restart()` in constructor? 

Actually, `d3.forceSimulation` constructor:
```js
function forceSimulation(nodes) {
  ...
  this.restart = restart;
  return restart();
}
```
Yes! The constructor calls `restart()` which calls `initialize()` on all forces. So the link force's initialize runs during construction, which may mutate link source/target to objects. But neighbors is built BEFORE `d3.forceSimulation(...)`, so at neighbors-build time, links still have numeric source/target. So neighbors building is fine.

So where's the error? Let me look at the order again in my code:
1. nodes, links defined
2. color scale
3. svg, g, link, node drawn
4. simulation created (this calls restart → link.initialize may mutate links source/target to objects)
5. neighbors Map built ← at this point, if forceLink mutated links, l.source is now a node OBJECT, not a number! Then `neighbors.get(l.source)` — looking up a node object in a Map keyed by numbers → undefined → `.add` throws!

That's the bug. The simulation constructor mutates the links' source/target to node object references before I build the neighbors Map.

Fix: Build the neighbors Map BEFORE creating the simulation, OR use the numeric IDs directly. Simplest: move the neighbors building before the simulation creation. Actually, better: build neighbors right after links are defined, before simulation. Let me reorder.

Actually even simpler — I should build neighbors before the simulation. Let me edit to move the neighbors block up, right after links array definition.

Also, I should fix the highlight link code to use numeric IDs directly: `l.source` and `l.target` are numbers in our data (even after forceLink mutation, they become objects... but if I build neighbors before simulation, then at highlight time, links may have been mutated to objects, so `l.source` is a node object with `.id`). Hmm, this gets confusing.

To be safe and consistent, let me make the links use node OBJECT references as source/target from the start (since forceLink resolves them anyway), OR just consistently treat them. 

Cleanest approach: After creating the simulation, the links will have source/target as node objects. But I want neighbor lookup by ID. Let me build neighbors using numeric IDs from a separate clean links structure.

Simplest robust fix: Build the neighbors Map from the original numeric data BEFORE creating the simulation. Then in highlight, for links, since after simulation they become objects, use `l.source.id` and `l.target.id`. But at highlight time (mouseover), links ARE objects (mutated). So `l.source.id` works then. And during neighbors build (before simulation), `l.source` is a number, `neighbors.get(number)` works. 

Wait but if I build neighbors before simulation, at that time l.source is a number → `neighbors.get(number)` → Set → `.add` works. Good. Then at highlight time, l.source is an object → `l.source.id` is the number → `relevant.has(number)` works. 

So the fix: move neighbors building before the simulation creation. Let me do that.

Also I realize there might be an issue with `l.source.id` — after forceLink mutation, l.source is the node object which has `.id`. Good.

Let me also double check: does forceLink actually mutate source/target to objects? In d3-force, the link force `initialize`:
```js
link.forEach(function(l) {
  if (typeof l.source !== "object") l.source = nodesById.get(l.source);
  if (typeof l.target !== "object") l.target = nodesById.get(l.target);
});
```
Hmm, actually I'm not certain it does this. Let me just be safe and move neighbors before simulation, and in highlight use `l.source.id`/`l.target.id` which works whether it's a number (no .id → undefined) or object. But if it's a number, `l.source.id` is undefined → `relevant.has(undefined)` false → links won't highlight. To handle both, I could normalize. 

Cleanest: make the links use object references from the start. Build nodes array first, then create links with `source: nodes[start+k]`, `target: nodes[...]`. Then forceLink won't mutate (they're already objects), and `l.source.id` works consistently, and `neighbors.get(l.source)` would be looking up an object in a number-keyed Map → undefined. That breaks neighbors.

OK the cleanest: keep links with numeric IDs. Build neighbors using numeric IDs (before or after simulation doesn't matter if I use the raw numbers). For highlight, access link source/target IDs robustly. Since after forceLink they might be objects with `.id`, and before they're numbers, I'll write a helper `nodeId(x) = (typeof x === "object" ? x.id : x)`.

Let me just rewrite cleanly: build neighbors before simulation using numeric IDs, and in highlight use a helper to get the id from source/target.

Let me edit the file: move neighbors block before simulation, and add a helper + use it in highlight link section.

Now remove the duplicate neighbors block later in the file and update the highlight link code to use nodeId helper.

Now update the link highlight code to use nodeId helper instead of l.source.id / l.target.id (since after simulation mutation they may be objects, but nodeId handles both). Actually they're objects after mutation so l.source.id works, but nodeId is safer. Let me update.

Now there's a subtle issue: in `highlight`, the node loop uses `d.id` which is a number, and `relevant` is a Set of numbers. Good. The link loop uses `nodeId(l.source)` which returns number. Good.

But wait, there's still a potential issue: the neighbors Map was built before simulation with numeric keys. In highlight, `neighbors.get(activeId)` where activeId is d.id (number) → works. Good.

Let me reload and check.

No console errors now. Let me verify the behaviors by interacting. Let me test dragging a node, panning, zooming, reset, and hover highlighting. Let me use the browser tools to click a node and check highlighting, drag a node, etc.

Let me first take a screenshot to see the state, then perform interactions. Let me drag a node - I'll use drag action from one node position to another.

Actually, let me think about what I can verify. Let me click on a node to test hover highlight. Let me click on node "0". Looking at the image, nodes are clustered in the center. Node 0 would be blue (cluster 0). Let me try to interact.

Let me do a series of checks:
1. Hover a node -> highlight it and neighbors
2. Drag a node -> connected links follow, camera stays
3. Pan background
4. Zoom
5. Reset view

Let me start with a click on a node. Let me try to click near the center-left where a node is. Hard to know exact coordinates. Let me just try clicking around.

Actually, let me do a drag test. Let me drag from a node to somewhere. But I need coordinates. Let me look at the image - nodes are around center (500, 400 area). Let me try clicking on a visible node.

Let me try a click at around (450, 400) which appears to be where nodes are.

The simulation settled and the graph spread out. The layout looks like the rings formed. Node 0,10,20,30 connect clusters. Let me verify the behavior: I need to test dragging a node, hover highlight, pan, zoom, and reset.

Let me try dragging a node and the reset. Let me do a drag operation to verify.

Drag works - node moved and links followed. Now let me test hover highlight, pan, zoom, and reset.

Zoom worked (graph got bigger). The "move" action failed validation — the tool only accepts specific actions: reload, inspect, screenshot, motion, click, drag, key, type, scroll. Let me use "motion" for hover instead. Let me test hover highlight with motion.

Pan worked (image 5 shows graph shifted to top-left after dragging from bottom-right to top-left). The motion frames (image 1-4) show the graph static — hovering didn't visibly highlight, but the motion screenshots may not capture the dimming clearly. Let me test the hover more carefully, and test reset view.

The reset view didn't bring the graph back into view — it's still off-screen. The issue is that `initialCamera` is captured on the first `simulationEnded`, but the reset transform computation might be wrong, OR the simulation keeps running and moves nodes after reset captured. Actually, the graph is off-screen because I panned it far away, and reset should bring it back. But it didn't.

The problem: `initialCamera` is set once on first `simulationEnded`. But after I dragged nodes and the simulation keeps running (alpha never fully 0 maybe), the positions changed. Also, the reset uses `initialCamera` from the very first settle — that should still be valid.

Wait, looking at the image: the graph is in the top-left corner partially. Actually after reset it might have transformed but the graph is still partially off-screen. Let me reconsider — the issue may be that the reset transition's computed transform isn't being applied correctly because `svg.property("__zoom")` or the zoom transform state is inconsistent.

Actually, looking more carefully, the reset DID transform but the graph ended up partially off-screen at top-left. This suggests the `initialCamera` bounding box isn't quite right, OR the graph nodes moved significantly after the initial settle (because I dragged a node and the simulation is still running with residual alpha).

The bigger concern: the reset should restore the *initial camera framing*. Since the simulation is still running and nodes keep moving, "initial framing" is a bit ambiguous, but the requirement is just to return to initial framing. The reset not working well is a problem.

Let me think about why reset failed. The graph appears at top-left corner, partially cut off. This means the transform scaled it small and positioned it top-left. 

Actually wait — maybe `initialCamera` wasn't captured because `simulationEnded` only fires when the simulation stops. With the forces I have (charge, center, x, y, link), the simulation may never fully stop, so `simulationEnded` never fires, so `initialCamera` is null, and the reset button's `if (!initialCamera) return;` does nothing!

That's the bug. The simulation runs continuously (forceManyBody keeps it jiggling), so `end` never fires, `initialCamera` stays null, and reset does nothing.

But the graph IS at top-left... hmm, that contradicts "reset does nothing". If reset did nothing, the graph would stay where I panned it (top area). Actually after panning, the graph was centered-ish. Let me re-examine: after the pan drag, image 5 showed the graph at top-left corner. Then I clicked reset, and it's still at top-left. So reset did nothing because `initialCamera` is null.

So I need a different approach to capture the initial framing. Options:
1. Capture initial camera right after the first tick render, before forces move things much.
2. Run the simulation a bit, then freeze positions as the "initial framing".

Better approach: Instead of relying on `end` (which may never fire), capture the initial bounding box after the simulation has run for some ticks, OR just compute it from the initial layout. But the initial layout (before simulation) is all at (0,0) since nodes start at x=0,y=0 by default. So I need to let the simulation run first.

Let me use a timeout: after ~2 seconds, capture the bounding box as initialCamera. Or capture it on the first few ticks once nodes have spread.

Actually a cleaner approach: capture initialCamera after the simulation has had time to settle somewhat. Let me set it via setTimeout after ~1500ms, reading current node positions.

But the graph keeps moving. The requirement says "Restore the initial camera framing without replacing the graph data." So capturing after a brief settle is reasonable.

Let me restructure: 
- Remove reliance on `end` for initialCamera.
- Use a one-time capture after a short delay (e.g., 1000ms) from current node positions.
- Also update the `simulation.on("end")` initial-fit to use this.

Let me also make reset work even if initialCamera is captured late. And I should make sure reset re-applies even after graph moves.

Let me rewrite the relevant section. I'll capture initialCamera via setTimeout.

Let me look at the current code structure for the initial camera / fit part.

Current:
```js
    let initialCamera = null;

    function ticked() { ... }

    function simulationEnded() {
      if (!initialCamera) { ... capture ... }
    }

    const simulation = d3.forceSimulation(nodes)
      ...
      .on("tick", ticked)
      .on("end", simulationEnded);
```

And:
```js
    // Initial zoom to fit
    simulation.on("end", () => {
      if (initialCamera && !window.__initialFitDone) { ... fit ... }
    });
```

I'll change to capture via setTimeout and trigger fit. Let me edit.

Actually, since the simulation may run indefinitely, I'll capture initialCamera after 1 second and do the initial fit then. Let me replace the simulationEnded-based capture with a setTimeout.

Let me edit the code.

The simulationEnded block isn't in the file anymore since I removed it? No wait, I kept simulationEnded earlier. Let me re-read the file to get exact text.

The order is: simulation defined first (with on("end", simulationEnded)), then `let initialCamera`, then ticked, then simulationEnded. But simulationEnded references initialCamera which is declared after... but that's fine since it's a function, called later. Let me read the simulationEnded function and the initial fit section.

Now let me read lines 140-150 to get the simulationEnded start.

Now I'll do a single edit replacing the block from `// Save initial positions for reset framing` through the `simulation.on("end", ...)` initial fit block with the new setTimeout-based approach. Let me construct the oldText carefully spanning from "// Save initial positions" to the end of the initial fit block.

Actually it's easier to do two edits. But the rule says merge nearby changes. Let me do one edit replacing the whole region from "// Save initial positions for reset framing" through the closing of the initial-fit `simulation.on("end"...)`.

The region:
```
// Save initial positions for reset framing
let initialCamera = null;

function ticked() {
  link
    .attr("x1", d => d.source.x)
    .attr("y1", d => d.source.y)
    .attr("x2", d => d.target.x)
    .attr("y2", d => d.target.y);

  node
    .attr("transform", d => `translate(${d.x},${d.y})`);
}

function simulationEnded() {
  // Capture initial framing after the layout has settled
  if (!initialCamera) {
    const xs = nodes.map(d => d.x);
    const ys = nodes.map(d => d.y);
    const minX = d3.min(xs), maxX = d3.max(xs);
    const minY = d3.min(ys), maxY = d3.max(ys);
    const pad = 60;
    initialCamera = {
      x0: minX - pad, y0: minY - pad,
      x1: maxX + pad, y1: maxY + pad
    };
  }
}

// ---- Zoom behavior ----
```
I want to keep ticked and zoom. Let me replace from `// Save initial positions` through `simulationEnded() {...}` closing `}` and the `simulation.on("end")` block.

Let me just replace the larger block from "// Save initial positions for reset framing" to the end of "Initial zoom to fit" block.

The issue is likely that the earlier edits changed whitespace, or the block isn't exactly as I think. Let me re-read the current state of the whole relevant region to build an exact match. Let me read from line 110 to 180.

Now I have the exact text. Let me replace from "// ---- Force simulation ----" through the end of the "Initial zoom to fit" block. Actually the `ticked` function is referenced by simulation before it's defined, but that's fine since simulation is created and ticked is hoisted? No, `function ticked()` is a function declaration, hoisted. Good.

Let me do the edit with exact oldText = the block from "// ---- Force simulation ----" to the end of the initial-fit block, and newText = my replacement.

I'll include the exact text. Let me write it carefully.

Now the `ticked` function is used by simulation before its definition in source order, but it's a function declaration so it's hoisted. Good. Now let me reload and test reset.

But wait — there's a subtlety. The initial fit via setTimeout at 900ms. But the page may not have rendered yet at 900ms? It should, DOM is ready. Let me reload and test.

Also I should verify hover highlight works. Let me reload and do a comprehensive test.

The initial fit didn't happen yet (900ms timeout hasn't fired since reload). Let me wait a moment and check. Let me reload and then interact. Actually the page just reloaded, so the 900ms timer is running. Let me test hover and then reset.

Let me test hover highlight first, then drag to pan away, then reset to confirm it returns to initial framing.

The `move` action isn't valid. Looking at the tool, valid actions are: reload, inspect, screenshot, motion, click, drag, key, type, scroll. The `motion` action is the one for mouse movement. Let me use `motion`.

The motion to (452, 402) — that's near node 0 (blue, center-left). The highlight should activate on node 0. Looking at the images, node 0 is highlighted (slightly larger circle) but I don't see obvious dimming of others... Actually it's hard to tell from the still frames whether dimming occurred. The CSS sets `.dimmed { opacity: 0.15 }` which should be visible. Let me test reset now and also verify dimming is more obvious.

Actually, the hover effect: node 0 gets `highlight` class (stroke-width 3px, stroke-opacity 1) and its neighbors stay normal, unrelated nodes get dimmed to 0.15. In the frames it's subtle. Let me proceed to test reset and drag again, which are the key required behaviors.

Let me pan first, then reset.

Pan works (graph moved to upper-left). Now click Reset view.

The reset didn't seem to return to the initial framing. The graph is still off-screen. The issue is that `initialCamera` was captured during the first page load (the first `reload`), but now the view is still panned away. Wait, actually the reset should restore to the camera framing captured at 900ms after page load. But the graph is still off-screen.

The problem: when the page first loaded and `captureInitialCamera` ran at 900ms, the nodes were at some positions. But the force simulation keeps running and moving nodes. So the "initial camera" captured at 900ms may not match what the user considers "initial framing." Also, after my pan, the reset should bring it back to the 900ms captured framing.

But looking at the screenshot, the graph is still off-screen after reset. That's odd. Let me think... 

Oh wait — I think the issue is that the initial fit already happened (window.__initialFitDone = true), so when I pan and click reset, the reset function runs `svg.transition().call(zoom.transform, ...)`. But maybe the transition got interrupted or the view is correct but the screenshot timing... Actually looking at the screenshot, the graph is clearly off-screen to the top right, similar to the pan result. So reset isn't working properly.

Actually, wait. Let me reconsider. The `captureInitialCamera` at 900ms captures the positions at that time. But the fit is applied at that time too (`fitToInitial` is called inside `captureInitialCamera`). Then the user pans. Then reset should re-apply the same transform.

But the reset isn't restoring. Hmm. Let me check — maybe `initialCamera` is null? No, it was captured. 

Actually, maybe the issue is the timing of this browser session. When I reload, a fresh page loads. The 900ms timer captures the initial camera. But then my subsequent actions happen on that same page instance. The `window.__initialFitDone` is set. 

Wait — but actually in THIS last sequence, I reloaded the page first (which re-ran everything fresh), then immediately did hover (move), then pan (drag), then reset (click). The 900ms timer would have captured the initial camera during the reload. So reset should work.

But the screenshot shows the graph is still off-screen. Let me look more carefully... Actually in the last screenshot, I see only a few blue nodes at top-left and an orange node at top-right. This looks like the graph is still panned off-screen, meaning reset didn't bring it back.

Hmm, but actually maybe the reset DID fire but the screenshot was taken before the 750ms transition completed? No, the click action should wait. Actually the tool might capture the screenshot immediately after the click, before the transition finishes. But 750ms transition... the tool probably waits a bit.

Let me reconsider. Actually maybe the problem is different. Let me look at the reset more carefully. The reset uses `svg.transition().duration(750).call(zoom.transform, ...)`. This should work.

Actually, wait. Let me re-examine. Maybe the issue is that `initialCamera` was captured at 900ms but by then the nodes hadn't spread out yet (they were still clustered), so the captured framing is tight around a small cluster, and when I look at "initial framing" it looks different. But that wouldn't cause the graph to be off-screen after reset.

Let me just re-test more carefully. Actually, the issue might be that the screenshot captured the state before the reset transition completed. Let me reload and do a cleaner test: wait for layout, then pan, then reset, and check.

Actually, I think the real issue might be more subtle. Let me reconsider the whole flow. When the page loads:
1. Simulation starts, nodes at center (all at width/2, height/2 initially since no x/y set)
2. Nodes spread out over time due to forces
3. At 900ms, `captureInitialCamera` captures the bounding box and fits the view

But actually, when nodes are first created, they don't have x/y set, so d3-force initializes them randomly. They start spread somewhat. By 900ms they've settled into a reasonable layout. The camera fits to that.

Then I pan away. Reset should bring it back to the 900ms framing. 

The screenshot after reset still shows off-screen graph. This is concerning. Let me reload and test reset more carefully, perhaps waiting longer for the transition.

Actually, I bet the issue is the screenshot timing. The tool takes a screenshot right after the click, and the 750ms CSS transition hasn't finished. Let me reload, pan, wait, reset, and check again. Or better, let me just reduce the transition duration to make it instant for reliability, or add a short wait.

Actually, let me just verify by reloading and doing a clean test sequence with a small delay. But I can't add delays between tool calls easily. Let me just reload and test reset immediately after the page settles (no pan first) to see if the initial fit works, then do pan+reset.

Actually, a cleaner approach: Let me make the reset instant (duration 0) to remove any transition timing issues, and verify. But the task says "Reset view to restore the initial camera framing" — a transition is fine but not required. Let me just verify it works.

Let me reload and do: wait for layout (the move action I did earlier effectively waited), then the state shows the fitted graph. Then I need to test reset after pan. The last test showed reset didn't visibly work, but it might be a transition timing issue with the screenshot.

Let me reload fresh and do pan then reset in a way that gives the transition time. Actually, I'll just trust it and also reduce the transition duration. Let me set duration to 400 or even 0 for the reset to be safe and instant.

Actually, I realize the real problem might be that `window.__initialFitDone` persists but `initialCamera` gets recaptured... no.

Let me just reload and test reset properly. I'll reload, wait via a move, then pan, then reset, then check with a screenshot. The key question is whether reset restores framing.

Let me also reconsider: maybe the reset IS working but the screenshot is captured mid-transition. Let me reload, pan, reset, and then do a separate inspect/screenshot to confirm the final state.

Let me reload first.

Let me make the reset more reliable. The issue might be that the transition duration of 750ms completes but the screenshot was taken immediately. Also, I want to make the reset robust. Let me improve the reset to be synchronous (no transition) so it's immediately visible, or keep transition but ensure it works.

Actually the issue may be that `svg.transition().call(zoom.transform, ...)` requires the zoom behavior to be bound which it is. Let me just make reset immediate and reliable. Let me change to use `svg.call(zoom.transform, ...)` directly without transition for reliability, or keep a short transition.

Let me rewrite the reset to be immediate and also ensure the graph recenters. Let me also verify by making it synchronous.

Wait, I removed the transition. But the task says "Reset view to restore the initial camera framing without replacing the graph data." Immediate reset is fine. Let me reload and test pan then reset.

Now let me do a clean pan → reset test. First pan the background, then reset.

The reset still isn't working. Let me debug. The issue might be that the `setTimeout(captureInitialCamera, 900)` hasn't completed before I reset, OR the reset coordinates are wrong. Let me check: after reload, the graph settles and at 900ms `captureInitialCamera` runs, computing initialCamera and fitting. Then I pan, then click reset.

But the click at (66, 127) - the Reset button is at top-left. Looking at the image, the button is at around y=127 which seems right. But after reset, the image still shows the panned state (nodes at top-left edge). 

Wait - maybe the issue is that `svg.call(zoom.transform, ...)` isn't actually updating the visual because the zoom transform needs to also be set on the svg's `__zoom` property. Let me check - `d3.zoom` when called via `svg.call(zoom.transform, ...)` should work.

Actually, looking more carefully: image 1 shows the pan result (nodes at left edge, button still visible at top-left). Image 2 shows... after reset... still showing nodes at left edge and button at top-left. So reset didn't change anything.

Hmm, maybe `initialCamera` is null at reset time because the 900ms timeout hasn't fired yet. But I reloaded, then immediately dragged - that's within 900ms, so initialCamera might be null, and reset returns early.

Let me add a check: the timeout is 900ms. The reload happens, then I drag immediately. The drag happens before 900ms, so initialCamera is null, reset does nothing. That's the bug!

I should either:
1. Wait longer before testing, or
2. Make the initial capture happen faster / synchronously-ish

But actually the real fix: I should make the reset work regardless, and ensure initialCamera is captured. Let me reduce the timeout or better, compute the initial camera synchronously right after creating the simulation but before it runs. Actually I can compute it right away since nodes are at (0,0) initially... no, they spread out over time.

Better approach: make the timeout shorter AND make reset robust. But the fundamental issue is timing. Let me just increase confidence by waiting for the 900ms to elapse. Actually, let me reconsider - maybe I should capture the bounding box at the time of reset if not yet captured, using current positions.

Let me make reset compute from current node positions if initialCamera is null. That's more robust. Actually simpler: just compute the fit at reset time from current nodes.

Let me rewrite reset to compute from current positions if needed. Actually, let me just keep it simple: in reset, if initialCamera is null, compute it from current positions. Let me update.

Actually, the cleanest fix: capture initial camera on first tick after a delay, but also make reset self-sufficient. Let me change reset to compute the framing from the nodes' current positions (which represent the "initial" settled-ish state). But that won't be "initial" if user moved nodes via drag... 

Hmm, the requirement: "Reset view to restore the initial camera framing without replacing the graph data." So it's about camera framing, not node positions. The initial framing is the framing when the graph first loads. So I should capture that once.

The problem is purely timing - I reset before 900ms. Let me just make the timeout much shorter, like 300ms, and also add a fallback in reset. Let me reduce to 400ms and add fallback computation in reset.

Now make reset self-sufficient: if initialCamera is null, compute from current node positions.

Wait, but if I call captureInitialCamera() in reset AFTER the user has panned/dragged, the node positions have changed, so the "initial" framing would be wrong. But this is just a fallback for the timing edge case. In normal operation, captureInitialCamera fires at 400ms via setTimeout, before any user interaction (usually). The fallback in reset is a safety net.

Actually, there's a subtle issue: if the user interacts before 400ms, then clicks reset, the fallback computes from moved positions. But that's an edge case and still reasonable behavior. Let me test now.

Let me reload and test: wait for graph to settle (the 400ms), then pan, then reset.

Now test: drag node, pan, wheel zoom, then reset.

The pan worked (image 1 shows the graph panned to upper-left). But reset (image 2) still shows the panned view — reset isn't returning to the center. The issue is the 400ms timer hasn't run yet when I test immediately after reload, so `initialCamera` is null, and `captureInitialCamera()` is called inside the click handler. But wait — the click handler calls `captureInitialCamera()` which reads `nodes` positions. At click time, the simulation has been running for however long, but positions may still be in the middle of the layout. The captured positions would be wherever the nodes currently are, not the "initial" centered framing.

Actually the real problem: after reload, I pan immediately (before 400ms capture), then reset. The reset calls captureInitialCamera() which reads current positions (already panned!), so it captures the panned framing as "initial" — making reset a no-op.

I need a better approach. The initial camera framing should be based on the node positions at the time of the FIRST render / capture, not current positions after user interaction. But if capture hasn't happened yet when user interacts, we're in trouble.

Better approach: capture initial camera framing from the initial node coordinates BEFORE the force simulation moves them. But the nodes start at random positions (d3 assigns random x/y on initialization). So I need to set initial x/y positions first, OR capture after the layout settles and treat THAT as the initial framing.

The cleanest solution: ensure `initialCamera` is captured reliably before any user interaction can break it. Since I can't control timing perfectly, let me capture the framing at a fixed point and ALSO make reset compute framing from the ORIGINAL positions.

Actually, the simplest robust fix: compute the initial framing from the node positions as they exist right after the layout has been running a bit (the 400ms capture). But to handle the race where user resets before capture, I should store the framing from the capture, and if capture hasn't happened, fall back to the current view but that's wrong.

Let me reconsider. The task says "Reset view to restore the initial camera framing without replacing the graph data." The "initial camera framing" is the framing when the graph is first shown. 

The best approach: set the initial node positions deterministically (e.g., in a grid/circle) BEFORE starting the simulation, so the layout starts from a known state, then capture the bounding box right away. But d3.forceSimulation randomizes positions on start unless we set them.

Alternative robust approach: Don't depend on a timer at all. Capture initialCamera based on node positions, but do it after forcing a few ticks, or just capture immediately after setting deterministic initial positions.

Let me set deterministic initial positions for nodes (spread them in the four clusters in rings), then compute initialCamera from those positions directly (no timer needed), then start the simulation. This makes reset reliable.

Actually, simplest: compute initialCamera from the nodes' initial x/y. But d3 forceSimulation sets random positions. Let me explicitly set each node's x, y to a deterministic arrangement before starting the simulation, then capture initialCamera from those.

Let me rewrite: place nodes in four cluster rings deterministically, set x/y, then compute initialCamera from those, then start simulation. This removes the timing race entirely.

Let me restructure the simulation setup.

Let me look at where nodes are created and set deterministic positions, then capture initialCamera immediately. Let me see the node creation section.

Let me set deterministic initial positions for nodes right after creating them, so I can compute initialCamera immediately without a timer race. I'll place each cluster in a ring at a corner of the canvas.

Let me edit the node creation to set x/y, and compute initialCamera right there. Then remove the timer-based capture.

Let me modify: after `const nodes = ...`, add deterministic x/y. Then after computing neighbors, compute initialCamera from the initial positions and fit. Remove the setTimeout.

Now compute initialCamera from these deterministic positions immediately and fit. Remove the timer and the capture-on-reset fallback (keep fallback but it's now fine since capture runs immediately). Let me update the simulation section.

Now the `ticked` function references `link` and `node` which are defined later in the file. That's fine because `ticked` is only called during simulation ticks, after link/node are defined. But the order in the file: ticked is defined before link/node? Let me check. Actually in the current file, ticked is now inside this new block which is before the link/node drawing. That's a problem — `link` and `node` won't be defined when ticked runs.

Wait, let me check the order. The new block I inserted is right after the neighbors section and before the SVG/zoom section. But `link` and `node` are defined after the SVG section. So `ticked` would reference undefined `link`/`node`.

I need to move the ticked function (and the fitToInitial/simulation) to AFTER link/node are defined. Let me check the current file order.

Actually, the original code had link/node defined, then simulation with ticked. I replaced the simulation section which was AFTER link/node. But my newText put ticked definition BEFORE link/node. Let me re-examine.

Looking at my edit: I replaced from "let initialCamera = null;" ... "setTimeout(captureInitialCamera, 400);". The original had: let initialCamera, function ticked, function simulationEnded, simulation, then setTimeout. The link/node were defined BEFORE all this (in the original, link/node come first, then "---- Force simulation ----").

Wait, in the original file order: nodes, links, color, neighbors, then SVG, link, node, then "---- Force simulation ----" with ticked/simulation. So ticked came AFTER link/node.

But my newText starts with the initialCamera block (which doesn't use link/node), then defines ticked (uses link/node), then simulation, then fitToInitial call. I placed this block where the old simulation block was — which is AFTER link/node. Let me verify by reading.

Actually, my oldText started with "let initialCamera = null;" which was right before "function ticked". In the original, that whole force-simulation block was AFTER link/node definitions. So my replacement is in the same location (after link/node). So ticked is still after link/node. Good.

But wait — did I accidentally move things? My newText doesn't include the link/node definitions. It's just replacing the force-simulation block. So link/node are still defined before this block. Good. ticked references link/node which are defined earlier. Fine.

However, `fitToInitial` uses `svg` which is defined in the SVG section before the force block. Good.

Now there's a subtlety: `initialCamera` is now a const computed at module level before simulation. The reset handler references initialCamera. Let me check the reset handler still works.

Let me check the reset handler section.

The reset handler should be later. Let me check the reset handler — it was in my newText? No, my newText ended with "fitToInitial();" before the "---- Zoom behavior ----". Wait, no. Let me re-read my newText. It ended with the fitToInitial() call and closing. But the original had the zoom behavior and reset handler AFTER the force block. Did my edit remove them?

My oldText ended at "setTimeout(captureInitialCamera, 400);" and the original had more after that (zoom behavior, reset handler, hover). My newText ended with "fitToInitial();" and a closing. So the zoom behavior and reset handler that were AFTER the oldText block are still there, just now following my new block. Let me verify the reset handler is intact.

The reset handler is missing! My newText ended before the reset handler. Let me check — my oldText in the edit included the reset handler? Let me re-check. My oldText was:

"let initialCamera = null; ... setTimeout(captureInitialCamera, 400);"

No, the oldText I used for the big edit was the force simulation block which ended at setTimeout. But wait, in an earlier edit I had already replaced the block that included reset handler. Let me re-examine.

Actually, the very first big edit (the one that succeeded) replaced from "---- Force simulation ----" through the reset handler and initial zoom block, with newText that ended at "---- Zoom behavior ----" ... no.

Let me just check where the reset handler is now. It's not in the range I just read (220-275). Let me search for it.

The reset handler is at line 171, but it still references `captureInitialCamera` which no longer exists (I removed that function). Let me read lines 171-185.

`captureInitialCamera` no longer exists. `initialCamera` is now a const that's always defined. Let me remove that fallback line.

Now there might be a duplicate fitToInitial definition. Let me check — I defined fitToInitial in the new block (line 138), but there might be an older one. Let me grep.

Good, only one fitToInitial and no captureInitialCamera or setTimeout. Now let me reload and test the full sequence.

The `ticked` function reference was moved. The `ticked` function was originally defined before the simulation, but I moved the simulation before `ticked`... wait, no. Let me check the order. The `ticked` function should be defined before the simulation uses it. Let me look at the file structure.

I replaced the block that had `let initialCamera`, `ticked`, `captureInitialCamera`, `fitToInitial`, then simulation. My new block has initialCamera, `fitToInitial`, then simulation. But I removed the `ticked` function definition! Let me check.

Looking at my newText: I have `initialCamera`, `fitToInitial`, then simulation. I did NOT include the `ticked` function. I need to add it back before the simulation.

Now there might be a duplicate `ticked` definition later. Let me check.

Good, only one definition each. Now let me reload and test.

The layout renders well with deterministic positions. But there's an error "Cannot access 'zoom' before initialization" because `fitToInitial()` is called before `zoom` is defined. Let me move the `zoom` definition before `fitToInitial`, or just reorder. Let me move `svg.call(zoom)` and the zoom def before the initial fit. Actually the error is at fitToInitial calling `svg.call(zoom.transform...)` but `zoom` const is defined later. Let me reorder: define zoom before fitToInitial call. Let me check the order.

I need to move the zoom definition before fitToInitial() call. Let me move the zoom block up before the force simulation/fitToInitial call.

Wait, `fitToInitial` uses `zoom` which is now defined before it's called (good). But `fitToInitial` is defined before `zoom` — that's fine since it's only called after. Let me reload.

The graph now loads with four deterministic rings and the cluster ring. Let me run the full verification: drag a node, pan, zoom, hover highlight, and reset.

The reset worked — image 2 shows the graph restored to the initial framing (four corner clusters visible, same as the post-reload state). Now let me test the drag-a-node behavior and hover highlight quickly to confirm everything works.

Actually, let me verify drag moves node with connected links following and camera stays put, plus hover highlight. Let me do a final quick check.

The graph is working. Let me do the full verification sequence in one clean pass: drag node, pan background, zoom, reset, hover highlight. I've already confirmed most. Let me confirm hover highlight works now with the deterministic layout.