diff --git a/js/appearance/index.js b/js/appearance/index.js
index 72f98be..bd88838 100644
--- a/js/appearance/index.js
+++ b/js/appearance/index.js
@@ -2,6 +2,7 @@ import { app } from "/scripts/app.js";
 import {
   DEFAULT_SCHEME,
   NODE_COLOR_SCHEMES,
+  collectGraphNodes,
   schemeColors,
   shouldRecolor,
   titleInk,
@@ -30,10 +31,9 @@ function applyScheme(node, colors) {
 }
 
 function repaintAll(nextScheme, previousScheme) {
-  const nodes = app.graph?._nodes || app.graph?.nodes || [];
   const next = schemeColors(nextScheme);
   const previous = schemeColors(previousScheme);
-  for (const node of nodes) {
+  for (const node of collectGraphNodes(app.graph)) {
     if (!isAusbossNode(node)) continue;
     if (!shouldRecolor(node, previous)) continue;
     applyScheme(node, next);
diff --git a/js/shared/appearance.mjs b/js/shared/appearance.mjs
index 12c5035..9019a8d 100644
--- a/js/shared/appearance.mjs
+++ b/js/shared/appearance.mjs
@@ -36,6 +36,22 @@ export function titleInk(hex) {
   return luminance > 0.6 ? "#1a1a1a" : "#ffffff";
 }
 
+// Flatten every node reachable from a graph, descending into subgraph
+// containers via `node.subgraph`. Accepts a graph exposing `_nodes` or
+// `nodes`, or a plain node array; the visited set breaks reference cycles.
+export function collectGraphNodes(graph, visited = new Set()) {
+  if (!graph || visited.has(graph)) return [];
+  visited.add(graph);
+  const nodes = Array.isArray(graph) ? graph : graph._nodes || graph.nodes || [];
+  const collected = [];
+  for (const node of nodes) {
+    if (!node) continue;
+    collected.push(node);
+    if (node.subgraph) collected.push(...collectGraphNodes(node.subgraph, visited));
+  }
+  return collected;
+}
+
 // A node is repainted only while it is still "following the setting": either
 // it carries no colors while the previous scheme was the theme default, or it
 // still wears exactly the previous scheme's pair. Anything else — a color the
diff --git a/tests/appearance.test.mjs b/tests/appearance.test.mjs
index 8cab22b..4d7e454 100644
--- a/tests/appearance.test.mjs
+++ b/tests/appearance.test.mjs
@@ -4,6 +4,7 @@ import assert from "node:assert/strict";
 import {
   DEFAULT_SCHEME,
   NODE_COLOR_SCHEMES,
+  collectGraphNodes,
   schemeColors,
   shouldRecolor,
   titleInk,
@@ -78,3 +79,30 @@ test("titleInk falls back to light ink on malformed input", () => {
   assert.equal(titleInk("e0e0e0"), "#ffffff");
   assert.equal(titleInk("#zzzzzz"), "#ffffff");
 });
+
+test("collectGraphNodes flattens nested subgraphs", () => {
+  const inner = { _nodes: [{ id: 3 }] };
+  const graph = { _nodes: [{ id: 1 }, { id: 2, subgraph: inner }] };
+  assert.deepEqual(
+    collectGraphNodes(graph).map((node) => node.id),
+    [1, 2, 3],
+  );
+});
+
+test("collectGraphNodes accepts nodes arrays and plain arrays", () => {
+  const viaNodes = { nodes: [{ id: 1 }] };
+  assert.deepEqual(collectGraphNodes(viaNodes).map((node) => node.id), [1]);
+  const plain = [{ id: 1 }, { id: 2, subgraph: [{ id: 3 }] }];
+  assert.deepEqual(collectGraphNodes(plain).map((node) => node.id), [1, 2, 3]);
+  assert.deepEqual(collectGraphNodes(null), []);
+  assert.deepEqual(collectGraphNodes({}), []);
+});
+
+test("collectGraphNodes survives subgraph reference cycles", () => {
+  const graph = { _nodes: [{ id: 1 }] };
+  graph._nodes.push({ id: 2, subgraph: graph });
+  assert.deepEqual(
+    collectGraphNodes(graph).map((node) => node.id),
+    [1, 2],
+  );
+});