diff --git a/scripts/build-dist.mjs b/scripts/build-dist.mjs
index b30f1167..02a633f0 100644
--- a/scripts/build-dist.mjs
+++ b/scripts/build-dist.mjs
@@ -38,8 +38,20 @@ function copyFile(src, dest) {
   if (fs.existsSync(src)) {
     fs.copyFileSync(src, dest);
   } else {
-    console.error(`Error: Source file ${src} does not exist.`);
-    process.exit(1);
+    const message = `Error: Source file ${src} does not exist.`;
+    console.error(message);
+    // Debug: list source directory to check what IS there
+    try {
+      console.log(`Source directory listing for context:`);
+      const dir = path.dirname(src);
+      console.log(fs.readdirSync(dir || '.'));
+    } catch (e) {
+      console.error('Failed to list source directory:', e);
+    }
+
+    if (['_headers', '_redirects', 'index.html'].includes(path.basename(src))) {
+      throw new Error(message);
+    }
   }
 }
 
@@ -75,6 +87,25 @@ function main() {
     copyFile(file, path.join(DIST, file));
   }
 
+  // Verify critical CSS generation
+  const generatedCssSource = path.join('css', 'tailwind.generated.css');
+  const generatedCssDist = path.join(DIST, 'css', 'tailwind.generated.css');
+
+  if (!fs.existsSync(generatedCssSource) && !fs.existsSync(generatedCssDist)) {
+     console.error('Error: css/tailwind.generated.css was not generated.');
+     try {
+       console.log('Listing css/ directory:');
+       if (fs.existsSync('css')) {
+         console.log(fs.readdirSync('css'));
+       } else {
+         console.log('css/ directory does not exist.');
+       }
+     } catch (e) {
+       console.error('Failed to list css directory:', e);
+     }
+     process.exit(1);
+  }
+
   console.log('Copying directories...');
   for (const dir of DIRS_TO_COPY) {
     copyDir(dir, path.join(DIST, dir));
diff --git a/tests/utils/lruCache.test.mjs b/tests/utils/lruCache.test.mjs
new file mode 100644
index 00000000..199c50fc
--- /dev/null
+++ b/tests/utils/lruCache.test.mjs
@@ -0,0 +1,86 @@
+import { describe, it, beforeEach } from "node:test";
+import assert from "node:assert/strict";
+import { LRUCache } from "../../js/utils/lruCache.js";
+
+describe("LRUCache", () => {
+  let cache;
+
+  beforeEach(() => {
+    cache = new LRUCache({ maxSize: 3 });
+  });
+
+  it("should initialize with default options", () => {
+    const defaultCache = new LRUCache();
+    assert.equal(defaultCache.maxSize, 100);
+    assert.equal(defaultCache.size(), 0);
+  });
+
+  it("should store and retrieve values", () => {
+    cache.set("a", 1);
+    assert.equal(cache.get("a"), 1);
+    assert.equal(cache.has("a"), true);
+    assert.equal(cache.size(), 1);
+  });
+
+  it("should evict oldest item when limit is reached", () => {
+    cache.set("a", 1);
+    cache.set("b", 2);
+    cache.set("c", 3);
+    assert.equal(cache.size(), 3);
+
+    cache.set("d", 4); // Should evict 'a'
+    assert.equal(cache.size(), 3);
+    assert.equal(cache.has("a"), false);
+    assert.equal(cache.get("b"), 2);
+    assert.equal(cache.get("d"), 4);
+  });
+
+  it("should refresh recency on access", () => {
+    cache.set("a", 1);
+    cache.set("b", 2);
+    cache.set("c", 3);
+
+    // Access 'a', making it newest
+    cache.get("a");
+
+    cache.set("d", 4); // Should evict 'b' (oldest is now 'b')
+
+    assert.equal(cache.has("b"), false);
+    assert.equal(cache.has("a"), true);
+    assert.equal(cache.has("c"), true);
+    assert.equal(cache.has("d"), true);
+  });
+
+  it("should update value and refresh recency on set", () => {
+    cache.set("a", 1);
+    cache.set("b", 2);
+    cache.set("c", 3);
+
+    // Update 'a'
+    cache.set("a", 10);
+
+    cache.set("d", 4); // Should evict 'b'
+
+    assert.equal(cache.get("a"), 10);
+    assert.equal(cache.has("b"), false);
+  });
+
+  it("should track stats", () => {
+    cache.set("a", 1);
+    cache.get("a"); // Hit
+    cache.get("b"); // Miss
+
+    const stats = cache.getStats();
+    assert.equal(stats.hits, 1);
+    assert.equal(stats.misses, 1);
+    assert.equal(stats.size, 1);
+    assert.equal(stats.maxSize, 3);
+  });
+
+  it("should clear cache", () => {
+    cache.set("a", 1);
+    cache.clear();
+    assert.equal(cache.size(), 0);
+    assert.equal(cache.getStats().hits, 0);
+  });
+});