diff --git a/test/bundler/css/wpt/background-computed.test.ts b/test/bundler/css/wpt/background-computed.test.ts
index cd762d81b1..78cf1c35b7 100644
--- a/test/bundler/css/wpt/background-computed.test.ts
+++ b/test/bundler/css/wpt/background-computed.test.ts
@@ -16,7 +16,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-/* ../../a.css */
+/* a.css */
 h1 {
     ${property}: ${expected};
 }
diff --git a/test/bundler/css/wpt/color-computed-rgb.test.ts b/test/bundler/css/wpt/color-computed-rgb.test.ts
index 61552d3fea..4743bb4ccd 100644
--- a/test/bundler/css/wpt/color-computed-rgb.test.ts
+++ b/test/bundler/css/wpt/color-computed-rgb.test.ts
@@ -16,7 +16,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-/* ../../a.css */
+/* a.css */
 h1 {
     color: ${expected};
 }
diff --git a/test/bundler/css/wpt/color-computed.test.ts b/test/bundler/css/wpt/color-computed.test.ts
index b1a0731ee1..d71e647fef 100644
--- a/test/bundler/css/wpt/color-computed.test.ts
+++ b/test/bundler/css/wpt/color-computed.test.ts
@@ -15,7 +15,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-/* ../../a.css */
+/* a.css */
 h1 {
     color: ${expected};
 }
diff --git a/test/bundler/css/wpt/relative_color_out_of_gamut.test.ts b/test/bundler/css/wpt/relative_color_out_of_gamut.test.ts
index 64669d3e18..18c5e65d2d 100644
--- a/test/bundler/css/wpt/relative_color_out_of_gamut.test.ts
+++ b/test/bundler/css/wpt/relative_color_out_of_gamut.test.ts
@@ -17,7 +17,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-/* ../../a.css */
+/* a.css */
 h1 {
     color: #00f942;
 }
@@ -38,7 +38,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: rgb(from lab(100 104.3 -50.9) r g b);
   }
@@ -59,7 +59,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: rgb(from lab(0 104.3 -50.9) r g b);
   }
@@ -80,7 +80,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: rgb(from lch(100 116 334) r g b);
   }
@@ -101,7 +101,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: rgb(from lch(0 116 334) r g b);
   }
@@ -122,7 +122,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: rgb(from oklab(1 .365 -.16) r g b);
   }
@@ -143,7 +143,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: rgb(from oklab(0 .365 -.16) r g b);
   }
@@ -164,7 +164,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: rgb(from oklch(1 .399 336.3) r g b);
   }
@@ -185,7 +185,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: rgb(from oklch(0 .399 336.3) r g b);
   }
@@ -206,7 +206,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: #00f942;
   }
@@ -227,7 +227,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hsl(from lab(100 104.3 -50.9) h s l);
   }
@@ -248,7 +248,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hsl(from lab(0 104.3 -50.9) h s l);
   }
@@ -269,7 +269,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hsl(from lch(100 116 334) h s l);
   }
@@ -290,7 +290,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hsl(from lch(0 116 334) h s l);
   }
@@ -311,7 +311,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hsl(from oklab(1 .365 -.16) h s l);
   }
@@ -332,7 +332,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hsl(from oklab(0 .365 -.16) h s l);
   }
@@ -353,7 +353,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hsl(from oklch(1 .399 336.3) h s l);
   }
@@ -374,7 +374,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hsl(from oklch(0 .399 336.3) h s l);
   }
@@ -395,7 +395,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: #00f942;
   }
@@ -416,7 +416,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hwb(from lab(100 104.3 -50.9) h w b);
   }
@@ -437,7 +437,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hwb(from lab(0 104.3 -50.9) h w b);
   }
@@ -458,7 +458,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hwb(from lch(100 116 334) h w b);
   }
@@ -479,7 +479,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hwb(from lch(0 116 334) h w b);
   }
@@ -500,7 +500,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hwb(from oklab(1 .365 -.16) h w b);
   }
@@ -521,7 +521,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hwb(from oklab(0 .365 -.16) h w b);
   }
@@ -542,7 +542,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hwb(from oklch(1 .399 336.3) h w b);
   }
@@ -563,7 +563,7 @@ h1 {
 
     onAfterBundle(api) {
       api.expectFile("/out.css").toEqualIgnoringWhitespace(`
-  /* ../../a.css */
+  /* a.css */
   h1 {
       color: hwb(from oklch(0 .399 336.3) h w b);
   }
diff --git a/test/bundler/expectBundled.ts b/test/bundler/expectBundled.ts
index 13d9764c95..52a831568f 100644
--- a/test/bundler/expectBundled.ts
+++ b/test/bundler/expectBundled.ts
@@ -649,13 +649,18 @@ function expectBundled(
 
     return (async () => {
       // Prepare virtual files with dedent applied for strings, preserve binary content as-is
+      // Use relative paths (strip leading /) to get consistent path comments in CSS output
       const virtualFiles: Record<string, string | Buffer | Uint8Array | Blob> = {};
       for (const [file, contents] of Object.entries(files)) {
-        virtualFiles[file] = typeof contents === "string" ? dedent(contents) : contents;
+        const relativePath = file.startsWith("/") ? file.slice(1) : file;
+        virtualFiles[relativePath] = typeof contents === "string" ? dedent(contents) : contents;
       }
 
+      // Convert entrypoints to relative paths too
+      const relativeEntryPoints = entryPoints.map(ep => (ep.startsWith("/") ? ep.slice(1) : ep));
+
       const build = await Bun.build({
-        entrypoints: entryPoints,
+        entrypoints: relativeEntryPoints,
         files: virtualFiles,
         target,
         format,