diff --git a/prisma/test-phase3-ui.js b/prisma/test-phase3-ui.js
index b7b5491..77f4388 100644
--- a/prisma/test-phase3-ui.js
+++ b/prisma/test-phase3-ui.js
@@ -125,6 +125,7 @@ async function runTests() {
 
   const page = await browser.newPage();
   await page.setViewport({ width: 1280, height: 800 });
+  await page.emulateMediaFeatures([{ name: 'prefers-color-scheme', value: 'dark' }]);
 
   // Helper to set value of React-controlled inputs natively
   const setReactInput = async (selector, value) => {
diff --git a/prisma/test-phase4-ui.js b/prisma/test-phase4-ui.js
index e046af2..f0c998c 100644
--- a/prisma/test-phase4-ui.js
+++ b/prisma/test-phase4-ui.js
@@ -135,6 +135,7 @@ async function runTests() {
 
   const page = await browser.newPage();
   await page.setViewport({ width: 1280, height: 800 });
+  await page.emulateMediaFeatures([{ name: 'prefers-color-scheme', value: 'dark' }]);
 
   // --- TEST 1: ROLE SEGREGATION (COLLABORATOR BLOCKED) ---
   console.log("\n[Test 1] Logging in as collaborator and verifying block on /sales/import...");
diff --git a/prisma/test-phase5-ui.js b/prisma/test-phase5-ui.js
index 8744b0e..510f481 100644
--- a/prisma/test-phase5-ui.js
+++ b/prisma/test-phase5-ui.js
@@ -211,6 +211,7 @@ async function runTests() {
 
   const page = await browser.newPage();
   await page.setViewport({ width: 1280, height: 800 });
+  await page.emulateMediaFeatures([{ name: 'prefers-color-scheme', value: 'dark' }]);
 
   // Helper to set value of React-controlled inputs natively
   const setReactInput = async (selector, value) => {