Use preferCSSPageSize: true for exact print preview matching

server.js

@@ -45,20 +45,20 @@ app.post('/api/generate_pdf', async (req, res) => {
     // Inject styles to ensure 100% width and print media simulation
     await page.addStyleTag({
         content: `
-            @page { margin: 0; size: A4; }
+            @page { margin: 10mm; size: A4; }
             body { -webkit-print-color-adjust: exact; }
         `
     });
 
     // Generate PDF
     const pdfBuffer = await page.pdf({
-      format: 'A4',
       printBackground: true,
+      preferCSSPageSize: true,
       margin: {
-        top: '10mm',
-        bottom: '10mm',
-        left: '10mm',
-        right: '10mm'
+        top: 0,
+        bottom: 0,
+        left: 0,
+        right: 0
       }
     });