Fix Nginx 413 error for PDF uploads and html2canvas hidden styling

frontend/nginx.conf

@@ -1,6 +1,7 @@
 server {
     listen 80;
     server_name localhost;
+    client_max_body_size 50M;
 
     location /api/ {
         proxy_pass http://limelite-api:5000;

frontend/src/AnalysisResultPage.jsx

@@ -216,7 +216,6 @@ const AnalysisResultPage = () => {
             let generatedPdfLink = verificationLink;
             if (reportRef.current) {
                 const reportElement = reportRef.current;
-                reportElement.style.display = 'block';
                 
                 try {
                     const canvas = await html2canvas(reportElement, {
@@ -241,15 +240,21 @@ const AnalysisResultPage = () => {
                         method: 'POST',
                         body: fd
                     });
+                    
+                    if (!saveRes.ok) {
+                        throw new Error(`Server returned ${saveRes.status} for PDF upload`);
+                    }
+
                     const saveData = await saveRes.json();
                     
                     if (saveData.success) {
                         generatedPdfLink = `${API_BASE_URL}${saveData.link}`;
+                    } else {
+                        console.error("Backend failed to save PDF:", saveData);
                     }
                 } catch(err) {
                     console.error("Failed to generate/upload PDF during save:", err);
-                } finally {
-                    reportElement.style.display = 'none';
+                    alert("PDF Generation/Upload Error: " + err.message);
                 }
             }
 
@@ -860,7 +865,9 @@ const AnalysisResultPage = () => {
             <div
                 ref={reportRef}
                 style={{
-                    display: 'none',
+                    position: 'absolute',
+                    top: '-9999px',
+                    left: '-9999px',
                     width: '210mm',
                     minHeight: '297mm',
                     backgroundColor: '#ffffff',