Enable HTTP/2 & HTTP/3

.htaccess

@@ -2,11 +2,44 @@ Options +FollowSymLinks
 
 RewriteEngine on
 
+# Redirect duplicate homepage URLs (/main.html and /index.php) to canonical root /
+RewriteRule ^main\.html$ / [R=301,L]
+RewriteCond %{THE_REQUEST} \s/+index\.php[\s?] [NC]
+RewriteCond %{QUERY_STRING} ^$
+RewriteRule ^index\.php$ / [R=301,L]
+
+# Clean URL routing for .html pages
 RewriteCond %{REQUEST_FILENAME} !-f
 RewriteCond %{QUERY_STRING} ([a-zA-Z0-9-_.=&+%]*)
 RewriteRule ^([0-9a-zA-Z\-]+).html$ index.php?action=$1&%1 [L]
 
+# Custom 404 handler
+ErrorDocument 404 /index.php?action=404
+
+# Advertise HTTP/3 (h3) support via Alt-Svc header
+<IfModule mod_headers.c>
+    Header setIfEmpty Alt-Svc "h3=\":443\"; ma=86400"
+</IfModule>
+
+# Gzip / Deflate Compression for Core Web Vitals & PageSpeed
+<IfModule mod_deflate.c>
+    AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css application/xml application/xhtml+xml application/rss+xml application/javascript application/x-javascript application/ld+json image/svg+xml
+</IfModule>
+
+# Browser Caching for Static Assets
+<IfModule mod_expires.c>
+    ExpiresActive On
+    ExpiresByType image/jpeg "access plus 1 month"
+    ExpiresByType image/png "access plus 1 month"
+    ExpiresByType image/gif "access plus 1 month"
+    ExpiresByType image/x-icon "access plus 1 month"
+    ExpiresByType image/svg+xml "access plus 1 month"
+    ExpiresByType text/css "access plus 1 month"
+    ExpiresByType application/javascript "access plus 1 month"
+    ExpiresByType application/pdf "access plus 7 days"
+    ExpiresByType font/ttf "access plus 1 year"
+</IfModule>
+
 <Files .htaccess>
-    order allow,deny
-    deny from all
+    Require all denied
 </Files>