diff --git a/includes/class-style-package.php b/includes/class-style-package.php
index 0464b20..8d829dc 100644
--- a/includes/class-style-package.php
+++ b/includes/class-style-package.php
@@ -151,7 +151,7 @@ private static function scan_entries( $zip ) {
 					sprintf(
 						/* translators: %s: offending entry name. */
 						__( 'Rejected unsafe archive entry: %s', 'exelearning' ),
-						$name
+						esc_html( $name )
 					)
 				);
 			}
@@ -192,24 +192,23 @@ private static function scan_entries( $zip ) {
 	 */
 	private static function verify_entries( array $entries, $prefix ) {
 		foreach ( $entries as $entry ) {
-			if ( '' === $prefix ) {
-				// Subdirectories at the root are allowed when config.xml is at the root.
-				if ( false !== strpos( $entry['name'], '/' ) ) {
-					continue;
-				}
-			} elseif ( 0 !== strpos( $entry['name'], $prefix ) ) {
+			if ( '' !== $prefix && 0 !== strpos( $entry['name'], $prefix ) ) {
 				return new WP_Error(
 					'zip_mixed_roots',
 					__( 'The archive must contain a single root folder or place all files at the root.', 'exelearning' )
 				);
 			}
+			// Directory entries carry no file type; every file below is still checked.
+			if ( '/' === substr( $entry['name'], -1 ) ) {
+				continue;
+			}
 			if ( ! self::is_allowed_filename( $entry['name'] ) ) {
 				return new WP_Error(
 					'zip_bad_extension',
 					sprintf(
 						/* translators: %s: offending filename. */
 						__( 'File type not allowed in style package: %s', 'exelearning' ),
-						$entry['name']
+						esc_html( $entry['name'] )
 					)
 				);
 			}
diff --git a/languages/exelearning-ca.po b/languages/exelearning-ca.po
index 2e8e389..10b1c7b 100644
--- a/languages/exelearning-ca.po
+++ b/languages/exelearning-ca.po
@@ -635,46 +635,46 @@ msgstr "L'arxiu conté més d'un config.xml."
 msgid "The style package is missing config.xml."
 msgstr "Al paquet d'estil li falta config.xml."
 
-#: includes/class-style-package.php:203
+#: includes/class-style-package.php:198
 msgid "The archive must contain a single root folder or place all files at the root."
 msgstr "L'arxiu ha de contenir una única carpeta arrel o situar tots els fitxers a l'arrel."
 
 #. translators: %s: offending filename.
-#: includes/class-style-package.php:211
+#: includes/class-style-package.php:210
 #, php-format
 msgid "File type not allowed in style package: %s"
 msgstr "Tipus de fitxer no permès al paquet d'estil: %s"
 
-#: includes/class-style-package.php:232
+#: includes/class-style-package.php:231
 msgid "Failed to reopen ZIP archive."
 msgstr "No s'ha pogut tornar a obrir l'arxiu ZIP."
 
-#: includes/class-style-package.php:243
+#: includes/class-style-package.php:242
 msgid "Refused unsafe archive entry during extraction."
 msgstr "S'ha rebutjat una entrada d'arxiu insegura durant l'extracció."
 
-#: includes/class-style-package.php:290
+#: includes/class-style-package.php:289
 msgid "Refused path traversal during extraction."
 msgstr "S'ha rebutjat un salt de ruta durant l'extracció."
 
-#: includes/class-style-package.php:297
-#: includes/class-style-package.php:301
+#: includes/class-style-package.php:296
+#: includes/class-style-package.php:300
 msgid "Failed to create a directory from the archive."
 msgstr "No s'ha pogut crear un directori de l'arxiu."
 
-#: includes/class-style-package.php:306
+#: includes/class-style-package.php:305
 msgid "Failed to read a file from the archive."
 msgstr "No s'ha pogut llegir un fitxer de l'arxiu."
 
-#: includes/class-style-package.php:310
+#: includes/class-style-package.php:309
 msgid "Failed to write an extracted file."
 msgstr "No s'ha pogut escriure un fitxer extret."
 
-#: includes/class-style-package.php:396
+#: includes/class-style-package.php:395
 msgid "config.xml is not valid XML."
 msgstr "config.xml no és XML vàlid."
 
-#: includes/class-style-package.php:401
+#: includes/class-style-package.php:400
 msgid "config.xml must declare a <name> element."
 msgstr "config.xml ha de declarar un element <name>."
 
diff --git a/languages/exelearning-ca_valencia.po b/languages/exelearning-ca_valencia.po
index 66eb4fd..f883f03 100644
--- a/languages/exelearning-ca_valencia.po
+++ b/languages/exelearning-ca_valencia.po
@@ -635,46 +635,46 @@ msgstr "L'arxiu conté més d'un config.xml."
 msgid "The style package is missing config.xml."
 msgstr "Al paquet d'estil li falta config.xml."
 
-#: includes/class-style-package.php:203
+#: includes/class-style-package.php:198
 msgid "The archive must contain a single root folder or place all files at the root."
 msgstr "L'arxiu ha de contenir una única carpeta arrel o situar tots els fitxers a l'arrel."
 
 #. translators: %s: offending filename.
-#: includes/class-style-package.php:211
+#: includes/class-style-package.php:210
 #, php-format
 msgid "File type not allowed in style package: %s"
 msgstr "Tipus de fitxer no permès al paquet d'estil: %s"
 
-#: includes/class-style-package.php:232
+#: includes/class-style-package.php:231
 msgid "Failed to reopen ZIP archive."
 msgstr "No s'ha pogut tornar a obrir l'arxiu ZIP."
 
-#: includes/class-style-package.php:243
+#: includes/class-style-package.php:242
 msgid "Refused unsafe archive entry during extraction."
 msgstr "S'ha rebutjat una entrada d'arxiu insegura durant l'extracció."
 
-#: includes/class-style-package.php:290
+#: includes/class-style-package.php:289
 msgid "Refused path traversal during extraction."
 msgstr "S'ha rebutjat un salt de ruta durant l'extracció."
 
-#: includes/class-style-package.php:297
-#: includes/class-style-package.php:301
+#: includes/class-style-package.php:296
+#: includes/class-style-package.php:300
 msgid "Failed to create a directory from the archive."
 msgstr "No s'ha pogut crear un directori de l'arxiu."
 
-#: includes/class-style-package.php:306
+#: includes/class-style-package.php:305
 msgid "Failed to read a file from the archive."
 msgstr "No s'ha pogut llegir un fitxer de l'arxiu."
 
-#: includes/class-style-package.php:310
+#: includes/class-style-package.php:309
 msgid "Failed to write an extracted file."
 msgstr "No s'ha pogut escriure un fitxer extret."
 
-#: includes/class-style-package.php:396
+#: includes/class-style-package.php:395
 msgid "config.xml is not valid XML."
 msgstr "config.xml no és XML vàlid."
 
-#: includes/class-style-package.php:401
+#: includes/class-style-package.php:400
 msgid "config.xml must declare a <name> element."
 msgstr "config.xml ha de declarar un element <name>."
 
diff --git a/languages/exelearning-de_DE.po b/languages/exelearning-de_DE.po
index fe59264..6f58010 100644
--- a/languages/exelearning-de_DE.po
+++ b/languages/exelearning-de_DE.po
@@ -635,46 +635,46 @@ msgstr "Das Archiv enthält mehr als eine config.xml."
 msgid "The style package is missing config.xml."
 msgstr "Im Stilpaket fehlt die config.xml."
 
-#: includes/class-style-package.php:203
+#: includes/class-style-package.php:198
 msgid "The archive must contain a single root folder or place all files at the root."
 msgstr "Das Archiv muss einen einzigen Stammordner enthalten oder alle Dateien im Stammverzeichnis ablegen."
 
 #. translators: %s: offending filename.
-#: includes/class-style-package.php:211
+#: includes/class-style-package.php:210
 #, php-format
 msgid "File type not allowed in style package: %s"
 msgstr "Dateityp im Stilpaket nicht zulässig: %s"
 
-#: includes/class-style-package.php:232
+#: includes/class-style-package.php:231
 msgid "Failed to reopen ZIP archive."
 msgstr "ZIP-Archiv konnte nicht erneut geöffnet werden."
 
-#: includes/class-style-package.php:243
+#: includes/class-style-package.php:242
 msgid "Refused unsafe archive entry during extraction."
 msgstr "Unsicherer Archiveintrag bei der Extraktion abgelehnt."
 
-#: includes/class-style-package.php:290
+#: includes/class-style-package.php:289
 msgid "Refused path traversal during extraction."
 msgstr "Pfad-Traversal bei der Extraktion abgelehnt."
 
-#: includes/class-style-package.php:297
-#: includes/class-style-package.php:301
+#: includes/class-style-package.php:296
+#: includes/class-style-package.php:300
 msgid "Failed to create a directory from the archive."
 msgstr "Verzeichnis konnte nicht aus dem Archiv erstellt werden."
 
-#: includes/class-style-package.php:306
+#: includes/class-style-package.php:305
 msgid "Failed to read a file from the archive."
 msgstr "Datei konnte nicht aus dem Archiv gelesen werden."
 
-#: includes/class-style-package.php:310
+#: includes/class-style-package.php:309
 msgid "Failed to write an extracted file."
 msgstr "Eine extrahierte Datei konnte nicht geschrieben werden."
 
-#: includes/class-style-package.php:396
+#: includes/class-style-package.php:395
 msgid "config.xml is not valid XML."
 msgstr "config.xml ist kein gültiges XML."
 
-#: includes/class-style-package.php:401
+#: includes/class-style-package.php:400
 msgid "config.xml must declare a <name> element."
 msgstr "config.xml muss ein <name>-Element deklarieren."
 
diff --git a/languages/exelearning-eo.po b/languages/exelearning-eo.po
index c22e3ff..c4bfa32 100644
--- a/languages/exelearning-eo.po
+++ b/languages/exelearning-eo.po
@@ -635,46 +635,46 @@ msgstr "La arkivo enhavas pli ol unu config.xml."
 msgid "The style package is missing config.xml."
 msgstr "En la stilpakaĵo mankas config.xml."
 
-#: includes/class-style-package.php:203
+#: includes/class-style-package.php:198
 msgid "The archive must contain a single root folder or place all files at the root."
 msgstr "La arkivo devas enhavi ununuran radikan dosierujon aŭ meti ĉiujn dosierojn en la radikon."
 
 #. translators: %s: offending filename.
-#: includes/class-style-package.php:211
+#: includes/class-style-package.php:210
 #, php-format
 msgid "File type not allowed in style package: %s"
 msgstr "Dosiertipo ne permesata en la stilpakaĵo: %s"
 
-#: includes/class-style-package.php:232
+#: includes/class-style-package.php:231
 msgid "Failed to reopen ZIP archive."
 msgstr "Ne eblis remalfermi la ZIP-arkivon."
 
-#: includes/class-style-package.php:243
+#: includes/class-style-package.php:242
 msgid "Refused unsafe archive entry during extraction."
 msgstr "Malsekura arkiverero malakceptita dum la malpakado."
 
-#: includes/class-style-package.php:290
+#: includes/class-style-package.php:289
 msgid "Refused path traversal during extraction."
 msgstr "Vojtravado malakceptita dum la malpakado."
 
-#: includes/class-style-package.php:297
-#: includes/class-style-package.php:301
+#: includes/class-style-package.php:296
+#: includes/class-style-package.php:300
 msgid "Failed to create a directory from the archive."
 msgstr "Ne eblis krei dosierujon el la arkivo."
 
-#: includes/class-style-package.php:306
+#: includes/class-style-package.php:305
 msgid "Failed to read a file from the archive."
 msgstr "Ne eblis legi dosieron el la arkivo."
 
-#: includes/class-style-package.php:310
+#: includes/class-style-package.php:309
 msgid "Failed to write an extracted file."
 msgstr "Ne eblis skribi malpakitan dosieron."
 
-#: includes/class-style-package.php:396
+#: includes/class-style-package.php:395
 msgid "config.xml is not valid XML."
 msgstr "config.xml ne estas valida XML."
 
-#: includes/class-style-package.php:401
+#: includes/class-style-package.php:400
 msgid "config.xml must declare a <name> element."
 msgstr "config.xml devas deklari elementon <name>."
 
diff --git a/languages/exelearning-es_ES.po b/languages/exelearning-es_ES.po
index 1751dbe..421c60c 100644
--- a/languages/exelearning-es_ES.po
+++ b/languages/exelearning-es_ES.po
@@ -635,46 +635,46 @@ msgstr "El archivo contiene más de un config.xml."
 msgid "The style package is missing config.xml."
 msgstr "Al paquete de estilo le falta config.xml."
 
-#: includes/class-style-package.php:203
+#: includes/class-style-package.php:198
 msgid "The archive must contain a single root folder or place all files at the root."
 msgstr "El archivo debe contener una única carpeta raíz o tener todos los ficheros en la raíz."
 
 #. translators: %s: offending filename.
-#: includes/class-style-package.php:211
+#: includes/class-style-package.php:210
 #, php-format
 msgid "File type not allowed in style package: %s"
 msgstr "Tipo de archivo no permitido en el paquete de estilo: %s"
 
-#: includes/class-style-package.php:232
+#: includes/class-style-package.php:231
 msgid "Failed to reopen ZIP archive."
 msgstr "No se pudo reabrir el archivo ZIP."
 
-#: includes/class-style-package.php:243
+#: includes/class-style-package.php:242
 msgid "Refused unsafe archive entry during extraction."
 msgstr "Se rechazó una entrada no segura del archivo durante la extracción."
 
-#: includes/class-style-package.php:290
+#: includes/class-style-package.php:289
 msgid "Refused path traversal during extraction."
 msgstr "Se rechazó un intento de escape de ruta durante la extracción."
 
-#: includes/class-style-package.php:297
-#: includes/class-style-package.php:301
+#: includes/class-style-package.php:296
+#: includes/class-style-package.php:300
 msgid "Failed to create a directory from the archive."
 msgstr "No se pudo crear un directorio del archivo."
 
-#: includes/class-style-package.php:306
+#: includes/class-style-package.php:305
 msgid "Failed to read a file from the archive."
 msgstr "No se pudo leer un archivo del archivo comprimido."
 
-#: includes/class-style-package.php:310
+#: includes/class-style-package.php:309
 msgid "Failed to write an extracted file."
 msgstr "No se pudo escribir un archivo extraído."
 
-#: includes/class-style-package.php:396
+#: includes/class-style-package.php:395
 msgid "config.xml is not valid XML."
 msgstr "config.xml no es XML válido."
 
-#: includes/class-style-package.php:401
+#: includes/class-style-package.php:400
 msgid "config.xml must declare a <name> element."
 msgstr "config.xml debe declarar un elemento <name>."
 
diff --git a/languages/exelearning-eu.po b/languages/exelearning-eu.po
index 53b808d..e40fffb 100644
--- a/languages/exelearning-eu.po
+++ b/languages/exelearning-eu.po
@@ -635,46 +635,46 @@ msgstr "Artxiboak config.xml bat baino gehiago ditu."
 msgid "The style package is missing config.xml."
 msgstr "Estilo-paketeari config.xml falta zaio."
 
-#: includes/class-style-package.php:203
+#: includes/class-style-package.php:198
 msgid "The archive must contain a single root folder or place all files at the root."
 msgstr "Artxiboak erro-karpeta bakar bat izan behar du edo fitxategi guztiak erroan jarri."
 
 #. translators: %s: offending filename.
-#: includes/class-style-package.php:211
+#: includes/class-style-package.php:210
 #, php-format
 msgid "File type not allowed in style package: %s"
 msgstr "Estilo-paketean onartzen ez den fitxategi mota: %s"
 
-#: includes/class-style-package.php:232
+#: includes/class-style-package.php:231
 msgid "Failed to reopen ZIP archive."
 msgstr "Ezin izan da ZIP artxiboa berriro ireki."
 
-#: includes/class-style-package.php:243
+#: includes/class-style-package.php:242
 msgid "Refused unsafe archive entry during extraction."
 msgstr "Erauzketa garaian artxibo-sarrera ez segurua baztertu da."
 
-#: includes/class-style-package.php:290
+#: includes/class-style-package.php:289
 msgid "Refused path traversal during extraction."
 msgstr "Erauzketa garaian bide-zeharkatzea baztertu da."
 
-#: includes/class-style-package.php:297
-#: includes/class-style-package.php:301
+#: includes/class-style-package.php:296
+#: includes/class-style-package.php:300
 msgid "Failed to create a directory from the archive."
 msgstr "Ezin izan da artxibotik direktorio bat sortu."
 
-#: includes/class-style-package.php:306
+#: includes/class-style-package.php:305
 msgid "Failed to read a file from the archive."
 msgstr "Ezin izan da artxibotik fitxategi bat irakurri."
 
-#: includes/class-style-package.php:310
+#: includes/class-style-package.php:309
 msgid "Failed to write an extracted file."
 msgstr "Ezin izan da erauzitako fitxategi bat idatzi."
 
-#: includes/class-style-package.php:396
+#: includes/class-style-package.php:395
 msgid "config.xml is not valid XML."
 msgstr "config.xml ez da baliozko XML."
 
-#: includes/class-style-package.php:401
+#: includes/class-style-package.php:400
 msgid "config.xml must declare a <name> element."
 msgstr "config.xml-ek <name> elementu bat deklaratu behar du."
 
diff --git a/languages/exelearning-gl_ES.po b/languages/exelearning-gl_ES.po
index b388104..f74a98e 100644
--- a/languages/exelearning-gl_ES.po
+++ b/languages/exelearning-gl_ES.po
@@ -635,46 +635,46 @@ msgstr "O arquivo contén máis dun config.xml."
 msgid "The style package is missing config.xml."
 msgstr "Ao paquete de estilo fáltalle config.xml."
 
-#: includes/class-style-package.php:203
+#: includes/class-style-package.php:198
 msgid "The archive must contain a single root folder or place all files at the root."
 msgstr "O arquivo debe conter unha única carpeta raíz ou situar todos os ficheiros na raíz."
 
 #. translators: %s: offending filename.
-#: includes/class-style-package.php:211
+#: includes/class-style-package.php:210
 #, php-format
 msgid "File type not allowed in style package: %s"
 msgstr "Tipo de ficheiro non permitido no paquete de estilo: %s"
 
-#: includes/class-style-package.php:232
+#: includes/class-style-package.php:231
 msgid "Failed to reopen ZIP archive."
 msgstr "Non se puido reabrir o arquivo ZIP."
 
-#: includes/class-style-package.php:243
+#: includes/class-style-package.php:242
 msgid "Refused unsafe archive entry during extraction."
 msgstr "Rexeitouse unha entrada de arquivo insegura durante a extracción."
 
-#: includes/class-style-package.php:290
+#: includes/class-style-package.php:289
 msgid "Refused path traversal during extraction."
 msgstr "Rexeitouse un salto de ruta durante a extracción."
 
-#: includes/class-style-package.php:297
-#: includes/class-style-package.php:301
+#: includes/class-style-package.php:296
+#: includes/class-style-package.php:300
 msgid "Failed to create a directory from the archive."
 msgstr "Non se puido crear un directorio do arquivo."
 
-#: includes/class-style-package.php:306
+#: includes/class-style-package.php:305
 msgid "Failed to read a file from the archive."
 msgstr "Non se puido ler un ficheiro do arquivo."
 
-#: includes/class-style-package.php:310
+#: includes/class-style-package.php:309
 msgid "Failed to write an extracted file."
 msgstr "Non se puido escribir un ficheiro extraído."
 
-#: includes/class-style-package.php:396
+#: includes/class-style-package.php:395
 msgid "config.xml is not valid XML."
 msgstr "config.xml non é XML válido."
 
-#: includes/class-style-package.php:401
+#: includes/class-style-package.php:400
 msgid "config.xml must declare a <name> element."
 msgstr "config.xml debe declarar un elemento <name>."
 
diff --git a/languages/exelearning-it_IT.po b/languages/exelearning-it_IT.po
index 9650c3f..87da2ef 100644
--- a/languages/exelearning-it_IT.po
+++ b/languages/exelearning-it_IT.po
@@ -635,46 +635,46 @@ msgstr "L'archivio contiene più di un config.xml."
 msgid "The style package is missing config.xml."
 msgstr "Nel pacchetto di stile manca config.xml."
 
-#: includes/class-style-package.php:203
+#: includes/class-style-package.php:198
 msgid "The archive must contain a single root folder or place all files at the root."
 msgstr "L'archivio deve contenere un'unica cartella radice o collocare tutti i file nella radice."
 
 #. translators: %s: offending filename.
-#: includes/class-style-package.php:211
+#: includes/class-style-package.php:210
 #, php-format
 msgid "File type not allowed in style package: %s"
 msgstr "Tipo di file non consentito nel pacchetto di stile: %s"
 
-#: includes/class-style-package.php:232
+#: includes/class-style-package.php:231
 msgid "Failed to reopen ZIP archive."
 msgstr "Impossibile riaprire l'archivio ZIP."
 
-#: includes/class-style-package.php:243
+#: includes/class-style-package.php:242
 msgid "Refused unsafe archive entry during extraction."
 msgstr "Voce di archivio non sicura rifiutata durante l'estrazione."
 
-#: includes/class-style-package.php:290
+#: includes/class-style-package.php:289
 msgid "Refused path traversal during extraction."
 msgstr "Attraversamento di percorso rifiutato durante l'estrazione."
 
-#: includes/class-style-package.php:297
-#: includes/class-style-package.php:301
+#: includes/class-style-package.php:296
+#: includes/class-style-package.php:300
 msgid "Failed to create a directory from the archive."
 msgstr "Impossibile creare una directory dall'archivio."
 
-#: includes/class-style-package.php:306
+#: includes/class-style-package.php:305
 msgid "Failed to read a file from the archive."
 msgstr "Impossibile leggere un file dall'archivio."
 
-#: includes/class-style-package.php:310
+#: includes/class-style-package.php:309
 msgid "Failed to write an extracted file."
 msgstr "Impossibile scrivere un file estratto."
 
-#: includes/class-style-package.php:396
+#: includes/class-style-package.php:395
 msgid "config.xml is not valid XML."
 msgstr "config.xml non è XML valido."
 
-#: includes/class-style-package.php:401
+#: includes/class-style-package.php:400
 msgid "config.xml must declare a <name> element."
 msgstr "config.xml deve dichiarare un elemento <name>."
 
diff --git a/languages/exelearning-pt_PT.po b/languages/exelearning-pt_PT.po
index 7ad27ab..013ceb5 100644
--- a/languages/exelearning-pt_PT.po
+++ b/languages/exelearning-pt_PT.po
@@ -635,46 +635,46 @@ msgstr "O arquivo contém mais do que um config.xml."
 msgid "The style package is missing config.xml."
 msgstr "Falta config.xml no pacote de estilo."
 
-#: includes/class-style-package.php:203
+#: includes/class-style-package.php:198
 msgid "The archive must contain a single root folder or place all files at the root."
 msgstr "O arquivo deve conter uma única pasta raiz ou colocar todos os ficheiros na raiz."
 
 #. translators: %s: offending filename.
-#: includes/class-style-package.php:211
+#: includes/class-style-package.php:210
 #, php-format
 msgid "File type not allowed in style package: %s"
 msgstr "Tipo de ficheiro não permitido no pacote de estilo: %s"
 
-#: includes/class-style-package.php:232
+#: includes/class-style-package.php:231
 msgid "Failed to reopen ZIP archive."
 msgstr "Falha ao reabrir o arquivo ZIP."
 
-#: includes/class-style-package.php:243
+#: includes/class-style-package.php:242
 msgid "Refused unsafe archive entry during extraction."
 msgstr "Entrada de arquivo insegura recusada durante a extração."
 
-#: includes/class-style-package.php:290
+#: includes/class-style-package.php:289
 msgid "Refused path traversal during extraction."
 msgstr "Travessia de caminho recusada durante a extração."
 
-#: includes/class-style-package.php:297
-#: includes/class-style-package.php:301
+#: includes/class-style-package.php:296
+#: includes/class-style-package.php:300
 msgid "Failed to create a directory from the archive."
 msgstr "Falha ao criar um diretório a partir do arquivo."
 
-#: includes/class-style-package.php:306
+#: includes/class-style-package.php:305
 msgid "Failed to read a file from the archive."
 msgstr "Falha ao ler um ficheiro do arquivo."
 
-#: includes/class-style-package.php:310
+#: includes/class-style-package.php:309
 msgid "Failed to write an extracted file."
 msgstr "Falha ao escrever um ficheiro extraído."
 
-#: includes/class-style-package.php:396
+#: includes/class-style-package.php:395
 msgid "config.xml is not valid XML."
 msgstr "config.xml não é XML válido."
 
-#: includes/class-style-package.php:401
+#: includes/class-style-package.php:400
 msgid "config.xml must declare a <name> element."
 msgstr "config.xml deve declarar um elemento <name>."
 
diff --git a/languages/exelearning-ro_RO.po b/languages/exelearning-ro_RO.po
index 5f43771..4334107 100644
--- a/languages/exelearning-ro_RO.po
+++ b/languages/exelearning-ro_RO.po
@@ -636,46 +636,46 @@ msgstr "Arhiva conține mai mult de un config.xml."
 msgid "The style package is missing config.xml."
 msgstr "Pachetului de stil îi lipsește config.xml."
 
-#: includes/class-style-package.php:203
+#: includes/class-style-package.php:198
 msgid "The archive must contain a single root folder or place all files at the root."
 msgstr "Arhiva trebuie să conțină un singur folder rădăcină sau să plaseze toate fișierele în rădăcină."
 
 #. translators: %s: offending filename.
-#: includes/class-style-package.php:211
+#: includes/class-style-package.php:210
 #, php-format
 msgid "File type not allowed in style package: %s"
 msgstr "Tip de fișier nepermis în pachetul de stil: %s"
 
-#: includes/class-style-package.php:232
+#: includes/class-style-package.php:231
 msgid "Failed to reopen ZIP archive."
 msgstr "Redeschiderea arhivei ZIP a eșuat."
 
-#: includes/class-style-package.php:243
+#: includes/class-style-package.php:242
 msgid "Refused unsafe archive entry during extraction."
 msgstr "Intrare de arhivă nesigură refuzată în timpul extragerii."
 
-#: includes/class-style-package.php:290
+#: includes/class-style-package.php:289
 msgid "Refused path traversal during extraction."
 msgstr "Traversare de cale refuzată în timpul extragerii."
 
-#: includes/class-style-package.php:297
-#: includes/class-style-package.php:301
+#: includes/class-style-package.php:296
+#: includes/class-style-package.php:300
 msgid "Failed to create a directory from the archive."
 msgstr "Crearea unui director din arhivă a eșuat."
 
-#: includes/class-style-package.php:306
+#: includes/class-style-package.php:305
 msgid "Failed to read a file from the archive."
 msgstr "Citirea unui fișier din arhivă a eșuat."
 
-#: includes/class-style-package.php:310
+#: includes/class-style-package.php:309
 msgid "Failed to write an extracted file."
 msgstr "Scrierea unui fișier extras a eșuat."
 
-#: includes/class-style-package.php:396
+#: includes/class-style-package.php:395
 msgid "config.xml is not valid XML."
 msgstr "config.xml nu este XML valid."
 
-#: includes/class-style-package.php:401
+#: includes/class-style-package.php:400
 msgid "config.xml must declare a <name> element."
 msgstr "config.xml trebuie să declare un element <name>."
 
diff --git a/languages/exelearning.pot b/languages/exelearning.pot
index 1a07742..8afe3ac 100644
--- a/languages/exelearning.pot
+++ b/languages/exelearning.pot
@@ -634,46 +634,46 @@ msgstr ""
 msgid "The style package is missing config.xml."
 msgstr ""
 
-#: includes/class-style-package.php:203
+#: includes/class-style-package.php:198
 msgid "The archive must contain a single root folder or place all files at the root."
 msgstr ""
 
 #. translators: %s: offending filename.
-#: includes/class-style-package.php:211
+#: includes/class-style-package.php:210
 #, php-format
 msgid "File type not allowed in style package: %s"
 msgstr ""
 
-#: includes/class-style-package.php:232
+#: includes/class-style-package.php:231
 msgid "Failed to reopen ZIP archive."
 msgstr ""
 
-#: includes/class-style-package.php:243
+#: includes/class-style-package.php:242
 msgid "Refused unsafe archive entry during extraction."
 msgstr ""
 
-#: includes/class-style-package.php:290
+#: includes/class-style-package.php:289
 msgid "Refused path traversal during extraction."
 msgstr ""
 
-#: includes/class-style-package.php:297
-#: includes/class-style-package.php:301
+#: includes/class-style-package.php:296
+#: includes/class-style-package.php:300
 msgid "Failed to create a directory from the archive."
 msgstr ""
 
-#: includes/class-style-package.php:306
+#: includes/class-style-package.php:305
 msgid "Failed to read a file from the archive."
 msgstr ""
 
-#: includes/class-style-package.php:310
+#: includes/class-style-package.php:309
 msgid "Failed to write an extracted file."
 msgstr ""
 
-#: includes/class-style-package.php:396
+#: includes/class-style-package.php:395
 msgid "config.xml is not valid XML."
 msgstr ""
 
-#: includes/class-style-package.php:401
+#: includes/class-style-package.php:400
 msgid "config.xml must declare a <name> element."
 msgstr ""
 
diff --git a/tests/unit/StylePackageTest.php b/tests/unit/StylePackageTest.php
index 34d39f9..b8b3e3f 100644
--- a/tests/unit/StylePackageTest.php
+++ b/tests/unit/StylePackageTest.php
@@ -139,6 +139,104 @@ public function test_validate_bad_extension() {
 		wp_delete_file( $zip_path );
 	}
 
+	/**
+	 * A root-level config.xml must not exempt nested files from the extension
+	 * allowlist: server-executable or server-config files are refused at any depth.
+	 *
+	 * @dataProvider nested_forbidden_entry_provider
+	 *
+	 * @param string $entry Nested entry name.
+	 */
+	public function test_validate_rejects_nested_forbidden_file_when_config_sits_at_the_root( $entry ) {
+		$zip_path = $this->make_zip(
+			array(
+				'config.xml' => $this->sample_config_xml( 'acme' ),
+				'style.css'  => 'body{}',
+				$entry       => 'payload',
+			)
+		);
+		$result = ExeLearning_Style_Package::validate( $zip_path, self::MAX );
+		wp_delete_file( $zip_path );
+		$this->assertInstanceOf( 'WP_Error', $result );
+		$this->assertSame( 'zip_bad_extension', $result->get_error_code() );
+	}
+
+	public function nested_forbidden_entry_provider() {
+		return array(
+			'php'       => array( 'x/shell.php' ),
+			'htaccess'  => array( 'x/.htaccess' ),
+			'user.ini'  => array( 'x/.user.ini' ),
+			'phtml'     => array( 'deep/er/a.phtml' ),
+			'no suffix' => array( 'fonts/LICENSE' ),
+		);
+	}
+
+	/**
+	 * Directory entries carry no file type: archives made by tools that store
+	 * them (most do) validate, with or without a root folder.
+	 */
+	public function test_validate_accepts_directory_entries() {
+		$rooted = $this->make_zip(
+			array(
+				'config.xml'   => $this->sample_config_xml( 'acme' ),
+				'img/'         => null,
+				'img/logo.png' => 'binary',
+			)
+		);
+		$folder = $this->make_zip(
+			array(
+				'acme/'            => null,
+				'acme/config.xml'  => $this->sample_config_xml( 'acme' ),
+				'acme/img/'        => null,
+				'acme/img/logo.png' => 'binary',
+			)
+		);
+		$rooted_result = ExeLearning_Style_Package::validate( $rooted, self::MAX );
+		$folder_result = ExeLearning_Style_Package::validate( $folder, self::MAX );
+		wp_delete_file( $rooted );
+		wp_delete_file( $folder );
+		$this->assertIsArray( $rooted_result );
+		$this->assertIsArray( $folder_result );
+		$this->assertSame( 'acme/', $folder_result['prefix'] );
+	}
+
+	/**
+	 * A directory outside the package's root folder still breaks the single-root
+	 * rule, even though directories carry no file type.
+	 */
+	public function test_validate_rejects_a_directory_outside_the_root_folder() {
+		$zip_path = $this->make_zip(
+			array(
+				'acme/'           => null,
+				'acme/config.xml' => $this->sample_config_xml( 'acme' ),
+				'acme/style.css'  => 'body{}',
+				'evil/'           => null,
+			)
+		);
+		$result = ExeLearning_Style_Package::validate( $zip_path, self::MAX );
+		wp_delete_file( $zip_path );
+		$this->assertInstanceOf( 'WP_Error', $result );
+		$this->assertSame( 'zip_mixed_roots', $result->get_error_code() );
+	}
+
+	/**
+	 * Rejection messages quote the entry name escaped, since core prints
+	 * settings errors without escaping.
+	 */
+	public function test_validate_escapes_entry_name_in_error_message() {
+		$zip_path = $this->make_zip(
+			array(
+				'config.xml'               => $this->sample_config_xml( 'acme' ),
+				'<img src=x onerror=1>.x' => 'x',
+			)
+		);
+		$result = ExeLearning_Style_Package::validate( $zip_path, self::MAX );
+		wp_delete_file( $zip_path );
+		$this->assertInstanceOf( 'WP_Error', $result );
+		$this->assertStringNotContainsString( '<img', $result->get_error_message() );
+		$this->assertStringContainsString( '&lt;img', $result->get_error_message() );
+	}
+
 	public function test_validate_accepts_root_package() {
 		$zip_path = $this->make_zip(
 			array(
@@ -294,6 +392,8 @@ public function allowed_filename_provider() {
 			'css'          => array( 'style.css', true ),
 			'svg nested'   => array( 'icons/a.svg', true ),
 			'php'          => array( 'evil.php', false ),
+			'php upper'    => array( 'x/SHELL.PHP', false ),
+			'htaccess'     => array( 'x/.htaccess', false ),
 			'no extension' => array( 'Makefile', false ),
 			'directory'    => array( 'assets/', false ),
 			'empty'        => array( '', false ),
@@ -423,6 +523,10 @@ private function make_zip( array $entries ) {
 		$zip = new ZipArchive();
 		$this->assertTrue( true === $zip->open( $path, ZipArchive::CREATE ) );
 		foreach ( $entries as $name => $contents ) {
+			if ( '/' === substr( $name, -1 ) ) {
+				$zip->addEmptyDir( rtrim( $name, '/' ) );
+				continue;
+			}
 			$zip->addFromString( $name, $contents );
 		}
 		$zip->close();
diff --git a/tests/unit/StylesServiceTest.php b/tests/unit/StylesServiceTest.php
index e34ebd8..5bd1185 100644
--- a/tests/unit/StylesServiceTest.php
+++ b/tests/unit/StylesServiceTest.php
@@ -509,7 +509,6 @@ public function test_build_theme_registry_override_publishes_icons_from_icons_fo
 				'icons/alert.svg'      => '<svg/>',
 				'icons/photo.JPG'      => 'JPEG',
 				'icons/readme.txt'     => 'ignore',
-				'icons/no-extension'   => 'ignore',
 			)
 		);
 		$this->assertIsArray( ExeLearning_Styles_Service::install_from_zip( $zip_path ) );