diff --git a/src/Configuration/ThemeManifestConfiguration.php b/src/Configuration/ThemeManifestConfiguration.php
index 04b791c..dfdf7e3 100644
--- a/src/Configuration/ThemeManifestConfiguration.php
+++ b/src/Configuration/ThemeManifestConfiguration.php
@@ -18,7 +18,7 @@
 
 class ThemeManifestConfiguration implements ConfigurationInterface
 {
-    public function getConfigTreeBuilder()
+    public function getConfigTreeBuilder(): TreeBuilder
     {
         $treeBuilder = new TreeBuilder('manifest');
         $treeBuilder->getRootNode()
diff --git a/src/Configuration/YamlLoader.php b/src/Configuration/YamlLoader.php
index 7851f43..da646b7 100644
--- a/src/Configuration/YamlLoader.php
+++ b/src/Configuration/YamlLoader.php
@@ -17,12 +17,12 @@
 
 class YamlLoader extends Loader
 {
-    public function load($resource, $type = null)
+    public function load($resource, $type = null): mixed
     {
         return Yaml::parse(file_get_contents($resource));
     }
 
-    public function supports($resource, $type = null)
+    public function supports($resource, $type = null): bool
     {
         return \is_string($resource) && \in_array(pathinfo($resource, \PATHINFO_EXTENSION), ['yaml', 'yml'], true);
     }