diff --git a/src/_locales/en/messages.json b/src/_locales/en/messages.json
index 0eaec54..28da9bb 100644
--- a/src/_locales/en/messages.json
+++ b/src/_locales/en/messages.json
@@ -32,10 +32,10 @@
 		"message": "Theme"
 	},
 	"optionThemeAuto": {
-		"message": "Match System"
+		"message": "System"
 	},
 	"optionThemeCustom": {
-		"message": "Match Firefox"
+		"message": "Browser"
 	},
 	"optionThemeLight": {
 		"message": "Light"
diff --git a/src/_locales/ja/messages.json b/src/_locales/ja/messages.json
index 5966681..3f5a029 100644
--- a/src/_locales/ja/messages.json
+++ b/src/_locales/ja/messages.json
@@ -35,7 +35,7 @@
 		"message": "システムに合わせる"
 	},
 	"optionThemeCustom": {
-		"message": "Firefoxに合わせる"
+		"message": "ブラウザに合わせる"
 	},
 	"optionThemeLight": {
 		"message": "ライトモード（明るい）"