diff --git a/web/static/service/tanabata.webmanifest b/web/static/service/tanabata.webmanifest
index 17ca3dc..29895bd 100644
--- a/web/static/service/tanabata.webmanifest
+++ b/web/static/service/tanabata.webmanifest
@@ -7,6 +7,7 @@
 	"scope": "/",
 	"display": "standalone",
 	"theme_color": "#615880",
+	"background_color": "#312F45",
 	"icons": [
 		{
 			"src": "\/images\/android-icon-36x36.png",