diff --git a/apps/theming/css/theming.scss b/apps/theming/css/theming.scss
index e8b00e4165..20b84d2a0d 100644
--- a/apps/theming/css/theming.scss
+++ b/apps/theming/css/theming.scss
@@ -47,6 +47,9 @@
 /* override styles for login screen in guest.css */
 #header .logo {
 	background-image: url(#{$image-logo});
+	@if $theming-logo-mime != '' {
+		background-size: contain;
+	}
 }
 
 #body-login,
diff --git a/core/css/guest.css b/core/css/guest.css
index 0050f198a6..b3a1de6e32 100644
--- a/core/css/guest.css
+++ b/core/css/guest.css
@@ -67,7 +67,7 @@ h3 {
 #header .logo {
 	background-image: url('../img/logo.svg?v=1');
 	background-repeat: no-repeat;
-	background-size: contain;
+	background-size: 175px;
 	background-position: center;
 	width: 256px;
 	min-height: 128px;