diff --git a/backend/internal/web/ui/auth.css b/backend/internal/web/ui/auth.css
index 0c843a0..a719b2b 100644
--- a/backend/internal/web/ui/auth.css
+++ b/backend/internal/web/ui/auth.css
@@ -270,7 +270,7 @@
   font-size: 14px;
   height: 40px;
   letter-spacing: 0.25px;
-  max-width: 400px;
+  margin: 0 auto;
   min-width: min-content;
   outline: none;
   overflow: hidden;
@@ -284,7 +284,7 @@
     box-shadow 0.218s;
   vertical-align: middle;
   white-space: nowrap;
-  width: 100%;
+  width: auto;
 }
 
 .gsi-material-button .gsi-material-button-icon {