fix: #fe kbd size in portrait mobile

frontend/src/css/keyboard.scss

@@ -13,7 +13,7 @@ $key-width: 8vw; // 100/12 ~ 8.3
   overflow: hidden;
   width: 100%;
   height: 100%;
-  max-height: 30vh;
+  max-height: min(40vh, 6 * $key-width);
 
   /* rows layout */