Ionic 4 - How to change side menu background color or make background transparent?

Helo,
I want change side menu background color, i tried few things but not working.

ion-menu{
 ion-content{
     background-color: transparent !important;
 }

 .inner-scroll {
     --background: var(--ion-menu-background);
 }
}

Anyone know how can i change background color in ionic 4 :).

In global scss:

ion-menu{
    --width: 100%;
    --background: #000052;
  }

Pls refer doc for more