Add `top: 0` to rnc__base

[MuhammadSawalhy]

The component was working fine until I made some layout changes then I noticed that the notifications are no longer shown. After some inspection, I found the element with rnc__base and I added top: 0 to its styles:

.rnc__base {
+   top: 0;
    height: 100%;
    pointer-events: none;
    position: fixed;
    width: 100%;
    z-index: 9000;
}