fix: remove custom scrollbar

Author: mrholek

scss/sidebar/_sidebar-nav.scss

@@ -11,35 +11,6 @@
   overflow-y: auto;
   list-style: none;
 
-  // Firefox scrollbars
-  @-moz-document url-prefix() {
-    scrollbar-width: thin;
-  }
-
-  // Chrome, Edge scrollbars
-
-  /* total width */
-  &::-webkit-scrollbar {
-    width: 8px;
-    background-color: transparent;
-  }
-
-  /* background of the scrollbar except button or resizer */
-  &::-webkit-scrollbar-track {
-    background-color: transparent;
-  }
-
-  /* scrollbar itself */
-  &::-webkit-scrollbar-thumb {
-    background-color: rgba(0, 0, 0, .375);
-    @include border-radius(8px);
-  }
-
-  /* set button(top and bottom of the scrollbar) */
-  &::-webkit-scrollbar-button {
-    display: none;
-  }
-
   .nav-title {
     padding: $sidebar-nav-title-padding-y $sidebar-nav-title-padding-x;
     margin-top: $sidebar-nav-title-margin-top;