Update nicescroll to scss.

src/styles/global/_nicescroll.scss

@@ -18,23 +18,23 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
-.nicescroll::-webkit-scrollbar {
+
-width: 8px;
+.nicescroll {
-height: 8px;
+  &::-webkit-scrollbar {
     background-color: $background;
     border: solid transparent;
-}
+    height: 8px;
-
+    width: 8px;
-.nicescroll::-webkit-scrollbar:hover {
+    &:hover {
       background-color: $background;
       border-left: 1px solid rgba(0,0,0,.12);
       border-right: 1px solid rgba(0,0,0,.12);
     }
-
-.nicescroll::-webkit-scrollbar-thumb {
-background: rgba(0,0,0,0.2);
   }
-
+  &::-webkit-scrollbar-thumb {
-.nicescroll::-webkit-scrollbar-thumb:active {
+    background: rgba(0,0,0,0.2);
+    &:active {
       background: rgba(0,0,0,0.4);
     }
+  }
+}