Revert "chore(styles): adopt bg color for dock background"

This reverts commit de3d5728a62f02c4fe1fbb5c759a28cb7a156003.

styles/dock.css

@@ -1,5 +1,5 @@
 #dock {
-    background-color: @bg;
+    background-color: alpha(#fff, 0.07);
     padding: 4px 4px;
     margin: 4px 4px;
     border: none;
@@ -96,4 +96,4 @@
 /*   min-height: 0px; */
 /*   margin-top: 0px; */
 /*   background-color: transparent; */
-/* } */
+/* } */