Use open-color directly (#1371)

src/shapes.tsx

@@ -1,4 +1,5 @@
 import React from "react";
+import oc from "open-color";
 
 // We inline font-awesome icons in order to save on js size rather than including the font awesome react library
 export const SHAPES =
@@ -57,7 +58,7 @@ export const SHAPES =
             y1="3"
             x2="6"
             y2="3"
-            stroke="#000"
+            stroke={oc.black}
             strokeLinecap="round"
           />
         </svg>