Fixed dimensions of instruction (#306)

When the width of the window is approximately between 880 and 950px, the instructions were not fully contained within the right pane, because of the mismatch between the width of the pane and the instructions. However, this was not visible in the majority of the cases because of the min-width and max-width

Co-authored-by: Dennis Luxen <info@project-osrm.org>

Author: cfalas

css/site.css

@@ -271,7 +271,7 @@
   position: fixed;
   right: 0px;
   top: 60px;
-  width: 45%;
+  width: 33.33%;
   max-width: 340px;
   min-width: 200px;
   height: 95%;