Change last css to work for webkit as well

static/css/sass/_nav.scss

@@ -176,7 +176,7 @@ nav {
         @include align-items(center);        // Cross axis alignment.
         @include flex-grow(1);
         @include align-content(space-around);    // Handling of extra space.
-        flex-wrap: wrap;
+        @include flex-wrap(wrap);
     }
 
     // Set to have equal spacing for li link elements.

static/css/usta.css

@@ -531,6 +531,7 @@ nav ul ul li a {
   flex-grow: 1;
   -webkit-align-content: space-around;
   align-content: space-around;
+  -webkit-flex-wrap: wrap;
   flex-wrap: wrap; }
 .horiz-nav .nav-link {
   position: relative;