Make nav-title 100% width in mobile viewport (#928)

Fixes: rdar://137436968

Author: marinaaisa

src/components/NavBase.vue

@@ -679,11 +679,11 @@ $content-max-width: map-deep-get($breakpoint-attributes, (nav, large, content-wi
   align-items: center;
   white-space: nowrap;
   box-sizing: border-box;
+  overflow: hidden;
 
   @include breakpoint(small, $scope: nav) {
     padding-top: 0;
     height: $nav-height-small;
-    width: 90%;
   }
 
   :deep(span) {

src/components/Tutorial/NavigationBar.vue

@@ -259,7 +259,6 @@ export default {
 
 .nav :deep(.nav-title) {
   grid-column: 1;
-  width: 90%;
   padding-top: 0;
 }