fix: realistic group demos

Note: I'm changing the build workflow node version in the commit also to
address the re-occuring and intermittent issues with builds failing b/c
of playwright not being downloaded. Read more at these issues:
microsoft/playwright#1988
microsoft/playwright#4033 (comment)

Signed-off-by: Matt Hippely <mhippely@vmware.com>

.github/workflows/build.yml

@@ -11,7 +11,8 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-node@v1
         with:
-          node-version: '14.x'
+          node-version: '14'
+          check-latest: true
       - uses: microsoft/playwright-github-action@v1
       - uses: actions/cache@v2
         with:

packages/core/src/navigation/navigation.element.scss

@@ -65,3 +65,7 @@
   height: 100%;
   overflow: auto;
 }
+
+::slotted([slot='cds-navigation-substart']) {
+  width: 100%;
+}