Prevent sidenav panel to shrink

scss/sections/_sidenav.scss

@@ -2,6 +2,7 @@
   @include grid-pad;
   @include panel-margin;
   width: 100%;
+  flex-shrink: 0;
 
   @include media($large-screen) {
     width: 21rem;

templates/styleguide.html.to

@@ -31,7 +31,8 @@
 </div>
 
 <div class='col col--grow'>
-  <div class='panel panel__content'>
+  <div class='panel'>
+    <div class='panel__content'>
 
       <div class="panel__heading">
         <h1>Panel Heading H1</h1>
@@ -74,6 +75,7 @@
         <div class='col col--grow'>col 12</div>
       </div>
     </div>
+  </div>
 
   <div class='panel'>
     Another panel without padding