Enable mobile navigation scrolling

Fixes gohugoio#141

layouts/partials/nav-mobile.html

@@ -1,12 +1,12 @@
 <div  class="globalmenu mobilemenu pb3 dn">
     {{ partial "nav-links-global-mobile.html" . }}
 </div>
-<div  class="docsmenu mobilemenu pb3 dn">
+<div  class="docsmenu mobilemenu pb3 dn overflow-y-auto">
     {{ partial "nav-links-docs-mobile.html" . }}
 </div>
 
 <div class="flex dn-l justify-between">
-  <button class="js-toggle flex-auto dib dn-l f6 tc db mt4-ns ph3 pv2 link mr2 white bg-primary-color-dark hover-bg-primary-color ba b--white-40 w-auto" data-target=".globalmenu">Menu</button>
+  <button class="js-toggle flex-auto dib dn-l f6 tc db ph3 pv2 link mr2 white bg-primary-color-dark hover-bg-primary-color ba b--white-40 w-auto" data-target=".globalmenu">Menu</button>
 
-  <button class="js-toggle flex-auto dib dn-l f6 tc db mt4-ns ph3 pv2 link white bg-primary-color-dark hover-bg-primary-color ba b--white-40 w-auto" data-target=".docsmenu">Docs Menu</button>
+  <button class="js-toggle flex-auto dib dn-l f6 tc db ph3 pv2 link white bg-primary-color-dark hover-bg-primary-color ba b--white-40 w-auto" data-target=".docsmenu">Docs Menu</button>
 </div>

layouts/partials/site-footer.html

@@ -41,7 +41,7 @@
 
     <img src="/images/gopher-side_color.svg" alt="" class="absolute-l bottom-0 dn db-l h4 right-0 z-999"/>
 
-    <div class="bg-primary-color-dark bottom-0 left-0 right-0 dn-l fixed pb3 ph3 w-100">
+    <div class="bg-primary-color-dark bottom-0 left-0 right-0 dn-l fixed pa3 w-100 flex flex-column" style="max-height: 100%">
       {{- partial "nav-mobile.html" . -}}
     </div>