Uniquely highlight choosen section in sitebar

The site bar currently highlights all sections in orange. A request has
been made to uniquely highlight a section of the current document.

Switch the highlighting of the menu entries to blue by standard (a lighten
version of the Apertis blue as the standard blue is too dark) and use
orange for the selected section if needed.

Signed-off-by: Martyn Welch <martyn.welch@collabora.com>

themes/beautifulhugo/layouts/partials/nav.html

@@ -81,7 +81,7 @@
         {{ range sort .Site.Sections.ByTitle }}
           <li class="sidebar-section">
             <a href="{{ .URL | relLangURL }}"
-               {{ if .InSection $section }}id="sidebar-focus"{{end}}>{{ .Title }}</a>
+               {{ if .InSection $section }}id="sidebar-focus" class="sidebar-focus"{{end}}>{{ .Title }}</a>
             <div class="sidebar-pages">
               <ul>
                 {{ range .Pages.ByTitle }}

themes/beautifulhugo/static/css/main.css

@@ -849,10 +849,14 @@ div.notices.tip p:first-child:after {
 }
 
 .sidebar-section a {
-  color: #e67d1e;
+  color: #81a0c6;
   font-family: 'Open Sans', 'Helvetica Neue', Helvetica, Arial, sans-serif;
 }
 
+.sidebar-section .sidebar-focus {
+  color: #e67d1e;
+}
+
 .sidebar ul {
   padding-left: 20px;
 }