Style sub nav links in Graphs

app/views/projects/graphs/_head.html.haml

-- page_specific_javascripts asset_path("graphs/application.js")
-%ul.nav-links
+%ul.nav-links.sub-nav
+  %div{ class: (container_class) }
+
+    - page_specific_javascripts asset_path("graphs/application.js")
     = nav_link(action: :show) do
       = link_to 'Contributors', namespace_project_graph_path
     = nav_link(action: :commits) do

app/views/projects/graphs/ci.html.haml

+- @no_container = true
 - page_title "Continuous Integration", "Graphs"
 = render 'head'
-.row-content-block.append-bottom-default
+
+%div{ class: (container_class) }
+  .row-content-block.append-bottom-default
     .oneline
       A collection of graphs for Continuous Integration
 
-#charts.ci-charts
+  #charts.ci-charts
     .row
       .col-md-6
         = render 'projects/graphs/ci/overall'

app/views/projects/graphs/commits.html.haml

+- @no_container = true
 - page_title "Commits", "Graphs"
 = render 'head'
 
-.row-content-block.append-bottom-default
+%div{ class: (container_class) }
+  .row-content-block.append-bottom-default
     .tree-ref-holder
       = render 'shared/ref_switcher', destination: 'graphs_commits'
     %ul.breadcrumb.repo-breadcrumb
       = commits_breadcrumbs
 
-%p.lead
+  %p.lead
     Commit statistics for
     %strong #{@ref}
     #{@commits_graph.start_date.strftime('%b %d')} - #{@commits_graph.end_date.strftime('%b %d')}
 
-.row
+  .row
     .col-md-6
       %ul
         %li
@@ -36,7 +38,7 @@
         %p.slead
           Commits per day of month
         %canvas#month-chart
-.row
+  .row
     .col-md-6
       %div
         %p.slead

app/views/projects/graphs/languages.html.haml

+- @no_container = true
 - page_title "Languages", "Graphs"
 = render 'head'
 
-.row-content-block.append-bottom-default
+%div{ class: (container_class) }
+  .row-content-block.append-bottom-default
     .oneline
       Programming languages used in this repository
 
-.row
+  .row
     .col-md-8
       %canvas#languages-chart{ height: 400 }
     .col-md-4

app/views/projects/graphs/show.html.haml

+- @no_container = true
 - page_title "Contributors", "Graphs"
 = render 'head'
 
-.row-content-block.append-bottom-default
+%div{ class: (container_class) }
+  .row-content-block.append-bottom-default
     .tree-ref-holder
       = render 'shared/ref_switcher', destination: 'graphs'
     %ul.breadcrumb.repo-breadcrumb
       = commits_breadcrumbs
 
-.loading-graph
+  .loading-graph
     .center
       %h3.page-title
         %i.fa.fa-spinner.fa-spin
         Building repository graph.
       %p.slead Please wait a moment, this page will automatically refresh when ready.
 
-.stat-graph.hide
+  .stat-graph.hide
     .header.clearfix
       %h3#date_header.page-title
       %p.light