Improve wiki rendering. Fix pygemnt + markdown invalid html

app/assets/stylesheets/gitlab_bootstrap/files.scss

@@ -43,11 +43,15 @@
         padding: 0 4px;
       }
       padding: 20px;
-      h1, h2 {
-        line-height: 46px;
-      }
-      h3, h4 {
-        line-height: 40px;
+
+      h1 { font-size: 26px; line-height: 46px; }
+      h2 { font-size: 22px; line-height: 42px; }
+      h3 { font-size: 20px; line-height: 40px; }
+      h4 { font-size: 18px; line-height: 32px; }
+      h5 { font-size: 16px; line-height: 26px; }
+
+      .white .highlight pre {
+        background: #f5f5f5;
       }
     }
 

lib/redcarpet/render/gitlab_html.rb

@@ -11,14 +11,13 @@ class Redcarpet::Render::GitlabHTML < Redcarpet::Render::HTML
 
   def block_code(code, language)
     options = { options: {encoding: 'utf-8'} }
+    options.merge!(lexer: language.downcase) if Pygments::Lexer.find(language)
 
-    h.content_tag :div, class: h.user_color_scheme_class do
-      if Pygments::Lexer.find(language)
-        Pygments.highlight(code, options.merge(lexer: language.downcase))
-      else
-        Pygments.highlight(code, options)
-      end.html_safe
-    end
+    <<-HTML
+       <div class="#{h.user_color_scheme_class}">
+         #{Pygments.highlight(code, options)}
+       </div>
+    HTML
   end
 
   def postprocess(full_document)