diff --git a/lib/jekyll/converters/markdown/kramdown_parser.rb b/lib/jekyll/converters/markdown/kramdown_parser.rb
index 05b94337..d9c9c222 100644
--- a/lib/jekyll/converters/markdown/kramdown_parser.rb
+++ b/lib/jekyll/converters/markdown/kramdown_parser.rb
@@ -12,7 +12,7 @@ module Jekyll
           "line_number_start" => 1,
           "tab_width"         => 4,
           "wrap"              => "div"
-        }
+        }.freeze
 
         def initialize(config)
           Jekyll::External.require_with_graceful_fail "kramdown"
@@ -32,22 +32,44 @@ module Jekyll
           @config["syntax_highlighter_opts"] ||= {}
           @config["coderay"] ||= {} # XXX: Legacy.
           modernize_coderay_config
+          make_accessible
         end
 
         def convert(content)
           Kramdown::Document.new(content, @config).to_html
         end
 
+        private
+        def make_accessible(hash = @config)
+          proc_ = proc { |hash_, key| hash_[key.to_s] if key.is_a?(Symbol) }
+          hash.default_proc = proc_
+
+          hash.each do |_, val|
+            make_accessible val if val.is_a?(
+              Hash
+            )
+          end
+        end
+
         # config[kramdown][syntax_higlighter] > config[kramdown][enable_coderay] > config[highlighter]
         # Where `enable_coderay` is now deprecated because Kramdown
         # supports Rouge now too.
 
         private
         def highlighter
-          @highlighter ||= begin
-            if highlighter = @config["syntax_highlighter"] then highlighter
-            elsif @config.key?("enable_coderay") && @config["enable_coderay"]
-              Jekyll::Deprecator.deprecation_message "You are using 'enable_coderay', use syntax_highlighter: coderay in your configuration file."
+          return @highlighter if @highlighter
+
+          if @config["syntax_highlighter"]
+            return @highlighter = @config[
+              "syntax_highlighter"
+            ]
+          end
+
+          @highlighter = begin
+            if @config.key?("enable_coderay") && @config["enable_coderay"]
+              Jekyll::Deprecator.deprecation_message "You are using 'enable_coderay', " \
+                "use syntax_highlighter: coderay in your configuration file."
+
               "coderay"
             else
               @main_fallback_highlighter
@@ -59,7 +81,13 @@ module Jekyll
         def strip_coderay_prefix(hash)
           hash.each_with_object({}) do |(key, val), hsh|
             cleaned_key = key.gsub(/\Acoderay_/, "")
-            Jekyll::Deprecator.deprecation_message "You are using '#{key}'. Normalizing to #{cleaned_key}." if key != cleaned_key
+
+            if key != cleaned_key
+              Jekyll::Deprecator.deprecation_message(
+                "You are using '#{key}'. Normalizing to #{cleaned_key}."
+              )
+            end
+
             hsh[cleaned_key] = val
           end
         end
@@ -71,7 +99,9 @@ module Jekyll
         private
         def modernize_coderay_config
           if highlighter == "coderay"
-            Jekyll::Deprecator.deprecation_message "You are using 'kramdown.coderay' in your configuration, please use 'syntax_highlighter_opts' instead."
+            Jekyll::Deprecator.deprecation_message "You are using 'kramdown.coderay' in your configuration, " \
+              "please use 'syntax_highlighter_opts' instead."
+
             @config["syntax_highlighter_opts"] = begin
               strip_coderay_prefix(
                 @config["syntax_highlighter_opts"] \