Extend Markdown preprocessor to add anchors in main headers only "h2"

Author: federicobucchi

_plugins/convert-header.rb

@@ -0,0 +1,19 @@
+module Kramdown
+  module Converter
+    class Html
+      def convert_header(el, indent)
+        el_attribute = el.attr.dup
+
+        if @options[:auto_ids] && !el_attribute['id']
+          el_attribute['id'] = generate_id(el.options[:raw_text])
+        end
+
+        el_attribute['class'] = "header-with-anchor"
+
+        @toc << [el.options[:level], el_attribute['id'], el.children] if el_attribute['id'] && in_toc?(el)
+        level = output_header_level(el.options[:level])
+        format_as_block_html("h#{level}", el_attribute, "#{inner(el, indent)} <a href=\"##{el_attribute['id']}\">#</a>", indent)
+      end
+    end
+  end
+end

assets/stylesheets/_screen.scss

@@ -177,16 +177,16 @@ cite {
   }
 }
 
-h2.with-anchor {
+h2.header-with-anchor {
   &:hover {
     a {
       display: inline-block;
     }
   }
 
   a {
-    color: var(--color-text);
     display: none;
+    color: var(--color-text);
     margin-left: .2em;
     text-decoration: none;
   }