diff --git a/_config.yml b/_config.yml
index ee519f1..5602aa9 100644
--- a/_config.yml
+++ b/_config.yml
@@ -127,38 +127,6 @@ marked:
     nofollow: false
   disableNunjucks: false
   descriptionLists: true
-# markdown_it_plus:
-#   highlight: true
-#   html: true
-#   xhtmlOut: true
-#   breaks: true
-#   langPrefix:
-#   linkify: true
-#   typographer:
-#   quotes: “”‘’
-#   pre_class: highlight
-#   plugins:
-#     - plugin:
-#         name: markdown-it-mark
-#         enable: true
-#     - plugin:
-#         name: markdown-it-toc-and-anchor
-#         enable: true
-#         options:
-#           toc: true
-#           tocClassName: 'markdown-toc'
-#           tocFirstLevel: 2
-#           tocLastLevel: 6
-#           tocCallback:
-#           anchorLink: true
-#           anchorLinkSymbol: '#'
-#           anchorFirstLevel: 2
-#           anchorLastLevel: 6
-#           anchorLinkSpace: false
-#           anchorLinkSymbolClassName:
-#           anchorLinkBefore: true
-#           anchorClassName: 'markdown-anchor'
-#           resetIds: true
 toc:
   maxdepth: 3
   class: toc
@@ -168,6 +136,10 @@ toc:
     position: after
     symbol: '#'
     style: header-anchor
+sub:
+  markup: '&'
+sup:
+  markup: '&'
 mathjax:
   tags: none
   single_dollars: true