diff --git a/app/sass/_layout.scss b/app/sass/_layout.scss
index d987efd..21b8590 100644
--- a/app/sass/_layout.scss
+++ b/app/sass/_layout.scss
@@ -77,3 +77,8 @@ sub,
 sup {
   font-size: 0.8rem;
 }
+
+sub {
+  display: block;
+  line-height: 1.55;
+}
diff --git a/app/sass/init/_markdown.scss b/app/sass/init/_markdown.scss
index a134629..910bd36 100644
--- a/app/sass/init/_markdown.scss
+++ b/app/sass/init/_markdown.scss
@@ -56,6 +56,7 @@
     font-size: 1rem;
   }
 
+  sub,
   sup {
     @include font-mono;
   }