diff --git a/app/assets/stylesheets/application.scss b/app/assets/stylesheets/application.scss
index b756759a..72c7788d 100644
--- a/app/assets/stylesheets/application.scss
+++ b/app/assets/stylesheets/application.scss
@@ -25,6 +25,10 @@ $spacers: (
   2-plus: 0.75rem
 );
 
+$sizes: (
+  "70ch": 70ch,
+);
+
 @import "bootstrap";
 @import "editor";
 
diff --git a/app/views/bootstrap/_alert.haml b/app/views/bootstrap/_alert.haml
index 0fb3d2d3..395f75d2 100644
--- a/app/views/bootstrap/_alert.haml
+++ b/app/views/bootstrap/_alert.haml
@@ -1,2 +1,2 @@
-.alert.alert-primary{ role: 'alert', class: local_assigns[:class] }
+.alert.alert-primary.mx-auto.content.max-w-70ch{ role: 'alert', class: local_assigns[:class] }
   = yield