diff --git a/Cask b/Cask
index fce18b13c..c6bb0d652 100644
--- a/Cask
+++ b/Cask
@@ -18,6 +18,7 @@
 
 ;; UI --- core/core-ui.el
 (depends-on "nlinum")
+(depends-on "fill-column-indicator")
 (depends-on "spaceline" :git "https://github.com/TheBB/spaceline")
 
 ;; Evil --- core/core-evil.el
diff --git a/core/core-ui.el b/core/core-ui.el
index 2d788fa5f..ad5ee35e9 100644
--- a/core/core-ui.el
+++ b/core/core-ui.el
@@ -29,6 +29,12 @@
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+(use-package fill-column-indicator
+  :config
+  (setq fci-rule-color "#2b303f")
+  (setq-default fill-column 80)
+  (add-hook! text-mode 'fci-mode))
+
 (use-package nlinum ; line numbers
   :disabled t
   :defer t