diff --git a/sahli.coffee b/sahli.coffee
index 043bc09..2bc1dba 100644
--- a/sahli.coffee
+++ b/sahli.coffee
@@ -416,6 +416,8 @@ class @Sahli
           @increaseFont($('pre'), -2)
         when @keycode '9'
           @increaseFont($('pre'), 2)
+        when @keycode '0'
+          $('pre').css("font-size", "2.5vw");
         when 40 # down
           @moveline 1
         when 38 # up
diff --git a/sahli.js b/sahli.js
index 45def1d..f391a42 100644
--- a/sahli.js
+++ b/sahli.js
@@ -487,6 +487,8 @@ l__________/__________|___|______l__________j_____j
               return _this.increaseFont($('pre'), -2);
             case _this.keycode('9'):
               return _this.increaseFont($('pre'), 2);
+            case _this.keycode('0'):
+              return $('pre').css("font-size", "2.5vw");
             case 40:
               return _this.moveline(1);
             case 38: