diff --git a/lib/ace/theme/clouds_midnight.css b/lib/ace/theme/clouds_midnight.css
index 8d23bcbe..3b932996 100644
--- a/lib/ace/theme/clouds_midnight.css
+++ b/lib/ace/theme/clouds_midnight.css
@@ -48,7 +48,7 @@
 }
 
 .ace-clouds-midnight .ace_invisible {
-  color: #BFBFBF
+  color: #666
 }
 
 .ace-clouds-midnight .ace_keyword,
diff --git a/lib/ace/theme/github.css b/lib/ace/theme/github.css
index a897b65e..213d3fd3 100644
--- a/lib/ace/theme/github.css
+++ b/lib/ace/theme/github.css
@@ -109,7 +109,10 @@
 .ace-github .ace_marker-layer .ace_selected-word {
   background: rgb(250, 250, 255);
   border: 1px solid rgb(200, 200, 250);
+}
 
+.ace-github .ace_invisible {
+  color: #BFBFBF
 }
 
 .ace-github .ace_print-margin {
diff --git a/lib/ace/theme/katzenmilch.css b/lib/ace/theme/katzenmilch.css
index e2526b93..0b5a7a23 100644
--- a/lib/ace/theme/katzenmilch.css
+++ b/lib/ace/theme/katzenmilch.css
@@ -55,6 +55,10 @@
   border: 1px solid rgba(100, 5, 208, 0.27)
 }
 
+.ace-katzenmilch .ace_invisible {
+  color: #BFBFBF
+}
+
 .ace-katzenmilch .ace_fold {
   background-color: rgba(2, 95, 73, 0.97);
   border-color: rgba(15, 0, 9, 1.0)
diff --git a/lib/ace/theme/kuroir.css b/lib/ace/theme/kuroir.css
index 9c0ba6a8..5e987abc 100644
--- a/lib/ace/theme/kuroir.css
+++ b/lib/ace/theme/kuroir.css
@@ -49,6 +49,10 @@
   border: 1px solid rgba(245, 170, 0, 0.57);
 }
 
+.ace-kuroir .ace_invisible {
+  color: #BFBFBF
+}
+
 .ace-kuroir .ace_fold {
   border-color: #363636;
 }