diff --git a/editor-style.css b/editor-style.css
index 456097c28..ad22f93b4 100644
--- a/editor-style.css
+++ b/editor-style.css
@@ -58,7 +58,11 @@ h6 {
 	font-size: 0.857142857rem;
 }
 hr {
-	/* TODO */
+	background-color: #ccc;
+	border: 0;
+	height: 1px;
+	margin: 24px;
+	margin-bottom: 1.714285714rem;
 }
 
 /* Text elements */
@@ -109,9 +113,8 @@ cite, em, i {
 cite {
 	border: none;
 }
-
 big {
-	/* TODO */
+	font-size: 128.571429%;
 }
 .mceContentBody blockquote {
 	font-style: italic !important;
@@ -150,10 +153,13 @@ address {
 	margin: 0 0 1.714285714rem;
 }
 del {
-	/* TODO */
+	color: #333;
 }
 ins {
-	/* TODO */
+	background: #fff9c0;
+	border: none;
+	color: #333;
+	text-decoration: none;
 }
 sup,
 sub {
diff --git a/style.css b/style.css
index 9f0dd7c5d..fb5d3c244 100644
--- a/style.css
+++ b/style.css
@@ -122,6 +122,20 @@ video {
 audio:not([controls]) {
 	display: none;
 }
+del {
+	color: #333;
+}
+ins {
+	background: #fff9c0;
+	text-decoration: none;
+}
+hr {
+	background-color: #ccc;
+	border: 0;
+	height: 1px;
+	margin: 24px;
+	margin-bottom: 1.714285714rem;
+}
 sub,
 sup {
 	font-size: 75%;