diff --git a/app/assets/stylesheets/components/card.css.scss b/app/assets/stylesheets/components/card.css.scss
index 0de3133272..6c7803f00c 100644
--- a/app/assets/stylesheets/components/card.css.scss
+++ b/app/assets/stylesheets/components/card.css.scss
@@ -128,7 +128,7 @@ a.card-title-link:hover {
   margin: 0;
 }
 
-.card-title-text + .card-subtitle-text {
+.card-title-text+.card-subtitle-text {
   margin-top: 0.4em;
 }
 
@@ -191,7 +191,7 @@ a.card-title-link:hover {
   border-top: 1px solid var(--d-divider);
 }
 
-.card-title + .card-border {
+.card-title+.card-border {
   border-top: 0;
 }
 
@@ -230,7 +230,7 @@ a.card-title-link:hover {
   overflow: visible;
 }
 
-.card-nav > .card-title {
+.card-nav>.card-title {
   padding-bottom: 0;
   padding-top: 11px;
 }
@@ -304,7 +304,7 @@ a.card-title-link:hover {
 .nav-tabs.sticky {
   position: sticky;
   top: var(--d-navbar-height);
-  z-index: 9;
+  z-index: 4;
   background-color: var(--d-surface);
 }
 
@@ -371,7 +371,7 @@ a.card-title-link:hover {
   }
 }
 
-.card-supporting-text .course-item + .course-item {
+.card-supporting-text .course-item+.course-item {
   margin-top: 16px;
 }
 
diff --git a/app/assets/stylesheets/models/submissions.css.scss b/app/assets/stylesheets/models/submissions.css.scss
index e31083bf65..3a8843a5b8 100644
--- a/app/assets/stylesheets/models/submissions.css.scss
+++ b/app/assets/stylesheets/models/submissions.css.scss
@@ -279,6 +279,7 @@
   }
 
   table.diff.csv-diff {
+
     td,
     .del,
     .ins,
@@ -329,7 +330,7 @@
       padding-top: 12px;
       position: sticky;
       top: 101px;
-      z-index: 9;
+      z-index: 4;
       background-color: var(--d-surface);
     }