diff --git a/static/css/nucleus.css b/static/css/nucleus.css
index c764aa5c84..779a7c27af 100644
--- a/static/css/nucleus.css
+++ b/static/css/nucleus.css
@@ -255,6 +255,8 @@ select {
 button,
 input[type="submit"] {
   cursor: pointer;
+  -ms-user-select: none;
+  -webkit-user-select: none;
   user-select: none;
   white-space: nowrap;
   border: inherit; }
diff --git a/static/css/theme.css b/static/css/theme.css
index e510a005f1..6d955a8115 100644
--- a/static/css/theme.css
+++ b/static/css/theme.css
@@ -786,6 +786,8 @@ div.highlight > div td{
 }
 /* disable selection for lineno cells */
 div.highlight > div td:first-child:not(:last-child){
+    -ms-user-select: none;
+    -webkit-user-select: none;
     user-select: none;
 }
 /* increase code column to full width if highlight shortcode was used in table lineno mode  */
@@ -1746,7 +1748,7 @@ input[type="search"]::-webkit-search-results-decoration { display: none; }
 
 .a11y-only {
     /* idea taken from https://www.filamentgroup.com/lab/a11y-form-labels.html */
-    clip: rect(1px,1px,1px,1px);
+    clip-path: polygon(0 0, 1px 0, 1px 1px, 0 1px);
     overflow: hidden;
     position: absolute;
     height: 1px;