--- a/browser/themes/shared/incontentprefs/preferences.inc.css
+++ b/browser/themes/shared/incontentprefs/preferences.inc.css
@@ -48,16 +48,25 @@ treecol {
   font-weight: normal;
   white-space: nowrap;
 }
 
 .accessory-button {
   min-width: 145px;
 }
 
+/* Override search textbox highlight color */
+.main-content textbox[type="search"]:hover {
+  border-color: #6a6868;
+}
+
+.main-content textbox[type="search"][focused="true"] {
+  border-color: var(--in-content-border-focus);
+}
+
 /* Category List */
 
 #categories {
   max-height: 100vh;
 }
 
 #categories > scrollbox {
   overflow-x: hidden !important;