--- a/browser/themes/shared/tabs.inc.css
+++ b/browser/themes/shared/tabs.inc.css
@@ -799,16 +799,20 @@
 .all-tabs-item[selected] {
   box-shadow: inset 4px 0 var(--blue-40);
 }
 
 .all-tabs-item[selected]:-moz-locale-dir(rtl) {
   box-shadow: inset -4px 0 var(--blue-40);
 }
 
+.all-tabs-item[selected] > .all-tabs-button {
+  font-weight: bold;
+}
+
 .all-tabs-button {
   list-style-image: url("chrome://mozapps/skin/places/defaultFavicon.svg");
 }
 
 .all-tabs-secondary-button > label {
   display: none;
   margin: 0 5.5px;
 }