diff --git a/firefox/userChrome.css b/firefox/userChrome.css
new file mode 100644
index 0000000..59ead17
--- /dev/null
+++ b/firefox/userChrome.css
@@ -0,0 +1,37 @@
+/* Remove Multi-Containers icon from address bar*/
+#pageAction-urlbar-_testpilot-containers {
+  display: none !important;
+}
+
+/* Add numbers to tabs */
+tabs {
+  counter-reset: tab-counter;
+}
+
+tab:nth-child(1) .tab-content::before,
+tab:nth-child(2) .tab-content::before,
+tab:nth-child(3) .tab-content::before,
+tab:nth-child(4) .tab-content::before,
+tab:nth-child(5) .tab-content::before,
+tab:nth-child(6) .tab-content::before,
+tab:nth-child(7) .tab-content::before,
+tab:nth-child(8) .tab-content::before,
+tab:nth-child(9) .tab-content::before {
+  counter-increment: tab-counter;
+  content: counter(tab-counter) "";
+
+  position: absolute;
+  left: 20px;
+  top: 10px;
+  padding: 0px 4px;
+  border-radius: 7px;
+  z-index: 100;
+
+  opacity: 0.5;
+  backdrop-filter: blur(20px);
+  
+  font-weight: bold;
+  font-size: 80%;
+}
+
+