--- a/mobile/android/themes/core/config.css
+++ b/mobile/android/themes/core/config.css
@@ -38,17 +38,21 @@ body {
     height: 2em;
     border: 1px solid transparent;
     border-image-source: url("chrome://browser/skin/images/textfield.png");
     border-image-slice: 1 1 3 1;
     border-image-width: 1px 1px 3px 1px;
     overflow: hidden;
     display: flex;
     flex-direction: row;
-    float: inline-end;
+    float: right;
+}
+
+#filter-container:dir(rtl) {
+    float: left;
 }
 
 #filter-input {
     -moz-appearance: none;
     border: none;
     background-image: none;
     background-color: transparent;
     display: inline-block;
@@ -74,17 +78,21 @@ body {
 #new-pref-toggle-button {
     background-position: center center;
     background-image: url("chrome://browser/skin/images/config-plus.png");
     background-size: 48px 48px;
     height: 48px;
     width: 48px;
     display: inline-block;
     outline-style: none;
-    float: inline-start;
+    float: left;
+}
+
+#new-pref-toggle-button:dir(rtl) {
+    float: right;
 }
 
 #filter-search-button {
     background-image: url("chrome://browser/skin/images/search.png");
     background-size: 32px 32px;
     height: 32px;
     width: 32px;
     display: inline-block;