diff --git a/core/src/themes/ionic.mixins.scss b/core/src/themes/ionic.mixins.scss
index 76fe102293..6be878891e 100644
--- a/core/src/themes/ionic.mixins.scss
+++ b/core/src/themes/ionic.mixins.scss
@@ -400,30 +400,9 @@
     }
   } @else {
     @at-root {
-      @supports (inset-inline-start: 0) {
-        & {
-          inset-inline-start: $start;
-          inset-inline-end: $end;
-        }
-      }
-    }
-
-    // TODO FW-3766
-    @at-root {
-      @supports not (inset-inline-start: 0) {
-        & {
-          @include ltr() {
-            left: $start;
-            right: $end;
-          }
-          @include rtl() {
-            left: unset;
-            right: unset;
-
-            left: $end;
-            right: $start;
-          }
-        }
+      & {
+        inset-inline-start: $start;
+        inset-inline-end: $end;
       }
     }
   }