common/static/common/styles/_forms.sass

@@ -14,6 +14,10 @@
     // TODO: @web-assets improve component style
     height: calc(var(--spacer) * 3.5)
 
+.invalid-feedback
+  ul
+    +padding(3, left)
+
 /* Override Tagger's styling. */
 .was-validated .form-control:invalid,
 .form-control.is-invalid