diff --git a/scss/_input-group.scss b/scss/_input-group.scss
index 3f5d7080ae..bf69ddb41d 100644
--- a/scss/_input-group.scss
+++ b/scss/_input-group.scss
@@ -17,6 +17,7 @@
   > .custom-file {
     position: relative; // For focus state's z-index
     flex: 1 1 0%;
+    min-width: 0; // https://stackoverflow.com/questions/36247140/why-dont-flex-items-shrink-past-content-size
     margin-bottom: 0;
 
     + .form-control,