Use system focus styles by default

packages/@uppy/core/src/_common.scss

@@ -22,8 +22,8 @@
 // }
 
 .uppy-Root *:focus {
-  outline: $size-focus-outline solid $blue; /* no !important */
-  outline-offset: $size-focus-offset; /* no !important */
+  // outline: $size-focus-outline solid $blue; /* no !important */
+  // outline-offset: $size-focus-offset; /* no !important */
 
   // outline: none;
   // box-shadow: inset 0 0 0 2px rgba($blue, 0.5);