@sacred As you say, this is an issue with Squarespace 7.1. The same code will work perfectly well on Squarespace 7.0.
The issue occurs because Squarespace 7.1 has a renamed header class that is the same as the one used by the healcode widget, and this causes a conflict that prevents the widget from working properly. This causes a number of issues when the widget is added to 7.1, the most obvious being the disabling of pointer events (that prevents a user from clicking or tapping on the widget) and some formatting issues. If you add this to Design > Custom CSS it should fix this specific issue:
div.healcode .header {
position: relative!important;
pointer-events: auto;
}
Let me know how you get on.
-Paul