using details/summary
*not* summary/details which might honestly be a better fit.
No-Library (pure JS), HTML, CSS, JavaScript
html5 confetti
No extra markup, just ::after pseudo-element. nested divs are still probably better
animated checkmark
jQuery draggable
QR codes via javascript
An example of how you can implement your own error messages using the constraint validation API.
something to do with forms (no aria)