Need Error-Produced CSS Class/es

This is a hard to describe, and I have searched but to no avail. What I want to do, I realize, while probably doable, may be a bit of a challenge. I’ll lay out the details:

The booking form I linked to I was able to create with the following Plugins: Contact Form 7, Collapse-O-Matic, Conditional Fields for Contact Form 7, Contact Form 7 External Shortcodes, Contact Form DB, Honeypot for Contact Form 7, and Newsletters – Contact Form 7 Subscribers.

This booking form has served me very well since 2016. Works great. No issues, though obviously there is some complexity in such a form. I do plan to move the form [response] soon placing it above the Submit button, but this isn’t related to that.

Note that now when the form is submitted the current error message appears below the form and it indicates that there is an error SOMEWHERE in the form (usually a missed required field), and that the “boxes” don’t reveal the error’s actual location inviting the user to go looking for it. What a pain. It could be so much better, right?

Sure would be nice if the Collapse-o-Matic box, a DIV, could be styled IF an error was located within said box/DIV. The solution needs to be a clever one.

So from this I know that each box’s div would 1) need to be added to that DIV -OR- 2) each box would need a different CSS class added on_error.

In the former scenario (1) the classes would have to be added to the DIV, using PHP I suppose, and that should be fine. I can run PHP on the pages of this site.

In the latter scenario (2) the form error residing within that box or DIV would need to produce a common class used in any of the boxes in which error-producing inputs were contained.

The desired result: The user hits Submit with, say, the required Name* input in Step 1, and let’s say the Date/Date Range in Step 5, just as an example. As is the inputs themselves are highlight, but I’d also like to highlight the box or DIV in the corresponding steps.

I hope what I’m looking for is clear, and I hope I am able to get some viable suggestions. Thanks.

Mike

The page I need help with: [log in to see the link]