Suddenly my CSS *hide on mobile* doesn't apply

Hi.

I've used CSS code many times in order to hide elements on mobile or desktop with succes. I've used this code for mobile: 

/* Hide this on Mobile */
@media screen and (max-width:640px) {
    [data-section-id="64beb96412f80705c61f0ed9"] {
        display: none;
    }
}

But all of the sudden it doesn't appear when I try to hide a element. It just sticks to the page. 

Does any of you know a solution to this? 

Can you share your website URL and the page this section is on?

URL: https://malenemosevang.dk/ 

Page: https://malenemosevang.dk/personlig-traening-1 

But I've just tried to apply the css code to other pages and the same issue is there. I've had succes using the code earlier this week, but suddenly yesterday it gave up 😅

Have you got the Section ID correct? I can't see that section ID on desktop or mobile on the page you shared.

The code works fine in my testing

I've deleted the code again since it didn't work. For example if I wan't to hide the header on this page: https://malenemosevang.dk/personlig-traening I inset this code: 

/* Hide this on Mobile */
@media screen and (max-width:640px) {
    [data-section-id="64beb5b2745beb236d5d6668"] {
        display: none;
    }
}

Isn't that correct?

Ah I can see when I visit the site that the code actually applies - it just doesn't apply in the preview in squarespace which it use to do? 

I wonder if you have an error somewhere in your Custom CSS that is causing this problem? It should apply in the editor and preview if everything is working correctly.

Hmm.. That's possible but not sure to figure out if or where the mistake is.

You can share it here, and I can try and find any errors.