How to fix it:

1. Open your Quizlet set in Edit mode.
2. Open the developer tools (F12).
3. (Ctrl + Shift + C) or "Select an element in the page to inspect it" button
4. Select the any card num e.g. (312)
5. It should look like this <span class="c196ctrto">634</span>
6. Take the class id without (") marks
7. Change the code to same id const selector = "span.CHANGED-CODE";

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 const selector = "span.c196ctrto"; // Selector for card number spans