Hey Patrick,
I have just checked your site and these is a block of code that is adding a padding to buttons which is causing the shift in the modal close button:
Try updating the code to:
button:not(.x-modal-close):hover {
background-color: white;
border-radius: 5px;
Font-family: "ff-meta-headline-web-pro",sans-serif;
font-size: 16px;
border: none;
font-style: normal;
font-weight: 700;
line-height: 1;
letter-spacing: 0;
text-align: center;
text-transform: uppercase;
color: rgb(249,126,181);
margin-top: 10px;
padding: 0.75em 1.5em 0.75em 1.5em;
}
Kindly note that since this is a custom code that changes the default behavior/display of the theme, you will be responsible to maintain or update the code in case you require further changes or if the code stops working in future updates. If you are uncertain how to proceed, it would be best to get in touch with a developer.
Hope this helps.