There's a style in your template that is causing this:
div.modal {
transform: translateX(-50%);
}
Our style for computing the margin left is taking the size of the modal, computing half of that and shifting it over by half so the box is centered on the page. The transform style that you have then repositions along the horizontal access by another 50%.
My suggestion is to temporarily add the following to your CSS file. I'll be checking in something similar to our CSS:
div#login-modal.modal {
transform: none;
}
-Melissa
sclogin popup
