gistfile1.scss

.full-screen-overlay-modal {
    &__background {
        position: fixed;
        z-index: 1000;
        left: 0;
        top: 0;
        width: 100%;
        height: 100%;
    }
    &__content {
        position: fixed;
        z-index: 2000;
        
        // Closing multiple modals won't work without this line. No idea as to why.
        transform: translateY(4px); 
    }
}