Resize Poster Image Text For Mobile

Site URL: https://sprout-lime-ldyy.squarespace.com/newborn-session

Hi! I am trying to make the text on my poster image blocks responsive to the image in mobile so that the text stays within the square image (below the Session Style section). I am wondering if there might be some custom code that would help?

https://sprout-lime-ldyy.squarespace.com/newborn-session

Password: BRP+D2020

Add to Home > Design > Custom CSS

/* Session style */
@media screen and (max-width:767px) {
div#page-section-5f3d49685256010f80eaeffc .image-inset {
    padding-bottom: 150% !important;
}
}

Thank you. That increased the padding but I was hoping to be able to make the text stay within the constraints of the image (the square shape) just as it is on the desktop site. 

adjust 150%, then save & refresh your site. You won't see no change unless refresh.