https://obw-emden.de/wp-content/themes/yootheme-obw/builder/hd-flipcard/js/hd-flipcard.js?ver=4.3.5

1function setBackSize() {
2
3	let flipcards = document.querySelectorAll('.hd-flipcard');
4
5	let i = flipcards.length;
6
7	while (i--) {
8
9		let flipcard = flipcards[i],
10		    front    = flipcard.querySelector('.el-card'),
11		    back     = flipcard.querySelector('.el-card-back');
12
13		front.style.removeProperty('min-height');
14		back.style.removeProperty('height');
15
16
17		if (front.offsetHeight < back.offsetHeight) {
18			front.style.minHeight = back.offsetHeight + 'px';
19		} else {
20			back.style.height = '100%';
21		}
22
23	}
24
25};
26
27window.addEventListener('load', setBackSize);
28window.addEventListener('resize', setBackSize);