VueJS IP Address Tracker With Leaflet Map

I did everything well it seems except for one thing: I couldn't have the blue border set in half with the IP Address Stats Card. It's possible to do so if the width is set to a certain amount of pixels but becomes complicated when the window is resized. Not sure how to solve this unless I could somehow get the height of the current div and set the margin-bottom to 50% of that. How did you all solve this?