IP Address Tracker using VueJS

I want to receive your feedback about my solution code because I realized that my CSS code works different between browsers specially over Mozilla. First of all I used to debug my website over Chrome but when I uploaded the final code the proportions of the screen change, then It's possible to see different the IP tracker between both of last mentioned browsers. Also if you have an advice about good practices using VueJS (till now not the complete framework but CDN library) I will be grateful. Thanks for your help!