防止元素在php文档中移动 -

Currently experiencing a slight issue with a cart I'm building -

What it should look like :-

What happens when I resize : -

Any help would be greatly appreciated.

I have attached the necessary file(s) below :)

index.php https://hastebin.com/otuzowuwir.xml

css/style.css https://hastebin.com/vapunugeka.css

You shouldn't have more than 1 head, body and html tag in your page. To help you with your code you should use an IDE. W3C is also a great tool to check for errors https://validator.w3.org/