Suppose there is a Flex-Box #X containing 4 Flex-Items #Y1 ... #Y4 that need to be arranged in the following manner: https://i.sstatic.net/NDix8.png If the output medium is smaller than 60em, the flex-items should be positioned like this: https://i.sstatic.net/drd9v.png
I understand what needs to be done for the HTML aspect, but how should I go about handling the CSS part?