Answer by Namith Nimlaka for Flex wrap css issue

Try adding flex-wrap: wrap to both the .primary-container and .secondary-container

.primary-container {  flex: 1 1 33.33333%;  display: flex;  flex-wrap: wrap;}.secondary-container {  display: flex;  flex: 1 1 66.66666%;  flex-wrap: wrap;}

This should allow the child elements to wrap onto new lines when there is not enough space available in the row.