Grid Flex Error

6

I add im my css that col-30 to works

.col-30 {-webkit-box-flex: 0;-webkit-flex: 0 0 30%;-moz-box-flex: 0;-moz-flex: 0 0 30%;-ms-flex: 0 0 30%;flex: 0 0 30%;max-width: 30%;}