If i add box-sizing to border-box in the code my divs donot stay in the box,How to manage this?

*{ // if b0x-sizing is uncommented then the div's overflow and donot stay in the box //box-sizing: border-box; margin: 0; padding: 0; } #main { width: 140px; height: 300px; border: 1px solid #000000; display: flex; flex-flow: row wrap; align-content: space-around; }

#main div {
width: 70px;
height: 70px;

please show a live example of what you are doing (perhaps with codepen)