Answers for "how to give box size in html"

box sizing css

/*universial selector example to include padding, border, and margin 
in all box sizing totals*/
* {
  box-sizing: border-box;
}
/*example of div that will total 100% and not exceed it because it
is using the border-box property*/
div {
box-sizing: border-box;
width: 100%;
border: solid #5B6DCD 10px;
padding: 5px;
margin: 10px;
}

box sizing

html {
	box-sizing: border-box;
}

*, 
*:before, *:after {
	box-sizing: inherit;
}