why height don't work if I give % in one div?

Question

when I give one div width:50% and height:40% the div don't show the given value;
please tell me why?
https://code.sololearn.com/WzmbVZh4pLTN/?ref=app

Answer 1

Css % refers to parent tag width/height values, make sure parent tag width/height is set, before use %

Try to add the following css:

html, body {
height: 100%;
}

body {
width: 100%;
}

Answer 2

thanks