What is the z-index in CSS?

[vidushi-tomar-7f335103 (Vidushi Tomar)]

What is the z-index in CSS?

[sakshi-srivastava-f3c2a4a4 (Sakshi Srivastava)]

Z-index allows you to define depth of elements in HTML, so elements with high z-index will always overlap the elements with lower value with z-index.