How to make a profile intro?

This is one that I found they are called loading screens 

/*LOADING SCREEN!*/

body:before {

content: " ";

height: 100vh;

width: 100vw;

display: block;

position: fixed; 

top: 0; 

left: 0; 

z-index: 100;

background-image: url('https://external-media.spacehey.net/media/s4u8eGuSzj97Uocnk9ChdHhKSvrbS8hrsHAtFkFEi0pI=/https://i.imgur.com/0tVm9gY.gif');

background-size: cover;

background-repeat: repeat;

    background-position:center;

    background-color: black;

animation: yourAnimation 2.5s ease 0s 1 normal forwards;

pointer-events: none;

}

@keyframes yourAnimation { 0.0%{ opacity: 1;} 75%{ opacity: 1; } 100%{ opacity: 0;} }