align element in the middle css code example

Example 1: css center

// example 1 
div { display: grid; place-items: center; }

// example 3
div{ display:flex; align-items:center; }

// example 3
div { width: 100%; margin: 0 auto; }

Example 2: how to center a div element

/*ADD MARGIN auto to left and right*/
.box1{
    width:80%;
    margin:0 auto;
}