Centering techniques

///////////
//Default//
///////////
div {
margin: 0 auto;
}

//////////////////
//Using absolute//
//////////////////
.wrapper {
    position: relative;
}
.insided {
position: absolute;
left: 50%; //top: 50%;
transform: translateX(-50%); //transform: translateY(-50%);
}
//////////////////
//Using flex box//
//////////////////
div {
    display: flex;

    -webkit-justify-content: center;
    -ms-flex-pack: center;
    justify-content: center;

    -webkit-flex-align: center;
    -ms-flex-align: center;
    align-items: center;
}