* {
    box-sizing: border-box;
}

body {
    font-family: poppins;
}

.first,.parent {
    width: 700px;
    margin: 20px auto;
    padding: 24px;
    background-color: #eee;
}

.stick_to_bottom {
    display: block;
    padding: 12px;
    background-color: orange;
    color: black;
    width: 100%;
}

.is_sticky {
    position: fixed;
    bottom: 0;
    left: 50%;
    transform: translate(-50%,-50%);
    width: 50%;
    box-shadow: 0px 4px 5px rgba(0,0,0,.7);
    border: 0;
}

@media screen and (max-width:768px) {
    div {
        width: 100% !important;
    }
}