html {
height: 100%;
background: url(https://s3-us-west-2.amazonaws.com/s.cdpn.io/2017/tiger_lily.jpg);
background-size: cover;
}
div {
/* relevant styles */
border: solid 0.125em;
border-image: linear-gradient(#be4c39, rgba(190, 76, 57, 0) 80%) 1;
padding: 0.125em;
background: linear-gradient(#e18728, rgba(225, 135, 40, 0) 80%) content-box;
/* other styles */
margin: 0 auto;
width: 5em;
height: 3em;
color: white;
font: 700 2em/2 comic sans ms, verdana, sans serif;
text-align: center;
}