Check below for code:
div.tucked-corners {
background: #f6f6f6;
height: 380px;
margin: 50px auto;
padding: 10px;
position: relative;
width: 580px;
-webkit-box-shadow: 0 1px 7px hsla(0,0%,0%,.2);
-moz-box-shadow: 0 1px 7px hsla(0,0%,0%,.2);
box-shadow: 0 1px 7px hsla(0,0%,0%,.2);
}
span.tucked-corners {
background: #c4453c;
display: block;
height: 380px;
position: relative;
width: 580px;
-webkit-box-shadow: inset 0 0 10px hsla(0,0%,0%,.25);
-moz-box-shadow: inset 0 0 10px hsla(0,0%,0%,.25);
box-shadow: inset 0 0 10px hsla(0,0%,0%,.25);
}
/* Top Corner Effect */
.top-corners:after,
.top-corners:before {
background: #e6e6e6;
content: '';
height: 50px;
position: absolute;
top: -25px;
width: 100px;
z-index: 10;
-webkit-box-shadow: 0 6px 9px -8px hsla(0,0%,0%,.5);
-moz-box-shadow: 0 6px 9px -8px hsla(0,0%,0%,.5);
box-shadow: 0 6px 9px -8px hsla(0,0%,0%,.5);
}
.top-corners:after {
left: -50px;
-webkit-transform: rotate(-45deg);
-moz-transform: rotate(-45deg);
-ms-transform: rotate(-45deg);
-o-transform: rotate(-45deg);
transform: rotate(-45deg);
}
.top-corners:before {
right: -50px;
-webkit-transform: rotate(45deg);
-moz-transform: rotate(45deg);
-ms-transform: rotate(45deg);
-o-transform: rotate(45deg);
transform: rotate(45deg);
}
/* Bottom Corner Effect */
.bottom-corners:after,
.bottom-corners:before {
background: #e6e6e6;
content: '';
height: 50px;
position: absolute;
bottom: -25px;
width: 100px;
-webkit-box-shadow: 0 6px 9px -8px hsla(0,0%,0%,.5);
-moz-box-shadow: 0 6px 9px -8px hsla(0,0%,0%,.5);
box-shadow: 0 6px 9px -8px hsla(0,0%,0%,.5);
}
.bottom-corners:after {
left: -50px;
-webkit-transform: rotate(-135deg);
-moz-transform: rotate(-135deg);
-ms-transform: rotate(-135deg);
-o-transform: rotate(-135deg);
transform: rotate(-135deg);
}
.bottom-corners:before {
right: -50px;
-webkit-transform: rotate(135deg);
-moz-transform: rotate(135deg);
-ms-transform: rotate(135deg);
-o-transform: rotate(135deg);
transform: rotate(135deg);
}