Box shadow
A
B
C
body {
margin: 0;
padding: 0;
}
.container {
position: relative;
height: 100vh;
width: 100%;
background-color: #dddde2;
}
.neu {
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
display: flex;
}
.neu div {
width: 200px;
height: 200px;
margin: 30px;
display: flex;
border: outset 5px #e7e7ee;
border-radius: 50px;
justify-content: center;
align-items: center;
font-size: 60px;
box-shadow: 5px 5px 5px #6b6b6e, -5px -5px 5px #c1c1c5;
background-image: linear-gradient(45deg, #F8F8FF, #d8d8dd);
}