neumorphism

border-radius: 50px;
background: #535ef3;
box-shadow:  -21px -21px 42px #4750cf, 
             21px 21px 42px #5f6cff;

border-radius: 50px;
background: #ffffff;
box-shadow: inset 5px 5px 10px #b5b5b5, 
            inset -5px -5px 10px #ffffff;

box-shadow: 20px 20px 50px #00d2c6, 
            -30px -30px 60px #00ffff;

border-radius: 50px;
background: #535ef3;
box-shadow:  21px 21px 42px #4750cf, 
             -21px -21px 42px #5f6cff;

border-radius: 50px;
background: linear-gradient(145deg, #4da7db, #5bc6ff);
box-shadow:  23px 23px 52px #4aa1d3, 
             -23px -23px 52px #60d1ff;