.form-container
{
    position: absolute;
    top: 45%;
    left: 50%;
    width: 550px;
    padding: 30px;
    transform: translate(-50%, -50%);
    background: aliceblue;
    box-sizing: border-box;
    box-shadow: 0 15px 25px rgba(0,0,0,.6);
    border-radius: 10px;
}