main {
    background: #fefefe;
}

h1 {
    margin: 0;
    padding: 0;
    text-align: center;
}

div.formules {
    padding: 50px 100px;
}
div.formule {
    margin: 20px 0;
    background: #fff;
    padding: 50px;
    border-radius: 16px;
    box-shadow: 1px 1px 5px 1px rgba(0,0,0,0.1);
}