html {
    background: #2B2A2A;
}

.center {
    display: block;
    width: auto;
    height: auto;
    margin-left: auto;
    margin-right: auto;
    margin-top: 100px;
    width: 40%;
}

h1, h2, h3, h4, h5, h6 {
    color: #222;
    font-weight: 600;
    line-height: 1.3;
}