#main_container{
    position: absolute;
    display: flex;
    flex-direction: column;
    width: 400px;
    left: 50%;
    top: 50%;

    border: 1px solid black;
    border-radius: 5px;
    transform: translate(-50%, -50%);
    background-color: lightgray;
}

#title_bloc{
    text-align: center;
    font-variant: small-caps;
    font-size: 1.2em;
}

ul, li {
    list-style: none;
    margin: 0;
    padding: 8px 16px;
}

li a:visited, li a {
    color: blue;
    text-decoration: none;
}