html {
    font-weight: 900;
    font-size: 10px;
    color: black;
}
body {
    background-image: linear-gradient(90deg, #516471 0, #1f4459 50%, #002642 100%);
    margin: 50px;
    font-family: sans-serif;
    
}
header {
    background-color: rgba(255, 255, 255, 0.3);
    padding: 10px;
    margin: 10px 0;
    text-align: center;
    color: white;
    border-top: 2px solid black;
    box-shadow: 2px 0 5px black;
}
@media all and (max-width: 1000px) {
    .flex-nav ul {
        flex-wrap: wrap;
    }
    .flex-nav li {
        flex: 1 1 50%;
    }
    .flex-nav .social {
        flex: 1 1 25%;
    }
}
@media all and (max-width: 500px) {
    .flex-nav ul {
        flex-basis: 100%;
    }
    .toggleNav {
        display: block;
    }
    .flex-nav ul {
        display: none;
    }
    .flex-nav ul.open{
        display: flex;
    }
}