body{
    font-family:system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    background-color: linear-gradient(159deg,rgba(2, 0, 36, 1) 0%, rgba(9, 9, 121, 1) 35%, rgba(0, 212, 255, 1) 100%);
    display: block;
    margin: 0;
    padding: 0;
    position: absolute;
    width: 100%;
    height: 100%;
    left: 0;
    top: 0L;
}   
nav{
    margin:1rem 0
}
nav ul{
    margin:0;
    padding:0;
    list-style:none;
    display:flex;
    align-items:flex-start;
}
nav a{
    display:block;
    font-weight:bold;
    text-decoration:none;
    color:rgb(0, 0, 0);
    border:1px solid black;
    padding:0.5rem
}
nav li.active a{
    color:rgb(78, 78, 78);
    background:rgb(251, 255, 0)
}
    .container{
        width:900px;
        margin:auto;
    }