body {
    font-family:arial;
    color: #333;
}

header,footer {
    text-align:center;
    padding: 40px 0;
    background:#dadada;
}

nav ul{
    margin:0;
    padding: 0;
    list-style-type:none;
    border-top: 2px solid #083073;
}

nav ul li a {
	display: block;
	background: #EDBB03;
	padding: 20px 10px;
	text-align: center;
	text-decoration: none;
	text-transform: uppercase;
	color: #fff;
	font-weight: bold;
	border-bottom: 2px solid #083073;
}

main {
    display:block;
    background-color:#f2f2f2;
    padding:20px;
}

@media only screen and (min-width: 600px) {
    #container{
        padding:20px;
        display:flex;
        flex-wrap:wrap;
    }

    header, footer {
        flex:100%;
    }

    nav {
        flex: 1;
        background-color: #f7e5a3;
    }

    main {
        flex:2;
    }
}

@media only screen and (min-width: 1020px) {
    #container {
        width:1020px; /*it will never be wider then 1020px*/
        margin:auto;
    }
    main {
        flex:3;
        display:flex;
    }

    main article:first-of-type{
        margin-right:20px;
    }
}