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: 1;
    }
}

@media only screen and (min-width: 1020px) {
    #container {
        width: 1020px;
        margin: auto;
}
    main {
        flex: 3;
        display: flex;
}
    main article:first-of-type {
        margin-right: 20px;
    }
}