html {
	background: gray;
}
body {
    background: lightgray;
    display: flex;
    flex-flow: row wrap;
    max-width: 1280px;
    margin: 0 auto;
    font-family: Verdana;
}
#nav_button {
	display: none;
}
header {
	background: blue;
	position: relative;
	z-index: 10;
  	width: 100%;
}
h1 {
	color: white;
	font-size: 48px;
	text-transform: uppercase;
	text-align: center;
	font-family: Verdana;
	margin: 0;
	padding: 25px;
}
nav {
	width: 25%;
}
nav a {
	display: block;
	background: lightcoral;
	color: white;
	text-decoration: none;
	padding: 5px 10px;
	margin: 5px 0;
}
nav a.active {
	color: darkblue;
	font-weight: bold;
}
nav a:hover {
	background: white;
	color: lightcoral;
}
main {
	background: white;
	min-height: 400px;
	width: 75%;
	box-sizing: border-box;
	padding: 10px 20px;
}
main img {
    display: block;
    border: 1px solid black;
    width: 50%;
    float: right;
    margin: 0 0 20px 20px;
}
footer {
	background: darkblue;
	color: white;
	text-align: center;
  	width: 100%;
  	padding: 10px;
}
footer p {
	margin: 0;
	padding: 5px;
}

@media screen and (max-width:1200px) {
	h1{
		font-size: 42px;
	}
	nav {
		width: 100%;
		text-align: center;
	}
	nav a {
		display: inline-block;
		margin: 0;
	}
	main {
		width: 100%;
	}
}

@media screen and (max-width:500px) {
	h1 {
		font-size: 28px;
	}
	nav {
		transition: margin-top 0.5;
		position: relative;
		margin-top: -150px;
	}
	nav.open {
		margin-top: 0;
	}
	nav a {
		display: block;
		margin: 2px;
		font-size: 20px;
	}
	main img {
		width: 100%;
	}
	#nav_button{
        display: block;
        position: absolute;
        bottom: -12px;
        right: 20px;
        box-sizing: border-box;
        padding: 5px 10px;
        border: 1px solid black;
        background: gray;
        color: limegreen;
        font-weight: bold;
        text-align: center;
    }
    #nav_button:hover{
        background: black;
        cursor: pointer;
    }
}