body{
font-family: Arial;
margin:0;
background:#f5f5f5;
}

header{
background:#111;
color:white;
padding:20px;
text-align:center;
}

nav a{
color:white;
margin:10px;
text-decoration:none;
font-weight:bold;
}

section{
background:white;
padding:25px;
margin:20px;
border-radius:6px;
}

footer{
background:#111;
color:white;
text-align:center;
padding:15px;
}

ul{
margin-left:20px;
}

@media(max-width:768px){

nav a{
display:block;
margin:10px;
}

section{
margin:10px;
}

}