body{
font-family: Arial, sans-serif;
margin:0;
background:#f4f4f4;
}

header{
background:#333;
color:white;
padding:20px;
text-align:center;
}

nav a{
color:white;
margin:0 15px;
text-decoration:none;
font-weight:bold;
}

nav a:hover{
text-decoration:underline;
}

main{
padding:20px;
max-width:900px;
margin:auto;
background:white;
}


img{
max-width:100%;
display:block;
margin:20px auto;
}

footer{
text-align:center;
padding:10px;
background:#333;
color:white;
margin-top:20px;
}