/* CSS Document */
*{ box-sizing: border-box;}

body {font-family: Arial, Helvetica, sans-serif;}

header {
background-color: rgb(0,0,255);
padding: 30px ;
text-align: center;
font-size: 35px;
color: white; 
}

nav {
float: left;
width: 30%;
height: 1200px;
background: #ccc;
padding: 20px ;
}

nav ul {
list-style-type: none;
padding: 0 ;
}

article {
float: left;
padding: 20px ;
width: 70%;
background: rgb(153,0,255);
height: 1200px;
}

section::after{
content:"";
display: table;
clear: both;
}

footer {
background-color: rgb(102,0,102);
padding: 10px ;
text-align: center;
color: white;
}
@media(max.width:600px){
nav,article {width:100%; height: auto;}
}