*{
    box-sizing: border-box;
}
body{
    font-family: Arial, Helvetica, sans-serif;
    background-color: skyblue;
}
header h1{
    display: none;
}
#wrapper{
    width: 800px;
    margin: auto;
}
nav{
    width: 200px;
    float: left;
}
main{
    width: 600px;
    float: left;
}
footer{
    clear: both;
    text-align: center;
    background-color: silver;
    padding: 10px;
}
p{
    text-align: justify;
}
nav li {
    margin-bottom: 10px;
    list-style-type: none;
}
nav li:last-child{
    margin-bottom: 0;
}
nav a{
    width: 150px;
    padding: 5px;
    text-decoration: none;
    display: block;
    border-radius: 5px;
    border: 5px gray inset;
    background-color: aliceblue;
    color:black;
    text-align: center;
}
nav a:hover{
    border-radius: 5px;
    border: 5px gray outset;
    background-color: darkblue;
    color: aliceblue;
    text-align: center;
}
nav ul{
    padding-inline-start: 0;
}