*{
    margin: 0;
    box-sizing: border-box;
}
div {
    width: 50vw;
    margin: auto;
    background: #ffff66;
    text-align: center;
}
header{
    background-color: aqua;
}
header h1{
    color: darkblue;
    font-size: calc(4px + 4vw);
}
header p{
    font-size: calc(2px + 2vw);
}
nav{
    background-color: bisque;
}
nav ul{
    padding-left: 0;
}
nav ul li{
    display: inline;
    font-size: calc(1px + 2.5vw);
    margin: 3%

}
nav li a, footer a{
    text-decoration: none;
    color: darkblue;
}
nav li a:hover, footer a:hover{
    color: forestgreen;
}
main{
    background-color: orange;

}
main p{
    color: seagreen;
    border: 5px #12a dashed;
    font-size: calc(2px + 2vw);
}
footer{
    background-color: bisque;
}
header p, footer p{
    font-size: calc(2px + 2vw);
}
iframe{
    max-width: 100%;
}