body {
    margin: 0px;
}
main {
    margin-left: 20px;
    margin-right: 20px;
}
h1 {
    text-align: center;
}
ul {
    list-style-type: none;
    background-color: black;
    padding: 0px;
    margin: 0px;
    overflow: hidden;
}
a {
    color: white;
    text-decoration: none;
    padding: 15px;
    display: block;
    text-align: center;
}
a:hover {
    background-color: gray;
}
li{
    float: left;
}
.btn {
    padding: 8px 14px;
    cursor: pointer; 
    border: 2px solid black;
    box-shadow: 2px 2px 0 0 white, 4px 4px 0 0 black;
    transition-duration: 200ms;
}
.btn:hover {
    box-shadow: 3px 3px 0 0 white, 6px 6px 0 0 black;
    transform: translate(-2px, -2px);
}
.btn2 {
    padding: 8px 14px;
    cursor: pointer; 
    border: 2px solid black;
    box-shadow: 2px 2px 0 0 white, 4px 4px 0 0 black;
    transition-duration: 200ms;
}
.btn2:hover {
    box-shadow: 3px 3px 0 0 white, 6px 6px 0 0 black;
    transform: translate(-2px, -2px);
}