body{
    margin: 0px;
    padding: 0px;
    overflow-x: hidden;
}
button{
    background: black;
    width: 120px;
    height: 80px;
    position: absolute;
    border: none;
    opacity: 0.0;
}
button#aboutus{
    left: 1000px;
    top: 10px;
}
button#history{
    left: 1160px;
    top: 10px;
}
button#portfolio{
    left: 1325px;
    top: 10px;
}
button#contactus{
    left: 1495px;
    top: 10px;
}
button:hover{
    cursor: pointer;
}
#pdf{
    width: 271px;
    height: 58px;
    left: 825px;
    top: 648px;
}