#myBtn {
    display: none; /* Hidden by default */
    position: fixed; /* Fixed/sticky position */
    bottom: 30px; /* Place the button at the bottom of the page */
    right: 40px; /* Place the button 30px from the right */
    z-index: 99; /* Make sure it does not overlap */
    border: none; /* Remove borders */
    outline: none; /* Remove outline */
    background-color: #CCCCCC; /* Set a background color */
    color: white; /* Text color */
    cursor: pointer; /* Add a mouse pointer on hover */
    padding: 15px; /* Some padding */
    border-radius: 10px; /* Rounded corners */
    height: 50px; /* PN height */
    width: 50px; /* PN width */
    font-size: 20px; /* PN font-size */
    background-position: center center; /* PN background-position */
    background-repeat: no-repeat; /* PN background-repeat */
    background-image: url(https://pcc-cic.org.uk/totop/up-arrow.png); /* PN background-image */
    opacity: 0.8; /* PN opacity */
    transition: 1s; /* PN transition */
}

#myBtn:hover {
    background-color: #0778BE; /* Add a dark-grey background on hover */
    box-shadow: 0 12px 16px 0 rgba(0,0,0,0.24), 0 17px 50px 0 rgba(0,0,0,0.19); /* PN box-shadow */
}