body, #pdfContainer, #mainContent {
    -webkit-user-select: none; /* Chrome/Safari */
    -moz-user-select: none; /* Firefox */
    -ms-user-select: none; /* IE/Edge */
    user-select: none;
}

/* Prevent dragging or touch callout on mobile */
body, #pdfContainer, #mainContent {
    -webkit-touch-callout: none;
    -webkit-user-drag: none;
}