body[data-active-category="Cryptography"] {
    background-image: url(https://images.unsplash.com/photo-1535999065027-784d98849cbb?q=80&w=1170&auto=format&fit=crop&ixlib=rb-4.1.0&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D);
}
body[data-active-category="Cryptography"] .top-bar {
    background-color: rgba(245, 229, 229, 0.33);
    box-shadow: none;
}
body[data-active-category="Cryptography"] .left-bar, .week-3 .right-bar {
    background-color: rgba(252, 253, 255, 0.452);
}
body[data-active-category="Cryptography"] .node-label:hover { 
    color: rgb(255, 255, 255);
    text-shadow: 1px 1px 3px rgb(159, 24, 71);
    background-color: rgba(175, 150, 109, 0.1);
 }
body[data-active-category="Cryptography"] .tree-node-switch:hover{
     color: rgb(255, 255, 255);
    text-shadow: 1px 1px 3px rgb(159, 24, 71);
    background-color: rgba(175, 150, 109, 0.1);
}