CSS Parent Selector

div#demo div.parentElement {
    box-shadow: 0 0 10px 3px green;
}

div#demo div.parentElement:not(.dropped) {
    box-shadow: 0 0 10px 3px red;
}

/* HTML CODE

    <div id="demo">
    
        <div class="parentElement">
            <div class="childElement">
                HAS RED BOX-SHADOW
            </div>
        </div>
        
        <div class="parentElement">
            <div class="childElement dropped">
                HAS GREEN BOX-SHADOW
            </div>
        </div>
        
        <div class="parentElement">
            <div class="childElement">
                HAS RED BOX-SHADOW
            </div>
        </div>
        
    </div>

*/