/* Style the element that is used to open and close the accordion class */
        div.accordion {
            background-color: #fff;
            color: #444;
            cursor: pointer;
            padding: 0px;
            width: 100%;
            text-align: left;
            border: none;
            outline: none;
            transition: 0.4s;
            margin-bottom:10px;
            opacity: 0.70;
            filter: alpha(opacity=70);
        }

        /* Add a background color to the accordion if it is clicked on (add the .active class with JS), and when you move the mouse over it (hover) */
        div.accordion.active, div.accordion:hover {
            background: rgb(255,255,255);
            background: linear-gradient(90deg, rgba(255,255,255,1) 0%, rgba(232,231,222,1) 50%, rgba(255,255,255,1) 100%);
            opacity: 1;
            filter: alpha(opacity=100);
        }

        /* Style the element that is used for the panel class */

        div.panel {
            padding: 0 18px;
            background-color: white;
            max-height: 0;
            overflow: hidden;
            transition: 0.4s ease-in-out;
            opacity: 0;
            margin-bottom:10px;
        }

        div.panel.show {
            opacity: 1;
            max-height: 500px; /* Whatever you like, as long as its more than the height of the content (on all screen sizes) */
        }

<script>
        document.addEventListener("DOMContentLoaded", function(event) {
        var acc = document.getElementsByClassName("accordion");
        var panel = document.getElementsByClassName('panel');

        for (var i = 0; i < acc.length; i++) {
            acc[i].onclick = function() {
                var setClasses = !this.classList.contains('active');
                setClass(acc, 'active', 'remove');
                setClass(panel, 'show', 'remove');

                if (setClasses) {
                    this.classList.toggle("active");
                    this.nextElementSibling.classList.toggle("show");
                }
            }
        }

        function setClass(els, className, fnName) {
            for (var i = 0; i < els.length; i++) {
                els[i].classList[fnName](className);
            }
        }

        });
    </script>