Accordion static files

accordion.css

/** Accordion styles **/
.accordions {
    background: white;
    padding: 16px 8px;
}

.accordion {
    background-color: white;
    color: #444;
    cursor: pointer;
    padding: 18px;
    width: 100%;
    border: none;
    text-align: left;
    outline: none;
    font-size: 15px;
    transition: 0.4s;
}

.accordion.active, .accordion.accordion:hover {
    background-color: #eee;
}


.accordion-icon{
    color: #777;
    float: right;
    margin-left: 5px;
    opacity: 0.6;
    font-size: 12px;
    border-radius: 20px;
    border: 2px solid #bbb;
    padding: 4px;
    display: inline-block;
    transition: rotate 2s ease-out;
}

.accordion.active .accordion-icon{
    transform: rotate(45deg);
}

.panel.accordion-panel {
    padding: 8px 18px 4px 18px;
    background-color: white;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.2s ease-out;
}

accordion.js

window.addEventListener("load", function(){
    
    var acc = document.getElementsByClassName("accordion");
    var i;
    
    for (i = 0; i < acc.length; i++) {
      acc[i].addEventListener("click", function() {
        this.classList.toggle("active");
        var panel = this.nextElementSibling;
        if (panel.style.maxHeight){
          panel.style.maxHeight = null;
        } else {
          panel.style.maxHeight = panel.scrollHeight + "px";
        } 
      });
    }
    
});