simple and minimal accordion

accordion-snippet.html

<!-- A very simple and minimal accordion with icons and expand animations -->

<style>
/* Style the buttons to open and close the accordion panel */
.accordion {
  background-color: #eee;
  color: #444;
  cursor: pointer;
  padding: 18px;
  width: 100%;
  text-align: left;
  border: none;
  outline: none;
  transition: 0.4s;

  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: space-between;
  font-size: 1.8rem;
}

/* Add a background color to the button if it is clicked on (add the .active class with JS), and when you move the mouse over it (hover) */
.active, .accordion:hover {
  background-color: #ccc;
}

/* Style the accordion panel. Note: hidden by default */
.panel {
  padding: 0 18px;
  background-color: white;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.2s ease-out;
}

.accordion:after {
  content: '\02795'; /* Unicode character for "plus" sign (+) */
  font-size: 20px;
  color: #777;
  float: right;
  margin-left: 5px;
}

.active:after {
  content: "\2796"; /* Unicode character for "minus" sign (-) */
}
</style>

<button class="accordion">Section 1</button>
<div class="panel">
<p>
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
</p>
</div>
<button class="accordion">Section 2</button>
<div class="panel">
<p>
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
</p>
</div>
<button class="accordion">Section 3</button>
<div class="panel">
<p>
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
</p>
</div>

<script>
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";
    }
  });
}
</script>