CSS arrows

div.accordion-heading div.arrow {
    width: 0px;
    height: 0px;
    border: 10px solid transparent;
}

div.accordion-section.active div.arrow {
    border-top: 15px solid #28f;
    border-left: 10px solid transparent;
    margin-left: 20px;
    margin-top: 43px;
}

div.accordion-heading div.arrow {
    border-left: 15px solid #28f;
    border-top: 10px solid transparent;
    margin-left: 24px;
    margin-top: 40px;
}

<div class="accordion-heading">
    <div class="arrow"></div>
</div>