accordion
<dl class="accordion">
<dt>title 1</dt>
<dd>contents 1 ...</dd>
<dt>title 2</dt>
<dd>contents 2 ...</dd>
<dt>title 3</dt>
<dd>contents 3 ...</dd>
</dl>
$('.accordion dd').hide();
$('.accordion dt').css('cursor', 'pointer').on('click', function() {
// $('.accordion dt').removeClass('is-open');
// $('.accordion dd').stop().slideUp();
$(this).toggleClass('is-open');
$(this).next().stop().slideToggle();
});