javascript - jquery plugin conflict with transform: translateY -

im using lightweight jquery plugin call leanmodal

the code plugin included in jsfiddle: https://jsfiddle.net/meqtu354/2/

all plugin is, example in jsfiddle, when u click on click show popup, pop show , rest of document covered huge dark transparent div.

but reason when add: transform: translatey css

now when click click show popup, overlay (dark transparent div) cover popup too.

i been reading half hour now, still cant figure out why

you need put popup div outside of st-scroll class:

<div id="popup">popup</div>  <div class="st-scroll">      <section></section>     <script></script>     <section></section>  </div>

i tried in fiddle , worked. when apply 3d transform property, think merges div if 1 object without layers.

Arrya Code