position galley close "x" at bottom of the page

Site URL: http://thinknz.nz

Hi all,  I'm currently working on our new website, in the Wexley template, and am  trying to get the gallery close button (x) at the bottom of the page - ideally I'd like it just to the right of the prev/next navigation.

I have code that allows me to move the "x", and that's fine, but I can't get it to be relative to the bottom of the page.

Any suggestions?  

the code I'm using is

#backToThumbs:after {
 content: "x";
 color: #000;
}
.collection-type-gallery.full-view #backToThumbs {
 font-size: 3.0em;
 top: 100px;
right: 145px;
 color: rgba(0,0,0,0);
}
 

thanks in advance

.collection-type-gallery.full-view #backToThumbs {
    bottom: 0 !important;
    top: unset !important;
}
.site-alignment-center #header {
    position: static;
}
div#headerWrapper {
    position: static;
}
div#canvas {
    position: relative;
}

wow, thank you tuanphan.  That gave me the perfect direction - a little tweak and its all good. 

Plus, I learnt a couple of things so its  been able to help me sort another challenge.

again, thanks, very much appreciated.

cheers

Jeff