HTML/CSS How to apply CSS to "a" with custom data attribute?

I already know how to apply CSS to custom data attributes but in my case it just doesn't seem to work. I don't want to select by class but by data-store attribute.

HTML

<a class="hello" data-store="{&quot;dialogURI&quot;:&quot;\/messages\/compose\/dialog\/&quot;}" href="#" role="button" rel="dialog"></a>

CSS

[data-store=" {"dialogURI":"\/messages\/compose\/dialog\/"}"]{
position:fixed!important;
bottom:0px!important;
}

But it doesn't seem to work. Any help would be greatly appreciated.