div#page div {
margin-left: 10px !important;
max-width: 90% !important;
}
I’m not very knowledgeable in css, but that sure seems to be the page, not the listing map widget itself. I’m really hoping I have better luck with you in trying to find the selector to change the width for the small map.
I actually think you should delete the div#page div selector. It seems to be doing more harm than good. I disabled the styles in the selector via the Firebug CSS inspector and discovered that your map fills the width of it’s container:
(see how I’ve disabled the styles in the bottom right of the screenshot)
But did you want the map to be bigger still?
Cheers,
Sebastian
ps I suspect that this issue may need some attention on the Javascript side of things rather than the CSS/Microthemer side of things.