Adjust Disqus width to fit in your theme.

wp-disqus-width.css

#disqus_thread {
	padding: 12px 10px 0;
	margin: 0 auto;
	max-width: 800px;
}

@media screen and (min-width: 673px) {
	#disqus_thread {
		padding-left: 30px;
		padding-right: 30px;
	}
}

@media screen and (min-width: 1040px) {
	#disqus_thread {
		padding-left: 15px;
		padding-right: 15px;
	}
}

@media screen and (min-width: 1110px) {
	#disqus_thread {
		padding-left: 30px;
		padding-right: 30px;
	}
}