[Theme Horse Support Team]

Hi Tomstrain,

To eliminate the space between the left sidebar and the main content first remove the CSS code that you have edited in the main style.css and Go to Appearance -> Theme Options/Customize -> Design Options Tab -> Custom CSS paste the following CSS code and Click on save all changes button:

#primary {
    width: 76%;
}
#secondary {
    width: 20%;
}
@media only screen and (max-width: 1078px) {
	#primary, #secondary {
	   width: 100%;
	}
}

Thank you!