Selecting elements for IE7 & IE8 in Custom CSS via class name does not work

Hello there, Thanks for the clean theme, I’m using it for business.

Here’s one issue I’ve found. I have Custom CSS (via a Plugin) and just want to be able to change styling for IE7 and IE8 in some places. Below is one such example and CSS like this works in the default WordPress theme like Twenty Thirteen.

.ie7 .site-header .site-title, .ie7 .site-header .site-title *,
.ie8 .site-header .site-title, .ie8 .site-header .site-title * {
color: gray; background-image: none;
}

The above example does not work with GovPress. Can this functionality be added or fixed?