Font-size for the posts in "Aside" Format

Hi, great theme ! Thx for your work ! I'm looking for the line in the Style.css, to change the size of the text in the posts with the "Aside" format, I think it's too small… I found this :

.entry-header .entry-format {
	color: #666;
	font-size: 10px;
	font-weight: 500;
	letter-spacing: 0.1em;
	line-height: 2.6em;
	position: absolute;
	text-transform: uppercase;
	top: 0;
	right: 5px;
}

When I change font-size:10px with 12px, nothing happens… Thx for your help… Emi