CSS Editor Plugin Removing CSS

We are running Omeka v.2.3 and installed the CSS Editor Plugin to customize CSS for a simple page. We have images which you will hover over to view text and the goal was to darken the image when you hover over it (see this site: http://geekgirllife.com/place-text-over-images-on-hover-without-javascript/.

When we add the CSS to the editor, it removes two lines, which should appear within `span.text-content {
background: rgba(0,0,0,0.5);
cursor: pointer;`
[color: white; is between these two and Omeka keeps this]

All the other lines appear. See below for the code.
Is there a way to change a setting in Omeka so that it does not delete/remove these lines? The images won't darken during hover without them.

ul.img-list {
list-style-type:none;
margin:0;
padding:0;
text-align:center
}

ul.img-list li {
display:inline-block;
height:250px;
margin:1em 1em 1em 0;
position:relative;
width:128px
}

span.text-content {
color:#fff;
display:table;
height:260px;
left:0;
position:absolute;
top:0;
width:150px;
opacity:0
}

span.text-content span {
display:table-cell;
text-align:center;
vertical-align:middle
}

ul.img-list li:hover span.text-content {
opacity:1
}

Thanks!

We have the settings for the CSS Editor pretty wide open, but these look like features that the underlying tools we use aren't designed to handle.

Since it sounds like you have your own installation, though, you could always add it directly, either in the theme's CSS or in the header.php file or whereever you need it.

Thanks, Patrick. I was able to figure out a workaround with a few different lines of code than what the tutorial listed.

Thanks!
Anna