Line Numbers Impossible To See in AdminCP Editor

[Serpius]

Open this css file:

admin/jscripts/codemirror/theme/mybb.css

and see at line no. 6 if it is there:

.cm-s-mybb .CodeMirror-linenumber { color: white; }

If not try adding it, if yes - append 'important'

.cm-s-mybb .CodeMirror-linenumber { color: white !important; }

If the issue still not resolved, open this css:

admin/jscripts/codemirror/lib/codemirror.css

Go to line no. 36:

.CodeMirror-linenumber {
 padding: 0 3px 0 5px;
 min-width: 20px;
 text-align: right;
 color: #999;
 white-space: nowrap;
}

Change the color to 'white'.

Thanks to @effone!

I had to append "!important" to get it to work properly.

Was the code originally done without the "!important" in it? Meaning, does that how it looks like when we get the install package?
I am curious because I am wondering if another AdminCP theme had removed "!important" from that line. 
Or a different AdminCP theme possibly replaced the mybb.css with its own copy, which would have not included the "!important" in that part of the code?