Wikia.css isn't used anymore. Use Common.css instead. You can also use Fandomdesktop.css. See the page "Help:CSS and JS customization".
$<span class="br0">(</span><span class="br0">(</span>$<span class="br0">(</span><span class="st0">'h1.wordmark'</span><span class="br0">)</span>.<span class="me1">length</span> <span class="sy0">?</span> <span class="st0">'h1.wordmark'</span> <span class="sy0">:</span> <span class="st0">'.wds-community-header__wordmark'</span><span class="br0">)</span> <span class="sy0">+</span> <span class="st0">' a img'</span><span class="br0">)</span>.<span class="me1">attr</span><span class="br0">(</span>
<span class="st0">'src'</span><span class="sy0">,</span>
images<span class="br0">[</span><span class="kw4">Math</span>.<span class="me1">floor</span><span class="br0">(</span><span class="kw4">Math</span>.<span class="me1">random</span><span class="br0">(</span><span class="br0">)</span> <span class="sy0">*</span> images.<span class="me1">length</span><span class="br0">)</span><span class="br0">]</span>
<span class="br0">)</span><span class="sy0">;</span></div></div>
'h1.wordmark a img'<p>To this: </p>
'h2.wordmark a img'
style="background:transparent; color:transparent; border:0;"
</p><p>But since you can't edit the tabs directly, you'd need to put the tabber in a container with a class indicating which tab is hidden, then use CSS to apply the styling. Or perhaps give hidden tabs a certain title format and use JS to find them and apply the style.
</p><p>Not sure what the use in hiding a tab is though, it's not really wiki-like.
</p>
$.<span class="me1">getJSON</span><span class="br0">(</span><span class="st0">'/api.php?action=parse&prop=wikitext&page=Sidebar Navigation&format=json'</span><span class="sy0">,</span> <span class="kw1">function</span> <span class="br0">(</span>data<span class="br0">)</span> <span class="br0">{</span>
data <span class="sy0">=</span> data.<span class="me1">parse</span>.<span class="me1">wikitext</span><span class="br0">[</span><span class="st0">'*'</span><span class="br0">]</span><span class="sy0">;</span>
$<span class="br0">(</span><span class="st0">'.WikiaActivityModule'</span><span class="br0">)</span>.<span class="me1">after</span><span class="br0">(</span>data<span class="br0">)</span><span class="sy0">;</span>
<span class="br0">}</span><span class="br0">)</span><span class="sy0">;</span></div></div>
<p>That's a little different from the normal use case since you're storing the HTML on the page, but I got that code to work. Much easier than your current code :P.
</p>