I tried this in Codepen:

Html:

 <li id="menu-item-2952" class="fa fa-search menu-item  
 menu-item-type-post_type menu-item-object-page menu- 
item-2952"><a title="Search Adsler" 
href="https://adsler.co.uk/search-adsler/">Search 
Adsler</a></li>
</ul>
</li>
</ul></div>                         
</div>

Css:

.menu-item-2952 {background-color: red;} 

Works perfectly.

Tried it on my site, nothing

Also tried using important-nothing.

Tried also:

#menu-item-2952 {background-color: red;} 

This changes the color to green (which it is now) and red.

Tried:

#menu-item-2952 {background-color:  red! Important;} 

This does not nothing at all.

What I want is to change the background color from green to white.

2 Answers

-1
IvanS95 On Best Solutions

Inspecting you site, it seems you have the following rule:

.menu-item-2952 {
    background-color: white !important;
}

This will override any background color you want to specify due to the !important keyword; if possible, you should remove this rule from your CSS, or set your own class to:

.menu-item-2952 {
    background-color: red !important;
 }

EDIT: I notice now that, since you mentioned you want the background to be white, not green, it seems you are targeting the wrong element; the element that has the green background is actually the anchor tag, try instead to target that selector with your CSS and have something like:

a[href="https://adsler.co.uk/search-adsler/"]{
   background-color: white;
}

enter image description here

-1
Tim Hinz On

Change your CSS to:

#menu-item-2952 {background-color: red;} 
 <li id="menu-item-2952" class="fa fa-search menu-item  
 menu-item-type-post_type menu-item-object-page menu- 
item-2952"><a title="Search Adsler" 
href="https://adsler.co.uk/search-adsler/">Search 
Adsler</a></li>
</ul>
</li>
</ul></div>                         
</div>

Edit:

I didn't realize you just had a space in your html lol: You have menu- item-2952 change it to menu-item-2952. Or just use the ID like I said.

.menu-item-2952 {background-color: red;} 
 <li id="menu-item-2952" class="fa fa-search menu-item  
 menu-item-type-post_type menu-item-object-page menu-item-2952"><a title="Search Adsler" 
href="https://adsler.co.uk/search-adsler/">Search 
Adsler</a></li>
</ul>
</li>
</ul></div>                         
</div>