Issue double selector CSS input:not(:placeholder-shown)::before

Question

I'm trying to use two selector CSS but he doesn't work..

input:not(:placeholder-shown)::before {
            content: '';
            display: block;
            height: 80px;
            width: 80px;
            background-color: red;
        }

<span id="input_1_1_3_container" class="name_first">
    <input type="text" name="input_1.3" id="input_1_1_3" value="" aria-required="true" placeholder="Prénom">
                                                    
    <label for="input_1_1_3">Prénom*</label>
</span>

I dont' understand why when i write in the input ce before not appear.

Anyone have and idea why she does not work ? I search a long time ...