themes – What’s the default order used by WordPress to load CSS files?

I am working with a commercial theme on which I am making some style changes. Specifically, the parent theme shows a menu which I want to modify. The code for that menu is:

 <div class="mobile-navigation hidden-md hidden-lg">
        <div id="close-menu-moblie">
            <a href="#">
                <i class="icon-close icons"></i>
   <div class="mobile-menu-container">
        <ul id="menu-menu-movil" class="nav-menu mobile-menu">
            <li id="menu-item-4723" class="menu-item menu-item-type-custom menu-item-object-custom current-menu-item current_page_item menu-item-4723 active">
                <a href="/" aria-current="page">La Familia</a>
            <li id="menu-item-4724" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-4724">
                <a href="">La Tierra</a>

So I created a child theme and added some CSS to it in its style.css file:

#menu-menu-movil li > a {
    font-weight: 500;
    font-family: Poppins, Arial, sans-serif;

No way: the site ignores my changes. When I inspect the HTML I see that the browser is applying instead CSS instructions from the parent theme that target different classes:

.mobile-navigation .nav-menu > li > a {
    font-size: 16px;
    color: #1a1a1a;
    font-weight: bold;
    text-transform: capitalize;

So I think that it’s a problem with conflicting CSS instructions and their level of specificity or whatever… but then I try opening the CSS editor in WP Admin at “Appearance / Customise / Additional CSS” and pasting there my changes… and they work.

This led me to think: is there a default order in which WordPress loads CSS from all the possible places where they can be? (“Additional CSS”, child themes, parent themes…). I seem to remember that there was, but after searching around on Google for a while I couldn’t find anything. Or is my problem in the end about CSS specificity?