How to give a NavWalker its own stylesheet?
Walkers don’t have associated stylesheets. That’s not how they work. You need to load them separately by enqueuing the stylesheet in the wp_enqueue_scripts hook, as you’ve done in load_css(). The walker class gets used by setting the walker argument of wp_nav_menu() to an instance of the class when you’re rendering the menu in a template. … Read more