Change Mobile Menu Background Color

#1. Add this code to Custom CSS box and Save

/* Mobile menu background color */
.header-menu-bg.theme-bg--primary {
    background-color: #f1f !important;
}

#2. You will have a result like this

Change Mobile Menu Background Image

#1. Add this code to Custom CSS box and Save (you can change example image url to url what you want)

/* Mobile menu background color */
.header-menu-bg.theme-bg--primary {
    background-image: url(https://cdn.pixabay.com/photo/2024/01/07/14/12/man-8493244_1280.jpg);
}

#3. You will have a result like this