<style>
#main-header, #main-header .nav li ul, .et-search-form, #main-header .et_mobile_menu {
background-color: black !important;
}
<style>
<style>
#main-header, #main-header .nav li ul, .et-search-form, #main-header .et_mobile_menu {
background-color: black !important;
}
<style>