Hi there,
Currently, those styling are being overridden by Charm template. You will need to do some tweaks on your custom css files in order to achieve this.
Can you try css code below and see how it goes. Change those colour accordingly. Remember to enable this setting
https://take.ms/vhexD once you applied those changes. Once saved, disabled them again.
[gist type="css"]
#es.mod-es.mod-es-toolbar .es-toolbar {
background-color: #4104e4 !important;
}
#es.mod-es.mod-es-toolbar .es-toolbar:before, #es.mod-es.mod-es-toolbar .es-toolbar:after {
background-color: #4104e4 !important;
}
#es.mod-es.mod-es-toolbar .es-toolbar:before, #es.mod-es.mod-es-toolbar .es-toolbar:after {
background-color: #4104e4 !important;
}
[/gist]