Hi,
Please try adding below code at Appearance -> Customize -> Additional CSS. Make sure to change hex color code.
/*For top bar contact details*/
.top-right p, .top-right span, .row.top-bar i {
color: #000000;
}
/* For Top Bar background Color*/
.top-baar {
background-image: linear-gradient(to right, #00d39f, #008bd3, #d40063, #d4be00 );
}
Thanks