I updated this custom CSS:
/*Edit layout*/
.t4-edit-layout .t4-header .container {
padding-top: 1rem !important;
}
.t4-edit-layout #t4-header {
background: #212529 !important;
}
.t4-edit-layout .t4-header {
background-color: inherit !important;
border-bottom: unset !important;
}
Kindly check.