Hi
You can set the logo height and width by using this custom CSS
.logo-image {
height: 150px !important;
width:100% !important;
}
For changing the background color and size use this one
#sp-header-topbar{
height:200px !important;
background-color:#0dcaf0 !important
}
Mobile topbar hide use this
@media (max-width: 844px){
#sp-header-topbar{
display:none;
}
}
Path towards custom CSS: Extensions>Templates>Styles> Click on your current default template name then choose Template Options. Then find custom CSS within the custom code.