Hey ,

You can use the below css selectors to make the changes you need. The below sets the background from white to transparent .

Add this into the Custom CSS box located in your Salient Options panel (Make Sure there are no red cross in the Box) :

#crm-container.crm-public input[type="text"], #crm-container.crm-public input[type="password"], #crm-container.crm-public input[type="email"], #crm-container.crm-public select {
    background: transparent !important;
}
.crm-container.crm-public .select2-container .select2-choice {
    background: transparent !important;
}

Thanks