fields with no white background

Hi, @aminoxer!

Add to your custom field this class:
class="form-control"

How did you add this field?

Can you give the URL of the registration page of your site?

Add this code to Additional CSS in Customizer:

[for="confirm_password"] {
    width: 100%;
}
#confirm_password {
    display: block;
    width: 100%;
   height: 34px;
   padding: 6px 12px;
   font-size: 14px;
   line-height: 1.428571429;
   color: #555;
   background-color: #fff;
   background-image: none;
   border: 1px solid var(--form-conrols-border-color);
   border-radius: 2px;
   box-shadow: inset 0 1px 1px rgba(0,0,0,.075);
   transition: border-color ease-in-out .15s,box-shadow ease-in-out .15s;
   margin-top: 8px;
}
#confirm_password:focus {
    box-shadow: inset 0 1px 1px rgba(0,0,0,.075),0 0 8px var(--form-conrols-box-shadow);
   outline: 0;
   border-color: var(--form-conrols-box-shadow);
}