Custome theme

Hi ,

I am using two Buttons, and having issue in setting style to it 

        Button adminButton = new Button("Admin");
        adminButton.setIcon(VaadinIcons.USER);
        adminButton.setStyleName("borderless");

        Button logoutButton = new Button();
        logoutButton.setIcon(VaadinIcons.SIGN_OUT);
        logoutButton.setStyleName("logout ");

my css id as follows .

.v-button-borderless {
        color: #057cb1;
        font-weight: 600;
          .v-icon {
            color: #217ca6;
        }
          &:hover {
            color: #1e6e93;
            .v-icon {
                color: #1e6e93;
            }
        }
    }
    
      .v-button-logout {
        color: #057cb1;
        font-weight: 600;
        .v-icon {
            color: #ffffff;
        }
        &:hover {
            color: #1e6e93;
             .v-icon {
                color: #1e6e93;
            }
        }
    }

I want logoutButton icon to be white.
if i aply 'borderless ' to logoutButton and change v-icon{  color: #ffffff; } it will work .but i am using 'borderless ' style in other palce too so i dont want to modify it. so writting new style as 'logout' but it is not appling.

Thanks