input.css

.is-guest {
  & #header-panel-bar {
    & #chat-button {
      width: 33%;
      & span {
        display: none;
      }
    }
    & #users-button {
      left: 33%;
      width: 34%;
    }
    & #waitlist-button {
      left: 67%;
      width: 33%;
    }
    & #friends-button {
      display: none;
    }
  }
  & #user-lists {
    /* even the staff button doesn't work for guest users! */
    @nest & .button.staff, & .button.ignored {
      display: none;
    }
  }
  & #footer-user {
    & .signup {
      width: 40%;
    }
    & .signup.login {
      margin-left: calc(40% + 1px);
      width: calc(40% - 1px);
      background: #555d70;
    }
    & .buttons {
      display: block;
      & .button {
        display: none;
      }
      & .button.extplug-guest-settings {
        display: block;
        margin-left: 80%;
      }
    }
  }
  & #user-menu .item:not(.settings):not(.extplug-plugins) {
    display: none;
  }
  & #room-bar {
    & .extplug-room-bar-overlay {
      height: inherit;
      width: inherit;
      position: absolute;
      z-index: 10;
    }
  }
}

output.css

.is-guest #header-panel-bar #friends-button {
      display: none;
}
.is-guest #header-panel-bar #waitlist-button {
      left: 67%;
      width: 33%;
}
.is-guest #header-panel-bar #users-button {
      left: 33%;
      width: 34%;
}
.is-guest #room-bar {
    & .extplug-room-bar-overlay {
      height: inherit;
      width: inherit;
      position: absolute;
      z-index: 10;
    }
}
.is-guest #user-menu .item:not(.settings):not(.extplug-plugins) {
    display: none;
}
.is-guest #footer-user {
    & .signup {
      width: 40%;
    }
    & .signup.login {
      margin-left: calc(40% + 1px);
      width: calc(40% - 1px);
      background: #555d70;
    }
    & .buttons {
      display: block;
      & .button {
        display: none;
      }
      & .button.extplug-guest-settings {
        display: block;
        margin-left: 80%;
      }
    }
}
.is-guest #user-lists {
    /* even the staff button doesn't work for guest users! */
    @nest & .button.staff, & .button.ignored {
      display: none;
    }
}.is-guest {
}
.is-guest #header-panel-bar {
}
.is-guest #header-panel-bar #chat-button {
      width: 33%;
}
.is-guest #header-panel-bar #chat-button span {
        display: none;
}