Layerが切り替わったら背面LEDの色も変える

keymap.c

uint32_t layer_state_set_user(uint32_t state) {

    uint8_t layer = biton32(state);

    ergodox_board_led_off();
    ergodox_right_led_1_off();
    ergodox_right_led_2_off();
    ergodox_right_led_3_off();
    switch (layer) {
      case 0:
#ifdef RGBLIGHT_COLOR_LAYER_0
          rgblight_setrgb(RGBLIGHT_COLOR_LAYER_0);
#endif
#ifdef RGBLIGHT_ENABLE
          rgblight_enable();
          rgblight_mode(1);
          rgblight_setrgb(0x00,0x00,0x00);
#endif
        break;
      case 1:
        ergodox_right_led_1_on();
        #ifdef RGBLIGHT_COLOR_LAYER_1
          rgblight_setrgb(RGBLIGHT_COLOR_LAYER_1);
        #endif
#ifdef RGBLIGHT_ENABLE
          rgblight_enable();
          rgblight_mode(1);
          rgblight_setrgb(0xff,0x00,0x00);
#endif
        break;
      case 2:
        ergodox_right_led_2_on();
        #ifdef RGBLIGHT_COLOR_LAYER_2
          rgblight_setrgb(RGBLIGHT_COLOR_LAYER_2);
        #endif
#ifdef RGBLIGHT_ENABLE
          rgblight_enable();
          rgblight_mode(1);
          rgblight_setrgb(0x00,0xff,0x00);
#endif
        break;
        .....