Change Test High or change Font of an Label

What i want to do is very simple (not for me i guess).
There is a Label and the Font on the Display is to Smal. Now i want to make it Bigger to be more readable. So far so fine.

I am Working with the 7.11 version on a Teensy 4.1, Arduino 1.8.19 /Tensiduino 1.56
My Code Buttons and Charts all working good.
he only problem i know is change/Copy a Style.
Why is it so complex to change a Test high ?

But i found some articles like this.

Now i am stuck !
I found some difrend Styles in lv_style.h but i am not shure wy they are not fund.

My try to copy a styl to mystile faild and i cant find wy.
My Code is very long so i post my error first here, because someone can help with that.

I get his error.

TFTMenu.h:3635: error: ‘lv_style_transp’ was not declared in this scope
lv_style_copy(&win_style, &lv_style_transp);

static lv_style_t win_style;   //definded in the Global

void (SetupTFT)
//init    snipset
  disp_drv.buffer = &disp_buf;

  /*Initialize the input device driver*/
  lv_indev_drv_t indev_drv;
  lv_indev_drv_init(&indev_drv);             /*Descriptor of a input device driver*/
  indev_drv.type = LV_INDEV_TYPE_POINTER;    /*Touch pad is a pointer-like device*/
  indev_drv.read_cb = my_touchpad_read;      /*Set your driver function*/
  lv_indev_drv_register(&indev_drv);         /*Finally register the driver*/

  //Set the theme..

 lv_style_copy(&win_style, &lv_style_transp);
//style.text.color = LV_COLOR_BLUE;
//style.text.font = &lv_font_dejavu_40; //Unicode and symbol fonts already assigned by the library/

// Anzeige FC
label_TimeAnzeige  = lv_label_create(scr_FClock, NULL);
    lv_label_set_text (label_Timeanzteige, "00:00");
    lv_obj_align(label_Timeanzteige, scr_FClock,LV_ALIGN_IN_TOP_MID, 100 ,100);

I think i miss some include ?
Tanks for try to help me
Greedings Jake

PS: I tryed 8.xx but it seems to be so diffrend that i stay at 7.11 this time untill my TFT Part is working well.

If you need to change only one property of text you can use local style. In this case you need to change text font

lv_obj_set_style_local_text_font(label_Timeanzteige, LV_LABEL_PART_MAIN, LV_STATE_DEFAULT, lv_theme_get_font_small());

Also replace lv_theme_get_font_small() with lv_theme_get_font_normal/lv_theme_get_font_subtitle/lv_theme_get_font_title in dependence of font you want use.

Thanks that worked for me.
greedings Jake