How to change the background color for bar widget?

Hi all,

I am using the Temperature meter bar example provided by lvgl (Bar (lv_bar) — LVGL documentation) lvgl the output is blue color background but my one is orange color may I know how to change the background color?

lv_obj_set_style_bg_color(bar, lv_palette_main(LV_PALETTE_RED), LV_PART_MAIN); - red background