How to remove or change theme

Description

Hi
I want to change theme in lvgl.
For example I am using line meter when I set the higher value it showing red indicators.
When I create a button the border is showing in red color.
So I want to change theme or disable it.

What MCU/Processor/Board and compiler are you using?

ARM

What LVGL version are you using?

v7

What do you want to achieve?

I want to change theme in lvgl

What have you tried so far?

Code to reproduce

Add a code snippet which can run in the simulator. It should contain only the relevant code that compiles without errors when separated from your main code base.

The code block(s) should be formatted like:

/*You code here*/

Screenshot and/or video

If possible, add screenshots and/or videos about the current state.

To change which theme is in use, you can edit the settings in lv_conf.h (example). Alternatively, you can customize the theme itself by editing the source file.