ruler visibility

My old eyes have difficulty with visibility of the rulers in Writer. The font is too small and pale. Is there a way to adjust the size (height or width) of the rulers and to change the color and size of the numbers.
I notice in the expert configuration there are some settings for the rulers in the Windows Layout such as verticalruletunit long 8. What do those settings do? Can I use them to solve my problem?

Is there a high contrast mode in your operating system? Have a look for Accessibility in the settings for your operating system. You might also be able to increase the font size for menus, etc.

In Windows 10: Start Menu > Settings > Ease of Access then for size >Display > Make everything bigger or for high contrast > High Contrast > ON > Choose a theme try High Contrast white, the rules will then be black and white but then also so will your icons

If LO doesn’t change to high contrast when OS does then in the menu click Tools > Options > LibreOffice > Accessibility and tick the box “Automatically detect high contrast mode of operating system”