Dark Mode and Dark Dimmed line Visibility

The contrast is too low on many frame like displays and therefore some ease of navigation is lost. There are lines that separate different regions on display. This lines tend to be not visible in dark mode and somewhat visible in dark dim. Those lines provide a visual to estimate recognition. That is very useful on pages not explored very often.
Please have dark mode and dark dimmed intensive those subtle lines so that they stand out in those modes.