White text invisible on titles

Hi,
white text on coloured banner is often invisible, depending on which device I'm using.

Would it be possible to have black (or blue) text as a default so that the title of the topic is always visible regardless of whether your device is displaying the coloured backgrounds as intended?

Here the topmost thread looks blank on my laptop. The sticky "Tomato" thread title is visible, but using my phone, it looks blank.

Laptop:



Phone:



Thanks!