In the old version of Yahoo e-mail, you accustomed us to the fact that unread messages have bold titles, and read messages have normal font titles. This is natural, since unread messages require greater attention, due to the fact that unknown information is not yet assimilated. Moreover, it is a matter of perception, in the idea that an unpressed button is more prominent (more visible) than a pressed one, which makes the bold font of unread messages welcome.
The confusing problem, however, is that in the new version you have reversed the system, with read messages being marked with a gray background, and unread ones with a white background. This, according to the reasoning above, is very confusing. Please analyze the situation, consulting with visual communication specialists, to make things as pleasant as possible, which is essential for a tool used daily by millions of people. A reasonable option could be to offer us the possibility to customize the appearance, not only by changing the theme or to dark mode, but also regarding the background of the message titles. With respect, Radu Ilea