Although there is no built-in dark mode for Gmail yet, there is a perfectly fine workaround. The increasing popularity of dark mode reached to a point where it is no more acceptable to have a web app or a website without available dark theme.
Dark mode can reduce eye strain, allow you to be more productive, and, most importantly, give you another layer of protection for your eyes. As we are spending more and more time in front of the screen, our eyes suffer the most out of this. Obviously, there is no turning back; we will be spending most of our waking hours staring at screens. Thus something must be done to lift the heavy burden we are putting on our eyesight.
The fact is that we are sending more and more emails, and pretty much all communication is done via email. E-mail is one of those online activities that can literally eat up half of your day. This is why improving how you handle email is a good starting point to minimize the pressure you put on your eyes every day.
Preferred by the power users, dark mode is beneficial for pretty much everyone these days. It significantly reduces eye strain, especially if you work late at night or in a low-light environment. Some people simply cannot stay for more than 15 minutes in front of the screen without using dark mode due to sensitive eyes. Of course, the positive outcome for power users is far bigger, but it is mainly due to the large amount of time they spend bashing out emails.