There will always be some users who want to view your content or product in dark Mode. When you do not have a custom CSS setup, you will need to make some updates in order to accommodate this user preference. Great designers may even welcome this new challenge for their coding techniques. Some website developers balk at having to redesign an entire website for the small number of users who want to do everything incognito. However, it is a reality that environmental variables will soon be a thing, and a site that does not perform well in different browser modes may be passed by in lieu of another one that does. Corporate clients may have legacy systems that do not run on the current or even a couple of past generations of browsers such as Internet Explorer. If the website cannot support it, or if it still uses a single sign-on technology such as SAML, then it may also have difficulty operating in dark web mode. On the other hand, a company that does not care enough about having its website work on Internet Explorer versions six to eight may also not care too much about being dark mode-compatible. Another concern that developers might run into is making an app dark mode-compatible. For example, apps that were developed for Internet Explorer 6 might only work on that version of the browser. The cost of moving to another platform and redesigning an entire site may not be feasible or worthwhile to such companies. In that case, they may have to deal with the reality that their sites might not be fully functional in dark mode. In theory, most users should be able to see the core content of a site in dark mode. Even a user who has a computer still chugging along on an old version of Windows and an old internet browser should still have some level of readable content. A company and developer would have to do the cost and benefit analysis of converting a few dozen visitors per month against the cost of redesigning the whole site. For more information click here https://stuffandnonsense.co.uk/blog/redesigning-your-product-and-website-for-dark-mode.