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Automatic dark mode with OpenBSD and dwm
Hacking my way to smart color theme switching.
Things might be easier with a full desktop environment, but on BSD and Linux I tend to prefer just running a simple window manager like dwm. There are several tools dedicated to this, but I opted to use Redshift, which also adjusts the color temperature of your screen throughout the day to make it easier on the eyes. As a bonus, I recommend the excellent Stylus browser extension together with dark themes for Wikipedia, Stack Overflow, etc.
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