Dark mode is inconsistently supported. Some sites have it; most don't. The ones that do require three clicks to find. The ones that don't leave you staring at a white background at 11pm.
NightOwl fixes this by applying dark mode everywhere, automatically.
What NightOwl does
NightOwl is a Firefox extension that enables dark mode on every website. You don't configure anything. Install it, and every site you open gets a dark theme — including sites that have never added dark mode support.
It also auto-schedules by sunset and sunrise. When the sun sets, dark mode turns on. When it rises, it turns off. It uses your location's local time, not a fixed clock.
Why browser dark mode isn't enough
Firefox has a "dark mode" preference that hints to websites that the user prefers dark themes. But this only works if the website actually supports prefers-color-scheme. Most sites don't. You tell Firefox "dark mode" and 70% of the web ignores it.
NightOwl doesn't hint. It applies a dark transformation directly. The site doesn't need to support anything.
What about CSS injection approaches
Most dark mode extensions inject CSS overrides. The result is inconsistent — some elements flip correctly, others end up white-on-white or black-on-black. Getting it right requires per-site tuning.
NightOwl uses a different approach. The transformation is applied at the rendering layer, which means it works on new sites without manual tuning.
The scheduling logic
Sunrise and sunset times change every day and vary by location. NightOwl calculates both automatically from your geographic coordinates (which Firefox provides locally — nothing leaves the browser). No clock to manually set, no timezone confusion. Dark mode is off during daylight and on after sunset.
You can also override manually if the schedule doesn't match your preference for a given session.
Install it
Free. No account. Works in Firefox.
This is one of 11 Firefox extensions I built — all free, no-account, no-server. See the full series for the others.
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