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Feature
How System Sync Works
One switch and your browser's dark mode mirrors your operating system — no schedules to set, nothing to manage.
Follows OS Theme
When your system switches to dark mode, every website follows. When it switches back to light, they follow that too.
Automatic Day/Night
Combined with your OS's auto theme switching, you get dark websites at night and light ones by day — hands-free.
Your Colors Either Way
Night Mode uses your custom theme colors, so 'system dark' still looks like your dark mode.
Every Website
System sync applies across the whole web — no per-site toggles required.
Manual Override Anytime
Prefer a fixed schedule or always-dark? The schedule and manual toggle are still there when you want them.
Fully Private
Theme detection happens locally in the browser — nothing about your settings leaves your machine.
Why Sync Dark Mode With the System?
macOS, Windows, and most Linux desktops can switch between light and dark automatically — on a schedule or at sunrise and sunset. Apps that respect the setting feel native; websites that stay blindingly white at midnight break the illusion. System sync closes that gap.
One Setting, Whole Web
Enable the system-follow option in Turn Off the Lights Options → Night Mode, and your dark theme tracks the OS in every tab and on every site. It's the set-it-and-forget-it alternative to the built-in time-based schedule.
Works With Your Custom Theme
Following the system doesn't mean accepting a generic grey — when dark is active, Night Mode still applies your chosen background, text, and link colors.
Open Source, Private, and Free — Always
Turn Off the Lights collects no personal data, displays no advertising, and charges nothing. The extension is fully open-source under the GNU General Public License Version 2 (GPLv2), with its complete source code available on GitHub for anyone to inspect. It has been in continuous development since 2009 and remains one of the most trusted browser extensions available, with millions of active users across all major browsers. Stefan Van Damme is the solo developer and has maintained the extension with monthly updates for over 15 years.
How It Works
Get Dark Mode Everywhere in Under 30 Seconds
Turn Off the Lights is available in every major browser store and takes less than 30 seconds to install and activate. No configuration needed — it works instantly.
Install Turn Off the Lights
Add the free extension from your browser's store — Chrome, Firefox, Edge, Safari, or Opera.
Enable Night Mode
Open Turn Off the Lights Options → Night Mode tab and enable the Night Mode switch.
Customize Your Dark Theme
Pick your background, text, and link colors — or set an automatic schedule. Every website now loads dark.
FAQ
FAQ — System Dark Mode Sync
Yes — Turn Off the Lights can follow your system's dark/light setting, so websites go dark whenever macOS, Windows, or Linux does.
Yes — if your OS auto-switches themes, websites follow the same transitions automatically.
Yes — system sync controls when Night Mode is active; your custom colors control how it looks.
Yes — completely free and open-source, with no ads, no tracking, and no account required.
Dark Mode Guides
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