CSS Signal Consistency

CSS features can leak platform and hardware information. BotBrowser normalizes these signals for consistent privacy protection.

Prerequisites

Familiarity with Browser Fingerprinting Explained.
BotBrowser installed with a valid profile. See Installation.

Quick Start


chromium-browser \
  --bot-profile="/path/to/profile.enc"

Start with this launch to establish a clean baseline before adding extra overrides.

Overview

CSS provides several mechanisms that reveal information about the user’s operating system, display hardware, and browser configuration. Media queries, @supports rules, system colors, and CSS function behavior all contribute platform-specific signals. BotBrowser normalizes all of these at the browser engine level so that reported values match the loaded profile, regardless of the host system.

Configuration

Color Scheme

Control the reported color scheme:


--bot-config-color-scheme=light
--bot-config-color-scheme=dark

Font System

The font configuration controls how system font keywords resolve:


# Profile fonts (system-ui maps to profile's platform font)
--bot-config-fonts=profile
 
# Real system fonts (no protection)
--bot-config-fonts=real

Display Properties

Screen and display characteristics are controlled through profile configuration:


# Use profile-defined screen properties (color depth, dimensions)
--bot-config-screen=profile

How BotBrowser Normalizes These Signals

BotBrowser normalizes all CSS-related signals at the browser engine level. Color scheme, feature availability, rendering behavior, and system colors all match the profile’s declared platform regardless of the host OS.

Common Scenarios

Capture a baseline result using the Quick Start setup.
Change one relevant setting at a time and compare the new output.
Keep your final launch command documented so future checks are reproducible.

Troubleshooting / FAQ

Problem	Solution
System font renders as host OS font	Verify `--bot-config-fonts=profile` is set.
Color scheme doesn’t match expectation	Set explicitly with `--bot-config-color-scheme=light` or `dark`.
@supports query reveals wrong platform	Check that the profile matches your intended platform. Feature availability follows the profile.
CSS system colors expose host theme	Ensure profile is loaded. System colors are controlled at the engine level.

Next Steps

Font Fingerprinting. Deeper coverage of font-based tracking.
Screen and Window Fingerprinting. Display properties as fingerprint surfaces.
Navigator Properties. JavaScript API surfaces that complement CSS signals.
Browser Fingerprinting Explained. The full fingerprinting landscape.

Related documentation: Advanced Features | CLI Flags Reference

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