Module system 

Discovers system-native styling for colors, fonts, and other metrics.

This module provides a best-effort attempt to query the host operating system for its UI theme information. This is gated behind the io feature flag.

Application-Specific Ricing: By default (if the io feature is enabled), Azul will look for an application-specific stylesheet at ~/.config/azul/styles/<app_name>.css (or %APPDATA%\azul\styles\<app_name>.css on Windows). This allows end-users to override and “rice” any Azul application. This behavior can be disabled by setting the AZUL_DISABLE_RICING environment variable.

Linux Customization Easter Egg: Linux users can set the AZUL_SMOKE_AND_MIRRORS environment variable to force Azul to skip standard GNOME/KDE detection and prioritize discovery methods for “riced” desktops (like parsing Hyprland configs or pywal caches), leaning into the car “ricing” subculture where a flashy appearance is paramount.

Modules

apple_fonts

Apple system font family names for font fallback chains.

defaults

A collection of hard-coded system style defaults that mimic the appearance of various operating systems and desktop environments. These are used as a fallback when the “io” feature is disabled, ensuring deterministic styles for testing and environments where system calls are not desired.

linux_fonts

Linux/GTK common font family names.

windows_fonts

Windows system font family names.

Structs

AccessibilitySettings

Accessibility settings detected from the operating system.

AnimationMetrics

Animation-related preferences from the OS.

AudioMetrics

Audio-feedback preferences from the OS.

FocusVisuals

Focus ring / indicator visual style.

IconStyleOptions

Icon-specific styling options for accessibility and theming.

InputMetrics

Input interaction timing and distance thresholds from the OS.

LinuxCustomization

Linux-specific customisation settings.

SafeAreaInsets

Safe area insets for devices with notches, rounded corners, or sensor housings.

ScrollbarPreferences

OS-level scrollbar behaviour preferences.

SystemColors

Common system colors used for UI elements.

SystemFonts

Common system font settings.

SystemMetrics

Common system metrics for UI element sizing and spacing.

SystemStyle

A unified collection of discovered system style properties.

TextRenderingHints

Text rendering configuration from the OS.

TitlebarButtons

Which window control buttons are available in the titlebar.

TitlebarMetrics

Metrics for titlebar layout and window chrome.

VisualHints

Visual hints from the OS about how icons and decorations should be shown.

Enums

DesktopEnvironment

Represents the detected Linux Desktop Environment.

FocusBehavior

Focus indicator behaviour (always visible vs keyboard-only).

Platform

Represents the detected platform.

ScrollbarTrackClick

What happens when clicking the scrollbar track area.

ScrollbarVisibility

When scrollbars should be shown (OS-level preference).

SubpixelType

Subpixel rendering layout for font smoothing.

SystemFontType

System font types that can be resolved at runtime based on OS settings.

Theme

The overall theme type.

TitlebarButtonSide

Which side of the titlebar the window control buttons are on.

ToolbarStyle

Toolbar display style (icons, text, or both).

Functions

detect_linux_desktop_env

Detect Linux desktop environment from environment variables

detect_system_language

Detect the system language and return a BCP 47 language tag. Falls back to “en-US” if detection fails.