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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/paulmcauley/klassy/llms.txt

Use this file to discover all available pages before exploring further.

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Overview

Klassy provides extensive window decoration customization options, allowing you to fine-tune every aspect of your window appearance from titlebars to borders to shadows.

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Titlebar Settings

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Basic Appearance

Control how the window title appears:
  • Bold Title - Makes the window title text bold (default: enabled)
  • Underline Title - Adds an underline to the title text (default: disabled)
BoldTitle=true
UnderlineTitle=false

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Titlebar Opacity

Control transparency of active and inactive window titlebars: 
ActiveTitleBarOpacity=100    # 0-100%
InactiveTitleBarOpacity=100  # 0-100%
Special Options:
Forces maximized windows to have fully opaque titlebars, regardless of the opacity setting.
OpaqueMaximizedTitleBars=true
Why use this? Transparency on maximized windows can sometimes interfere with content readability. This option ensures maximized windows always have solid titlebars.
Applies a blur effect behind transparent titlebars.
BlurTransparentTitleBars=true
Requires: KWin blur effects to be enabled in System Settings
Extends opacity settings to the entire header area, not just the titlebar.
ApplyOpacityToHeader=true

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Titlebar Spacing

Alignment & Spacing screenshot Fine-tune titlebar margins and spacing:
Adjust vertical spacing:
TitleBarTopMargin=3.6        # 0-50
TitleBarBottomMargin=3.6     # 0-50
LockTitleBarTopBottomMargins=true
Enable the lock to maintain equal top and bottom margins automatically.

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Title Alignment

Choose how the window title is positioned:
  • AlignLeft - Title aligns to the left
  • AlignCenter - Title centers between buttons
  • AlignCenterFullWidth - Title centers across full titlebar width (default)
  • AlignRight - Title aligns to the right
TitleAlignment=AlignCenterFullWidth
TitleSidePadding=4  # Extra padding around title (0-60)

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Window Borders

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Corner Radius

Set the roundness of window corners: 
WindowCornerRadius=4.0  # 0-24.0
Higher values create more rounded corners. Set to 0 for sharp, square corners.
Additional Options:
  • Round All Corners When No Borders - Rounds all four corners when window borders are disabled 
    RoundAllCornersWhenNoBorders=true

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Border Colors

Control how window borders are colored:
  • Use Titlebar Color for All Borders - Matches border color to titlebar 
    UseTitleBarColorForAllBorders=true
  • Draw Border on Maximized Windows - Shows borders even when maximized 
    DrawBorderOnMaximizedWindows=false

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Window Outlines

Klassy offers configurable thin window outlines with accent colors: Thin window outline with accent

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Outline Thickness

WindowOutlineThickness=1.0          # 0.5-10.0
WindowOutlineSnapToWholePixel=true  # Crisp pixel rendering
WindowOutlineOverlap=true           # Overlap with window content

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Outline Styles

Choose outline style for active and inactive windows: 
WindowOutlineStyleActive=WindowOutlineShadowColor
Available styles:
  • WindowOutlineNone - No outline
  • WindowOutlineShadowColor - Uses shadow color (default)
  • WindowOutlineContrast - Automatic contrast color
  • WindowOutlineAccentColor - System accent color
  • WindowOutlineAccentWithContrast - Accent blended with contrast
  • WindowOutlineCustomColor - Custom color
  • WindowOutlineCustomWithContrast - Custom blended with contrast

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Outline Opacity

Fine-tune outline transparency for each style: 
WindowOutlineShadowColorOpacity=20              # 0-100%
WindowOutlineContrastOpacityActive=25           # 0-100%
WindowOutlineAccentColorOpacityActive=67        # 0-100%
WindowOutlineAccentWithContrastOpacityActive=50 # 0-100%

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Custom Outline Colors

When using custom outline styles: 
WindowOutlineCustomColorActive=0,0,0  # RGB color
WindowOutlineCustomColorOpacityActive=60
LockWindowOutlineCustomColorActiveInactive=true

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Colorize Window Outline with Button

Automatically color the window outline based on hovered button: 
ColorizeWindowOutlineWithButton=true
This creates a subtle visual connection between buttons and the window outline when hovering.

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Shadows

Configure drop shadows for windows:

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Shadow Size

Choose from predefined shadow sizes: 
ShadowSize=ShadowLarge
Available sizes:
  • ShadowNone - No shadow
  • ShadowSmall
  • ShadowMedium
  • ShadowLarge (default)
  • ShadowVeryLarge

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Shadow Strength

Adjust shadow intensity: 
ShadowStrength=255  # 25-255
Lower values create softer, more subtle shadows. Higher values create darker, more pronounced shadows.

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Shadow Color

Customize shadow color: 
ShadowColor=0,0,0  # RGB values
Black (0,0,0) is the most common shadow color, but you can use any RGB color for creative effects.

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Window-Specific Exceptions

Klassy allows you to create exceptions for specific applications or window types. This is configured through the Exceptions dialog in Klassy Settings.

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Exception Options

  • Hide Titlebar - When to hide the titlebar:
    • Never (default)
    • Always
    • Maximized
    • Any Maximization
    • Kept Behind
    • Any Maximization or Kept Behind
  • Opaque Titlebar - Force titlebar opacity for specific windows
  • Match Titlebar to Application Color - Per-window override
  • Prevent Apply Opacity to Header - Disable header opacity for specific apps
  • Custom Border Size - Override border size per application

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Matching Windows

Exceptions can match windows by:
  • Program Name Pattern - Regular expression matching executable name
  • Window Class Name - X11 window class
  • Window Title - Window title pattern
Exceptions are powerful but complex. Test your patterns carefully to ensure they match the intended windows.

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HiDPI Scaling

All spacing, sizing, and thickness values in Klassy automatically scale for HiDPI displays. You don’t need to adjust values manually for different DPI settings.

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Next Steps

Button Customization

Customize button appearance and behavior

Animations

Configure window decoration animations

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