Marcus Sidecar Create Theme

Create Theme

Configuration Location

Themes are configured in ~/.config/sidecar/config.json:

{
  "ui": {
    "showFooter": true,
    "showClock": true,
    "nerdFontsEnabled": false,
    "theme": {
      "name": "default",
      "overrides": {
        "primary": "#FF5500",
        "success": "#00FF00"
      }
    }
  }
}

Available Base Themes

• default - Dark theme with purple/blue accents
• dracula - Dracula-inspired dark theme with vibrant colors
• molokai - Vibrant, high-contrast dark theme
• nord - Arctic, north-bluish color palette
• solarized-dark - Precision color scheme for reduced blue light
• tokyo-night - Clean dark theme celebrating Downtown Tokyo

Creating a Custom Theme

Method 1: Override Specific Colors

Start from a base theme and override specific colors:

{
  "ui": {
    "theme": {
      "name": "default",
      "overrides": {
        "primary": "#E91E63",
        "success": "#4CAF50",
        "error": "#F44336",
        "syntaxTheme": "github"
      }
    }
  }
}

Method 2: Full Theme Override

Override all colors for complete control. See references/palette-reference.md for every available color key and their default values across themes.

Method 3: Custom Gradient Borders

Panel borders support angled gradients (default 30 degrees) flowing diagonally:

{
  "ui": {
    "theme": {
      "overrides": {
        "gradientBorderActive": ["#FF0000", "#FF7F00", "#FFFF00", "#00FF00", "#0000FF", "#8B00FF"],
        "gradientBorderAngle": 45
      }
    }
  }
}

Gradients support 2+ color stops. If not specified, solid borderActive/borderNormal colors are fallback.

Tab Styles

Configure with tabStyle and tabColors in overrides:

Tab Styles:

• gradient - Colors flow continuously across all tabs (per-character interpolation)
• per-tab - Each tab gets a distinct solid color from array (cycles)
• solid - Uses theme primary/tertiary colors
• minimal - No background, active tab uses underline

Built-in Presets (use as tabStyle value):

• rainbow - Red -> Green -> Blue -> Purple (gradient)
• sunset - Orange -> Peach -> Pink (gradient)
• ocean - Deep Blue -> Cyan -> Light Blue (gradient)
• aurora - Purple -> Dark Purple -> Teal (gradient)
• neon - Magenta -> Cyan -> Green (gradient)
• fire - Red-Orange -> Orange -> Gold (gradient)
• forest - Dark Green -> Mid Green -> Light Green (gradient)
• candy - Pink -> Purple -> Turquoise (gradient)
• pastel - Pink, Green, Blue, Yellow (per-tab)
• jewel - Ruby, Sapphire, Amethyst, Topaz (per-tab)
• terminal - Red, Green, Cyan, Yellow (per-tab)
• mono - Theme primary color (solid)
• accent - Theme accent color (solid)
• underline - No background, underlined active (minimal)
• dim - No background, dim inactive (minimal)

Examples:

// Use a preset
{ "overrides": { "tabStyle": "sunset" } }

// Custom gradient
{ "overrides": { "tabStyle": "gradient", "tabColors": ["#FF6B35", "#F7C59F", "#FF006E"] } }

// Per-tab distinct colors
{ "overrides": { "tabStyle": "per-tab", "tabColors": ["#FF5555", "#50FA7B", "#8BE9FD", "#F1FA8C"] } }

Color Key Categories

All colors use hex format (#RRGGBB). Key categories:

• Brand: primary, secondary, accent
• Status: success, warning, error, info
• Text: textPrimary, textSecondary, textMuted, textSubtle, textHighlight, textSelection, textInverse
• Background: bgPrimary, bgSecondary, bgTertiary, bgOverlay
• Border: borderNormal, borderActive, borderMuted
• Gradient border: gradientBorderActive, gradientBorderNormal (arrays), gradientBorderAngle (number)
• Tab: tabStyle, tabColors (array)
• Diff: diffAddFg, diffAddBg, diffRemoveFg, diffRemoveBg
• UI elements: buttonHover, tabTextInactive, link, toastSuccessText, toastErrorText
• Danger: dangerLight, dangerDark, dangerBright, dangerHover
• Blame age: blameAge1 through blameAge5
• Third-party: syntaxTheme (Chroma theme name), markdownTheme (dark/light)

Full color values for all themes: see references/palette-reference.md.

Syntax Themes

The syntaxTheme value can be any Chroma theme:

• monokai, dracula, github, github-dark, nord, onedark, solarized-dark, solarized-light, vs, vim

See Chroma Style Gallery for all options.

Color Validation

Colors must be valid hex in #RRGGBB format. Invalid colors are ignored.

• Valid: "#FF5500", "#ff5500" (lowercase ok)
• Invalid: "FF5500" (missing #), "#F50" (shorthand), "red" (named colors)

Nerd Fonts

When nerdFontsEnabled is true: pill-shaped tabs (Powerline chars), pill-shaped buttons. Requires a Nerd Font installed in your terminal.

Community Themes

Press # to open theme switcher, then Tab to browse 453 community color schemes. Supports search, live preview, color swatches. Press Enter to save.

Community themes are converted from iTerm2 color schemes. Stored by scheme name:

{
  "ui": {
    "theme": {
      "name": "default",
      "community": "Catppuccin Mocha",
      "overrides": { "primary": "#ff79c6" }
    }
  }
}

To regenerate community themes from upstream:

git clone https://github.com/mbadolato/iTerm2-Color-Schemes ~/code/iTerm2-Color-Schemes
./scripts/generate-schemes.sh [path-to-repo]

Per-Project Themes

Each project can have its own theme. When switching with @, theme changes automatically.

{
  "projects": {
    "list": [
      { "name": "api", "path": "~/code/api", "theme": { "name": "dracula" } },
      { "name": "web", "path": "~/code/web", "theme": { "name": "default", "community": "Catppuccin Mocha" } },
      { "name": "tools", "path": "~/code/tools" }
    ]
  }
}

Set per-project: press #, then ctrl+s to toggle scope to "Set for this project".

Resolution order: project theme > global ui.theme > "default".

Programmatic Theme Registration

import "github.com/marcus/sidecar/internal/styles"

myTheme := styles.Theme{
    Name:        "my-theme",
    DisplayName: "My Custom Theme",
    Colors: styles.ColorPalette{
        Primary:   "#FF5500",
        Secondary: "#00FF55",
        // ... all other colors
    },
}

styles.RegisterTheme(myTheme)
styles.ApplyTheme("my-theme")

API Reference

styles.ListThemes()                    // []string of available theme names
styles.GetTheme("dracula")             // Theme struct
styles.IsValidTheme("my-theme")        // bool
styles.IsValidHexColor("#FF5500")       // bool
styles.GetCurrentTheme()               // Theme
styles.GetCurrentThemeName()           // string
styles.ApplyTheme("dracula")
styles.ApplyThemeWithOverrides("default", map[string]string{"primary": "#FF5500"})

// Resolve effective theme for a project path (project > global > default)
import "github.com/marcus/sidecar/internal/theme"
resolved := theme.ResolveTheme(cfg, "/path/to/project")
theme.ApplyResolved(resolved)

Design Tips

1. Contrast: Ensure text colors have sufficient contrast against backgrounds
2. Consistency: Use related colors from the same palette (Tailwind, Material, etc.)
3. Diff visibility: Diff backgrounds should be subtle but visible
4. Toast readability: Toast text colors should contrast with success/error backgrounds

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