your-app/
├── main.go              # Entry point (minimal, ~21 lines)
├── types.go             # Type definitions, structs, enums
├── model.go             # Model initialization & layout calculation
├── update.go            # Message dispatcher
├── update_keyboard.go   # Keyboard handling
├── update_mouse.go      # Mouse handling
├── view.go              # View rendering & layouts
├── styles.go            # Lipgloss style definitions
├── config.go            # Configuration management
└── .claude/skills/bubbletea/  # This skill (bundled)

func (m model) calculateLayout() (int, int) {
    contentWidth := m.width
    contentHeight := m.height

    // Subtract UI elements
    if m.config.UI.ShowTitle {
        contentHeight -= 3  // title bar (3 lines)
    }
    if m.config.UI.ShowStatus {
        contentHeight -= 1  // status bar
    }

    // CRITICAL: Account for panel borders
    contentHeight -= 2  // top + bottom borders

    return contentWidth, contentHeight
}

// Calculate weights based on focus/accordion mode
leftWeight, rightWeight := 1, 1
if m.accordionMode && m.focusedPanel == "left" {
    leftWeight = 2  // Focused panel gets 2x weight
}

// Calculate actual widths from weights
totalWeight := leftWeight + rightWeight
leftWidth := (availableWidth * leftWeight) / totalWeight
rightWidth := availableWidth - leftWidth

// Calculate max text width to prevent wrapping
maxTextWidth := panelWidth - 4  // -2 borders, -2 padding

// Truncate ALL text before rendering
title = truncateString(title, maxTextWidth)
subtitle = truncateString(subtitle, maxTextWidth)

func truncateString(s string, maxLen int) string {
    if len(s) <= maxLen {
        return s
    }
    return s[:maxLen-1] + "…"
}

func (m model) handleLeftClick(msg tea.MouseMsg) (tea.Model, tea.Cmd) {
    if m.shouldUseVerticalStack() {
        // Vertical stack mode: use Y coordinates
        topHeight, _ := m.calculateVerticalStackLayout()
        relY := msg.Y - contentStartY

        if relY < topHeight {
            m.focusedPanel = "left"  // Top panel
        } else {
            m.focusedPanel = "right" // Bottom panel
        }
    } else {
        // Side-by-side mode: use X coordinates
        leftWidth, _ := m.calculateDualPaneLayout()

        if msg.X < leftWidth {
            m.focusedPanel = "left"
        } else {
            m.focusedPanel = "right"
        }
    }

    return m, nil
}

// BAD: Can cause misalignment
panelStyle := lipgloss.NewStyle().
    Border(border).
    Height(height)  // Don't do this!

// GOOD: Fill content lines to exact height
for len(lines) < innerHeight {
    lines = append(lines, "")
}
panelStyle := lipgloss.NewStyle().Border(border)

theme: "dark"
keybindings: "default"

layout:
  type: "dual_pane"
  split_ratio: 0.5
  accordion_mode: true

ui:
  show_title: true
  show_status: true
  mouse_enabled: true
  show_icons: true

github.com/charmbracelet/bubbletea
github.com/charmbracelet/lipgloss
github.com/charmbracelet/bubbles
gopkg.in/yaml.v3

github.com/charmbracelet/glamour       # Markdown rendering
github.com/charmbracelet/huh           # Forms
github.com/alecthomas/chroma/v2        # Syntax highlighting
github.com/evertras/bubble-table       # Interactive tables
github.com/koki-develop/go-fzf         # Fuzzy finder