diff --git a/internal/tui/tui.go b/internal/tui/tui.go
new file mode 100644
index 0000000..c56773b
--- /dev/null
+++ b/internal/tui/tui.go
@@ -0,0 +1,245 @@
+package tui
+
+import (
+	"fmt"
+	"strings"
+
+	"gemreader/internal/config"
+
+	"github.com/charmbracelet/bubbles/viewport"
+	markdown "github.com/MichaelMure/go-term-markdown"
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+)
+
+type pane int
+
+const (
+	tocPane pane = iota
+	contentPane
+)
+
+type model struct {
+	content         string
+	rawLines        []string
+	toc             []tocEntry
+	selectedTocIndex int
+	
+	tocViewport     viewport.Model
+	contentViewport viewport.Model
+
+	activePane   pane
+	helpVisible  bool
+	config       config.Config
+	windowWidth  int
+	windowHeight int
+}
+
+type tocEntry struct {
+	level int
+	text  string
+	line  int
+}
+
+func NewModel(content string, cfg config.Config) model {
+	rawLines := strings.Split(content, "\n")
+	toc := generateTOC(rawLines)
+
+	// Create viewports for the TOC and content
+	tocVP := viewport.New(0, 0)
+	contentVP := viewport.New(0, 0)
+
+	m := model{
+		content:         content,
+		rawLines:        rawLines,
+		toc:             toc,
+		tocViewport:     tocVP,
+		contentViewport: contentVP,
+		activePane:      contentPane,
+		helpVisible:     true,
+		config:          cfg,
+	}
+
+	return m
+}
+
+func generateTOC(lines []string) []tocEntry {
+	var toc []tocEntry
+	for i, line := range lines {
+		trimmed := strings.TrimSpace(line)
+		if strings.HasPrefix(trimmed, "#") {
+			level := 0
+			for _, char := range trimmed {
+				if char == '#' {
+					level++
+				} else {
+					break
+				}
+			}
+			headerText := strings.TrimSpace(trimmed[level:])
+			if headerText != "" {
+				toc = append(toc, tocEntry{
+					level: level,
+					text:  headerText,
+					line:  i,
+				})
+			}
+		}
+	}
+	return toc
+}
+
+func (m model) Init() tea.Cmd {
+	return nil
+}
+
+func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	var (
+		cmd  tea.Cmd
+		cmds []tea.Cmd
+	)
+
+	switch msg := msg.(type) {
+	case tea.WindowSizeMsg:
+		m.windowWidth = msg.Width
+		m.windowHeight = msg.Height
+
+		// Calculate pane widths
+		tocWidth := int(float64(m.windowWidth) * 0.3)
+		contentWidth := m.windowWidth - tocWidth
+
+		// Set viewport dimensions
+		m.tocViewport.Width = tocWidth - 2 // Adjust for border
+		m.tocViewport.Height = m.windowHeight - 2
+		m.contentViewport.Width = contentWidth - 2
+		m.contentViewport.Height = m.windowHeight - 2
+
+		// Set content for viewports
+		m.tocViewport.SetContent(m.renderTOC())
+		renderedContent := string(markdown.Render(m.content, contentWidth-4, 6))
+		m.contentViewport.SetContent(renderedContent)
+
+
+	case tea.KeyMsg:
+		switch msg.String() {
+		case "q", "ctrl+c":
+			return m, tea.Quit
+		case "h", "?":
+			m.helpVisible = !m.helpVisible
+		case "tab":
+			if m.activePane == tocPane {
+				m.activePane = contentPane
+			} else {
+				m.activePane = tocPane
+			}
+		case "enter":
+			if m.activePane == tocPane && len(m.toc) > 0 {
+				// Jump to selected TOC entry
+				tocEntry := m.toc[m.selectedTocIndex]
+				
+				// Find the line in the rendered content
+				renderedLines := strings.Split(m.contentViewport.View(), "\n")
+				for i, line := range renderedLines {
+					if strings.Contains(strings.ToLower(line), strings.ToLower(tocEntry.text)) {
+						m.contentViewport.SetYOffset(i)
+						break
+					}
+				}
+				m.activePane = contentPane // Switch to content view after jumping
+			}
+		case "up", "k":
+			if m.activePane == tocPane {
+				if m.selectedTocIndex > 0 {
+					m.selectedTocIndex--
+					m.tocViewport.SetContent(m.renderTOC())
+				}
+			} else {
+				m.contentViewport.LineUp(1)
+			}
+		case "down", "j":
+			if m.activePane == tocPane {
+				if m.selectedTocIndex < len(m.toc)-1 {
+					m.selectedTocIndex++
+					m.tocViewport.SetContent(m.renderTOC())
+				}
+			} else {
+				m.contentViewport.LineDown(1)
+			}
+		case "pgup", "ctrl+u":
+			if m.activePane == contentPane {
+				m.contentViewport.ViewUp()
+			}
+		case "pgdn", "ctrl+d":
+			if m.activePane == contentPane {
+				m.contentViewport.ViewDown()
+			}
+		case "g", "home":
+			if m.activePane == contentPane {
+				m.contentViewport.GotoTop()
+			}
+		case "G", "end":
+			if m.activePane == contentPane {
+				m.contentViewport.GotoBottom()
+			}
+		}
+	}
+
+	// Update viewports
+	m.tocViewport, cmd = m.tocViewport.Update(msg)
+	cmds = append(cmds, cmd)
+	m.contentViewport, cmd = m.contentViewport.Update(msg)
+	cmds = append(cmds, cmd)
+
+	return m, tea.Batch(cmds...)
+}
+
+func (m model) View() string {
+	// Styles
+	tocStyle := lipgloss.NewStyle().
+		Border(lipgloss.RoundedBorder()).
+		BorderForeground(lipgloss.Color("63")) // Default border color
+	contentStyle := lipgloss.NewStyle().
+		Border(lipgloss.RoundedBorder()).
+		BorderForeground(lipgloss.Color("63")) // Default border color
+
+	// Highlight active pane
+	if m.activePane == tocPane {
+		tocStyle = tocStyle.BorderForeground(lipgloss.Color("226")) // Yellow
+	} else {
+		contentStyle = contentStyle.BorderForeground(lipgloss.Color("226")) // Yellow
+	}
+
+	// Render panes
+	tocView := tocStyle.Render(m.tocViewport.View())
+	contentView := contentStyle.Render(m.contentViewport.View())
+
+	// Join panes horizontally
+	mainView := lipgloss.JoinHorizontal(lipgloss.Top, tocView, contentView)
+
+	// Help text
+	var helpText string
+	if m.helpVisible {
+		s := "Navigate: ↑/↓ j/k | PgUp/PgDn | g/G | Tab (switch panes) | h/? (help) | q (quit)"
+		helpText = lipgloss.NewStyle().Foreground(lipgloss.Color("240")).Render(s)
+	}
+
+	return mainView + helpText
+}
+
+func (m model) renderTOC() string {
+	if len(m.toc) == 0 {
+		return "No table of contents found."
+	}
+
+	var content strings.Builder
+	content.WriteString("Table of Contents:\n\n")
+	for i, entry := range m.toc {
+		indent := strings.Repeat("  ", entry.level-1)
+		if i == m.selectedTocIndex {
+			content.WriteString(fmt.Sprintf("%s> %s\n", indent, entry.text))
+		} else {
+			content.WriteString(fmt.Sprintf("%s  %s\n", indent, entry.text))
+		}
+	}
+	return content.String()
+}
\ No newline at end of file