Fix pane border overflow

internal/tui/update.go

@@ -42,9 +42,27 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	case tea.WindowSizeMsg:
 		m.width = msg.Width
 		m.height = msg.Height - 1
-		m.list.SetSize(msg.Width/2, m.height)
-		m.detail.Width = msg.Width - msg.Width/2
-		m.detail.Height = m.height
+
+		leftWidth := msg.Width / 2
+		rightWidth := msg.Width - leftWidth
+		leftHeight := m.height
+		rightHeight := m.height
+
+		if m.focus == listPane {
+			leftWidth -= 2
+			leftHeight -= 2
+		} else {
+			rightWidth -= 2
+			rightHeight -= 2
+		}
+
+		leftWidth -= 2
+		rightWidth -= 2
+
+		m.list.SetSize(leftWidth, leftHeight)
+		m.detail.Width = rightWidth
+		m.detail.Height = rightHeight
+
 		if m.focus == listPane {
 			m.list, cmd = m.list.Update(msg)
 		}

internal/tui/view.go

@@ -18,15 +18,35 @@ func (m Model) View() string {
 	listView := m.list.View()
 	detailView := m.detail.View()
 
-	left := listStyle.Width(m.width / 2).Height(m.height).Render(listView)
-	right := detailStyle.Width(m.width - m.width/2).Height(m.height).Render(detailView)
+	// compute dimensions for each pane accounting for padding and focus border
+	leftWidth := m.width / 2
+	rightWidth := m.width - leftWidth
+	leftHeight := m.height
+	rightHeight := m.height
+
+	if m.focus == listPane {
+		leftWidth -= 2 // border
+		leftHeight -= 2
+	} else {
+		rightWidth -= 2
+		rightHeight -= 2
+	}
+
+	// account for horizontal padding
+	leftWidth -= 2
+	rightWidth -= 2
+
+	left := listStyle.Width(leftWidth).Height(leftHeight).Render(listView)
+	right := detailStyle.Width(rightWidth).Height(rightHeight).Render(detailView)
+
 	if m.focus == listPane {
 		left = focusedStyle.Render(left)
 	} else {
 		right = focusedStyle.Render(right)
 	}
-	panes := lipgloss.JoinHorizontal(lipgloss.Top, left, right)
 
+	// join panes and status bar
+	panes := lipgloss.JoinHorizontal(lipgloss.Top, left, right)
 	status := fmt.Sprintf("VIEW MODE • %d entries", len(m.hosts.Entries))
 	bar := statusStyle.Width(m.width).Render(status)
 	return lipgloss.JoinVertical(lipgloss.Left, panes, bar)