diff --git a/main.go b/main.go
index bd9a704..e2628d0 100644
--- a/main.go
+++ b/main.go
@@ -9,15 +9,15 @@ var (
 	// Translate
 	translator = NewTranslator()
 	// UI
-	app            = tview.NewApplication()
-	src_box        = tview.NewTextArea()
-	dst_box        = tview.NewTextView()
-	src_dropdown   = tview.NewDropDown()
-	dst_dropdown   = tview.NewDropDown()
-	translate_page = tview.NewFlex()
-	lang_page      = tview.NewFlex()
-	pages          = tview.NewPages()
-	window         Window
+	app             = tview.NewApplication()
+	srcBox         = tview.NewTextArea()
+	dstBox         = tview.NewTextView()
+	srcDropDown    = tview.NewDropDown()
+	dstDropDown    = tview.NewDropDown()
+	translateWindow = tview.NewFlex()
+	langWindow      = tview.NewFlex()
+	mainPage        = tview.NewPages()
+	window          Window
 	// config
 	config      = viper.New()
 	theme       string
@@ -29,22 +29,22 @@ func main() {
 	configInit()
 	window.colorInit()
 	uiInit()
-	translate_page.SetDirection(tview.FlexColumn).
-		AddItem(src_box, 0, 1, true).
-		AddItem(dst_box, 0, 1, false)
-	lang_page.SetDirection(tview.FlexRow).
+	translateWindow.SetDirection(tview.FlexColumn).
+		AddItem(srcBox, 0, 1, true).
+		AddItem(dstBox, 0, 1, false)
+	langWindow.SetDirection(tview.FlexRow).
 		AddItem(nil, 0, 1, false).
 		AddItem(tview.NewFlex().SetDirection(tview.FlexColumn).
 			AddItem(nil, 0, 1, false).
-			AddItem(src_dropdown, 32, 1, true).
-			AddItem(dst_dropdown, 32, 1, false).
+			AddItem(srcDropDown, 32, 1, true).
+			AddItem(dstDropDown, 32, 1, false).
 			AddItem(nil, 0, 1, false), 20, 1, true).
 		AddItem(nil, 0, 1, false)
 
-	pages.AddPage("translate_page", translate_page, true, true)
-	pages.AddPage("lang_page", lang_page, true, false)
+	mainPage.AddPage("translatePage", translateWindow, true, true)
+	mainPage.AddPage("langPage", langWindow, true, false)
 
-	if err := app.SetRoot(pages, true).
+	if err := app.SetRoot(mainPage, true).
 		EnableMouse(true).Run(); err != nil {
 		panic(err)
 	}
diff --git a/ui.go b/ui.go
index 4fa1c3e..d44999b 100644
--- a/ui.go
+++ b/ui.go
@@ -6,24 +6,24 @@ import (
 
 func updateBackground() {
 	// box
-	src_box.SetBackgroundColor(window.src.background_color)
-	src_box.SetTextStyle(tcell.StyleDefault.
+	srcBox.SetBackgroundColor(window.src.background_color)
+	srcBox.SetTextStyle(tcell.StyleDefault.
 		Background(window.src.background_color).
 		Foreground(window.src.foreground_color))
 
-	dst_box.SetBackgroundColor(window.dst.background_color)
+	dstBox.SetBackgroundColor(window.dst.background_color)
 
 	// dropdown
-	src_dropdown.SetBackgroundColor(window.src.background_color)
-	src_dropdown.SetListStyles(tcell.StyleDefault.
+	srcDropDown.SetBackgroundColor(window.src.background_color)
+	srcDropDown.SetListStyles(tcell.StyleDefault.
 		Background(window.src.background_color).
 		Foreground(window.src.foreground_color),
 		tcell.StyleDefault.
 			Background(window.src.selected_color).
 			Foreground(window.src.prefix_color))
 
-	dst_dropdown.SetBackgroundColor(window.dst.background_color)
-	dst_dropdown.SetListStyles(tcell.StyleDefault.
+	dstDropDown.SetBackgroundColor(window.dst.background_color)
+	dstDropDown.SetListStyles(tcell.StyleDefault.
 		Background(window.src.background_color).
 		Foreground(window.src.foreground_color),
 		tcell.StyleDefault.
@@ -33,42 +33,42 @@ func updateBackground() {
 
 // update title and option
 func updateTitle() {
-	src_box.SetTitle(translator.srcLang)
-	dst_box.SetTitle(translator.dstLang)
-	src_dropdown.SetCurrentOption(IndexOf(translator.srcLang, Lang))
-	src_dropdown.SetTitle(translator.srcLang)
-	dst_dropdown.SetCurrentOption(IndexOf(translator.dstLang, Lang))
-	dst_dropdown.SetTitle(translator.dstLang)
+	srcBox.SetTitle(translator.srcLang)
+	dstBox.SetTitle(translator.dstLang)
+	srcDropDown.SetCurrentOption(IndexOf(translator.srcLang, Lang))
+	srcDropDown.SetTitle(translator.srcLang)
+	dstDropDown.SetCurrentOption(IndexOf(translator.dstLang, Lang))
+	dstDropDown.SetTitle(translator.dstLang)
 }
 
 func uiInit() {
 	// box
-	src_box.SetBorder(true).
+	srcBox.SetBorder(true).
 		SetBorderColor(window.src.border_color).
 		SetTitleColor(window.src.border_color)
-	src_box.SetSelectedStyle(tcell.StyleDefault.
+	srcBox.SetSelectedStyle(tcell.StyleDefault.
 		Background(window.src.selected_color).
 		Foreground(window.src.foreground_color))
 
-	dst_box.SetBorder(true).
+	dstBox.SetBorder(true).
 		SetBorderColor(window.dst.border_color).
 		SetTitleColor(window.dst.border_color)
-	dst_box.SetTextColor(window.dst.foreground_color)
+	dstBox.SetTextColor(window.dst.foreground_color)
 
 	// dropdown
-	src_dropdown.SetOptions(Lang, nil)
-	src_dropdown.SetFieldBackgroundColor(window.src.selected_color).
+	srcDropDown.SetOptions(Lang, nil)
+	srcDropDown.SetFieldBackgroundColor(window.src.selected_color).
 		SetFieldTextColor(window.src.foreground_color).
 		SetPrefixTextColor(window.dst.prefix_color)
-	src_dropdown.SetBorder(true).
+	srcDropDown.SetBorder(true).
 		SetBorderColor(window.src.border_color).
 		SetTitleColor(window.src.border_color)
 
-	dst_dropdown.SetOptions(Lang, nil)
-	dst_dropdown.SetFieldBackgroundColor(window.src.selected_color).
+	dstDropDown.SetOptions(Lang, nil)
+	dstDropDown.SetFieldBackgroundColor(window.src.selected_color).
 		SetFieldTextColor(window.src.foreground_color).
 		SetPrefixTextColor(window.dst.prefix_color)
-	dst_dropdown.SetBorder(true).
+	dstDropDown.SetBorder(true).
 		SetBorderColor(window.dst.border_color).
 		SetTitleColor(window.dst.border_color)
 
@@ -76,11 +76,11 @@ func uiInit() {
 	updateTitle()
 
 	// handler
-	pages.SetInputCapture(pagesHandler)
-	translate_page.SetInputCapture(translatePageHandler)
-	src_dropdown.SetDoneFunc(srcDropDownHandler).
+	mainPage.SetInputCapture(pagesHandler)
+	translateWindow.SetInputCapture(translatePageHandler)
+	srcDropDown.SetDoneFunc(srcDropDownHandler).
 		SetSelectedFunc(srcSelected)
-	dst_dropdown.SetDoneFunc(dstDropDownHandler).
+	dstDropDown.SetDoneFunc(dstDropDownHandler).
 		SetSelectedFunc(dstSelected)
 }
 
@@ -108,41 +108,41 @@ func translatePageHandler(event *tcell.EventKey) *tcell.EventKey {
 
 	switch key {
 	case tcell.KeyEsc:
-		pages.ShowPage("lang_page")
+		mainPage.ShowPage("langPage")
 	case tcell.KeyCtrlJ:
-		message := src_box.GetText()
+		message := srcBox.GetText()
 		if len(message) > 0 {
 			result, err := translator.Translate(message)
 			if err != nil {
-				dst_box.SetText(err.Error())
+				dstBox.SetText(err.Error())
 			} else {
-				dst_box.SetText(result)
+				dstBox.SetText(result)
 			}
 		}
 	case tcell.KeyCtrlQ:
-		src_box.SetText("", true)
+		srcBox.SetText("", true)
 	case tcell.KeyCtrlS:
 		translator.srcLang, translator.dstLang = translator.dstLang, translator.srcLang
 		updateTitle()
-		src_text := src_box.GetText()
-		dst_text := dst_box.GetText(false)
+		src_text := srcBox.GetText()
+		dst_text := dstBox.GetText(false)
 		if len(dst_text) > 0 {
 			// GetText of Box contains "\n" if it has words
-			src_box.SetText(dst_text[:len(dst_text)-1], true)
+			srcBox.SetText(dst_text[:len(dst_text)-1], true)
 		} else {
-			src_box.SetText(dst_text, true)
+			srcBox.SetText(dst_text, true)
 		}
-		dst_box.SetText(src_text)
+		dstBox.SetText(src_text)
 	case tcell.KeyCtrlO:
 		// play source sound
 		if translator.soundLock.Available() {
-			message := src_box.GetText()
+			message := srcBox.GetText()
 			if len(message) > 0 {
 				translator.soundLock.Acquire()
 				go func() {
 					err := translator.PlaySound(translator.srcLang, message)
 					if err != nil {
-						src_box.SetText(err.Error(), true)
+						srcBox.SetText(err.Error(), true)
 					}
 				}()
 			}
@@ -151,13 +151,13 @@ func translatePageHandler(event *tcell.EventKey) *tcell.EventKey {
 	case tcell.KeyCtrlP:
 		// play destination sound
 		if translator.soundLock.Available() {
-			message := dst_box.GetText(false)
+			message := dstBox.GetText(false)
 			if len(message) > 0 {
 				translator.soundLock.Acquire()
 				go func() {
 					err := translator.PlaySound(translator.dstLang, message)
 					if err != nil {
-						dst_box.SetText(err.Error())
+						dstBox.SetText(err.Error())
 					}
 				}()
 			}
@@ -172,30 +172,30 @@ func translatePageHandler(event *tcell.EventKey) *tcell.EventKey {
 
 func srcSelected(text string, index int) {
 	translator.srcLang = text
-	src_box.SetTitle(text)
-	src_dropdown.SetTitle(text)
+	srcBox.SetTitle(text)
+	srcDropDown.SetTitle(text)
 }
 
 func dstSelected(text string, index int) {
 	translator.dstLang = text
-	dst_box.SetTitle(text)
-	dst_dropdown.SetTitle(text)
+	dstBox.SetTitle(text)
+	dstDropDown.SetTitle(text)
 }
 
 func srcDropDownHandler(key tcell.Key) {
 	switch key {
 	case tcell.KeyTAB:
-		app.SetFocus(dst_dropdown)
+		app.SetFocus(dstDropDown)
 	case tcell.KeyEsc:
-		pages.HidePage("lang_page")
+		mainPage.HidePage("langPage")
 	}
 }
 
 func dstDropDownHandler(key tcell.Key) {
 	switch key {
 	case tcell.KeyTAB:
-		app.SetFocus(src_dropdown)
+		app.SetFocus(srcDropDown)
 	case tcell.KeyEsc:
-		pages.HidePage("lang_page")
+		mainPage.HidePage("langPage")
 	}
 }