diff --git a/color.go b/color.go
index b0a1b34..9ee7eea 100644
--- a/color.go
+++ b/color.go
@@ -48,8 +48,6 @@ type Window struct {
 }
 
 func (w *Window) color_init() {
-	theme := "Gruvbox"
-	transparent := true
 	if transparent {
 		w.src.background_color = Transparent
 		w.dst.background_color = Transparent
diff --git a/main.go b/main.go
index 3835941..2278a8e 100644
--- a/main.go
+++ b/main.go
@@ -17,6 +17,9 @@ var (
 	lang_page      = tview.NewFlex()
 	pages          = tview.NewPages()
 	window         Window
+	// config
+	theme       string = "Gruvbox"
+	transparent bool   = true
 )
 
 func main() {
diff --git a/ui.go b/ui.go
index 95063e5..94fd421 100644
--- a/ui.go
+++ b/ui.go
@@ -4,69 +4,99 @@ import (
 	"github.com/gdamore/tcell/v2"
 )
 
-func ui_init() {
-	// page
-	translate_page.SetInputCapture(TranslatePageHandler)
-
+func update_background() {
 	// box
-	src_box.SetBorder(true).
-		SetTitle(translator.src_lang).
-		SetBorderColor(window.src.border_color).
-		SetTitleColor(window.src.border_color).
-		SetBackgroundColor(window.src.background_color)
+	src_box.SetBackgroundColor(window.src.background_color)
 	src_box.SetTextStyle(tcell.StyleDefault.
 		Background(window.src.background_color).
 		Foreground(window.src.foreground_color))
-	src_box.SetSelectedStyle(tcell.StyleDefault.
-		Background(window.src.selected_color).
-		Foreground(window.src.foreground_color))
-	src_box.SetInputCapture(SrcBoxHandler)
 
-	dst_box.SetBorder(true).
-		SetTitle(translator.dst_lang).
-		SetBorderColor(window.dst.border_color).
-		SetTitleColor(window.dst.border_color).
-		SetBackgroundColor(window.dst.background_color)
-	dst_box.SetTextColor(window.dst.foreground_color)
+	dst_box.SetBackgroundColor(window.dst.background_color)
 
 	// dropdown
-	src_dropdown.SetOptions(Lang, nil).
-		SetCurrentOption(IndexOf(translator.src_lang, Lang))
+	src_dropdown.SetBackgroundColor(window.src.background_color)
 	src_dropdown.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))
-	src_dropdown.SetFieldBackgroundColor(window.src.selected_color).
-		SetFieldTextColor(window.src.foreground_color).
-		SetPrefixTextColor(window.dst.prefix_color)
-	src_dropdown.SetBorder(true).
-		SetTitle(translator.src_lang).
-		SetBackgroundColor(window.src.background_color).
-		SetBorderColor(window.src.border_color).
-		SetTitleColor(window.src.border_color)
-	src_dropdown.SetSelectedFunc(SrcSelected)
-	src_dropdown.SetDoneFunc(SrcDropDownHandler)
 
-	dst_dropdown.SetOptions(Lang, nil).
-		SetCurrentOption(IndexOf(translator.dst_lang, Lang))
+	dst_dropdown.SetBackgroundColor(window.dst.background_color)
+	// dst_dropdown.SetFieldBackgroundColor(window.src.selected_color)
 	dst_dropdown.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))
+}
+
+func ui_init() {
+	update_background()
+
+	// handler
+	pages.SetInputCapture(PagesHandler)
+	translate_page.SetInputCapture(TranslatePageHandler)
+	src_dropdown.SetDoneFunc(SrcDropDownHandler)
+	src_dropdown.SetSelectedFunc(SrcSelected)
+	dst_dropdown.SetDoneFunc(DstDropDownHandler)
+	dst_dropdown.SetSelectedFunc(DstSelected)
+
+	// box
+	src_box.SetBorder(true).
+		SetTitle(translator.src_lang).
+		SetBorderColor(window.src.border_color).
+		SetTitleColor(window.src.border_color)
+	src_box.SetSelectedStyle(tcell.StyleDefault.
+		Background(window.src.selected_color).
+		Foreground(window.src.foreground_color))
+
+	dst_box.SetBorder(true).
+		SetTitle(translator.dst_lang).
+		SetBorderColor(window.dst.border_color).
+		SetTitleColor(window.dst.border_color)
+	dst_box.SetTextColor(window.dst.foreground_color)
+
+	// dropdown
+	src_dropdown.SetOptions(Lang, nil).
+		SetCurrentOption(IndexOf(translator.src_lang, Lang))
+	src_dropdown.SetFieldBackgroundColor(window.src.selected_color).
+		SetFieldTextColor(window.src.foreground_color).
+		SetPrefixTextColor(window.dst.prefix_color)
+	src_dropdown.SetBorder(true).
+		SetTitle(translator.src_lang).
+		SetBorderColor(window.src.border_color).
+		SetTitleColor(window.src.border_color)
+
+	dst_dropdown.SetOptions(Lang, nil).
+		SetCurrentOption(IndexOf(translator.dst_lang, Lang))
 	dst_dropdown.SetFieldBackgroundColor(window.src.selected_color).
 		SetFieldTextColor(window.src.foreground_color).
 		SetPrefixTextColor(window.dst.prefix_color)
 	dst_dropdown.SetBorder(true).
 		SetTitle(translator.dst_lang).
-		SetBackgroundColor(window.dst.background_color).
 		SetBorderColor(window.dst.border_color).
 		SetTitleColor(window.dst.border_color)
-	dst_dropdown.SetSelectedFunc(DstSelected)
-	dst_dropdown.SetDoneFunc(DstDropDownHandler)
+}
+
+func PagesHandler(event *tcell.EventKey) *tcell.EventKey {
+	key := event.Key()
+
+	switch key {
+	case tcell.KeyCtrlT:
+		if transparent {
+			window.src.background_color = Themes[theme]["bg"]
+			window.dst.background_color = Themes[theme]["bg"]
+		} else {
+			window.src.background_color = Transparent
+			window.dst.background_color = Transparent
+		}
+		update_background()
+		transparent = !transparent
+	}
+
+	return event
 }
 
 func TranslatePageHandler(event *tcell.EventKey) *tcell.EventKey {
@@ -75,6 +105,21 @@ func TranslatePageHandler(event *tcell.EventKey) *tcell.EventKey {
 	switch key {
 	case tcell.KeyEsc:
 		pages.ShowPage("lang_page")
+	case tcell.KeyCtrlJ:
+		result, err := translator.Translate(src_box.GetText())
+		if err != nil {
+			dst_box.SetText(err.Error())
+		} else {
+			dst_box.SetText(result)
+		}
+	case tcell.KeyCtrlQ:
+		src_box.SetText("", true)
+	case tcell.KeyCtrlN:
+		translator.PlaySound(translator.src_lang, src_box.GetText())
+	case tcell.KeyCtrlP:
+		translator.PlaySound(translator.dst_lang, dst_box.GetText(false))
+	case tcell.KeyCtrlS:
+		dst_box.SetText("SSS")
 	}
 
 	return event
@@ -109,30 +154,3 @@ func DstDropDownHandler(key tcell.Key) {
 		pages.HidePage("lang_page")
 	}
 }
-
-func SrcBoxHandler(event *tcell.EventKey) *tcell.EventKey {
-	key := event.Key()
-	// panic(event.Name())
-
-	switch key {
-	case tcell.KeyCtrlJ:
-		result, err := translator.Translate(src_box.GetText())
-		if err != nil {
-			dst_box.SetText(err.Error())
-		} else {
-			dst_box.SetText(result)
-		}
-	case tcell.KeyCtrlQ:
-		src_box.SetText("", true)
-	case tcell.KeyCtrlN:
-		translator.PlaySound(translator.src_lang, src_box.GetText())
-	case tcell.KeyCtrlP:
-		translator.PlaySound(translator.dst_lang, dst_box.GetText(false))
-	case tcell.KeyCtrlT:
-		dst_box.SetText("TTT")
-	case tcell.KeyCtrlS:
-		dst_box.SetText("SSS")
-	}
-
-	return event
-}