my.kv

<MainWindow>:
    no_of_questions:no_of_questions
    fib:fib
    name:"main"
    GridLayout:
        cols:1
        GridLayout:
            cols:2
            Label:
                text:"QUESTIONS"
                font_size:50
                background_color:(1,181/255,213/255,0.9)
                canvas.before:
                    Color:
                        rgba:self.background_color
                    Rectangle:
                        size:self.size
                        pos:self.pos
                color:(1,0,0,0.7)
                bold:True
                italic:True
                outline_color:(0,0,0)
                outline_width: 2
            TextInput:
                id: no_of_questions
                font_size:100
                halign:'center'
                multiline : False
            Label:
                text:"FILL IN THE BLANKS"
                font_size:40
                background_color:(1,99/255,71/255,1)
                canvas.before:
                    Color:
                        rgba:self.background_color
                    Rectangle:
                        size:self.size
                        pos:self.pos
                color:(1,0,0,0.7)
                bold:True
                italic:True
                outline_color:(0,0,0)
                outline_width: 2
            TextInput:
                id: fib
                font_size:100
                halign:'center'
                multiline : False

        Button:
            text:"SUBMIT"
            font_size:40
            color:(60/255,211/255,0,0.7)
            bold:True
            italic:True
            outline_color:(0,0,0)
            outline_width: 2
            size_hint_y: None
            height:'200dp'
            background_normal:''
            background_color: (0.19,0.8,0.55,0.7)
            on_release:
                root.button()
                app.root.current="second"
                root.manager.transition.direction="left"
            

<SecondWindow>:
    name:"second"
    Button:
        text:"File has been downloaded to output.txt"
        background_normal:''

        background_color: (0.19,0.8,0.55,0.7)
        font_size:40
        color:(60/255,211/255,0,0.7)
        bold:True
        italic:True
        outline_color:(0,0,0)
        outline_width: 4