MainMenu.kv

<MainMenu>:
    FitImage:
        source: 'MenuImage.jpg'
    MDBoxLayout:
        orientation: 'vertical'
        padding: 30
        spacing: 10

        MDLabel:
            size_hint: 1, 0.2
            valign: 'top'
            halign: 'center'
            text: 'Ф р а к т а л ы'
            theme_text_color: "Custom"
            text_color: 1, 1, 1, 1
            font_style: 'H3'
            italic: True

        Widget:
            size_hint: 1, 0.25

        MDRaisedButton:
            pos_hint:{"center_x": 0.5, "center_y": 0.5}
            size_hint: 0.35, 0.1
            text: "Начать"
            text_color: 1, 1, 1, 1
            md_bg_color: .43, .43, .43, 0.7
            on_release:
                root.manager.transition.direction = 'up'
                root.manager.current = 'fractals'

        MDRaisedButton:
            pos_hint:{"center_x": 0.5, "center_y": 0.5}
            size_hint: 0.35, 0.1
            text: "Выход"
            text_color: 1, 1, 1, 1
            md_bg_color: .43, .43, .43, 0.7
            on_release: exit()
        Widget:
            size_hint: 1, 0.25