test-kivy-app/kivy_venv/lib/python3.11/site-packages/kivymd/uix/navigationrail/navigationrail.kv

<MDNavigationRailMenuButton>
    pos_hint: {"center_x": .5}
    theme_icon_color: "Custom"
    icon_color: self.theme_cls.onSurfaceVariantColor


<MDNavigationRailFabButton>
    type: "standard"
    pos_hint: {"center_x": .5}
    theme_bg_color: "Custom"
    md_bg_color: self.theme_cls.primaryColor
    theme_icon_color: "Custom"
    icon_color: self.theme_cls.onPrimaryColor


<MDNavigationRailItem>
    orientation: "vertical"
    size_hint: None, None
    width: "80dp"
    height: self.minimum_height
    spacing:
        ( \
        { \
        "selected": "8dp", \
        "labeled": "16dp", \
        "unselected": "16dp", \
        }[self._navigation_rail.type] \
        ) \
        if self._navigation_rail else 0


<MDNavigationRailItemIcon>
    canvas.before:
        Color:
            rgba:
                ( \
                ( \
                self.theme_cls.secondaryContainerColor \
                if not self.active_indicator_color else \
                self.active_indicator_color \
                )[:-1] + [self._alpha] \
                ) \
                if self._layer_color == self.theme_cls.transparentColor else \
                self._layer_color
        RoundedRectangle:
            group: "navigation-rail-rounded-rectangle"
            radius:
                ( \
                [ \
                ( \
                dp(16) \
                if self._navigation_rail.type != "unselected" else \
                dp(28) \
                ), \
                ] \
                ) \
                if self._navigation_rail else [0, ]
            pos:
                self.center_x - self._selected_region_width / 2, \
                ( \
                self.y \
                - ( \
                dp(4) \
                if self._navigation_rail.type != "unselected" else \
                dp(16) \
                ) \
                ) \
                if self._navigation_rail else 0
            size:
                self._selected_region_width, \
                ( \
                self.height \
                + ( \
                dp(8) \
                if self._navigation_rail.type != "unselected" else \
                self.width + dp(8)\
                ) \
                ) \
                if self._navigation_rail else 0

    pos_hint: {"center_x": .5}


<MDNavigationRailItemLabel>
    size_hint_y: None
    height: 0
    halign: "center"
    text_color: self.theme_cls.onSurfaceVariantColor
    font_style: "Label"
    role: "medium"


<MDNavigationRail>
    size_hint: None, 1
    width: "80dp"
    md_bg_color: self.theme_cls.surfaceColor

    BoxLayout:
        id: box_items
        orientation: "vertical"
        size_hint: None, None
        size: self.minimum_size
        pos_hint: {"center_x": .5}
        spacing:
            { \
            "selected": "12dp", \
            "labeled": "24dp", \
            "unselected": "36dp", \
            }[root.type]