from typing import Dict
from typing import Any


def my_theme() -> Dict[str, Any]:
    """Define an Altair theme to use in all visualisations.

    This defines a simple theme, specifying the aspect ratio of 4:6 
    and removing the grid from the figure which is distracting.

    """
    font = "Roboto"
    return {
        "config": {
            "view": {"height": 400, "width": 600},
            "legend": {
                "titleFontSize": 20,
                "labelFontSize": 16,
                "labelFont": font,
                "titleFont": font,
            },
            "axis": {
                "grid": False,
                "labelFontSize": 16,
                "titleFontSize": 20,
                "labelFont": font,
                "titleFont": font,
            },
            "header": {
                "titleFontSize": 22,
                "labelFontSize": 18,
                "titleFont": font,
                "labelFont": font,
            },
            "background": "white",
        }
    }