Custom Altair theme to enlarge font size and make it comfortably readable

altair_theme_readable.py

import altair as alt

# Custom theme for readability
def readable():   
    return {
        "config" : {
             "title": {'fontSize': 16},
             "axis": {
                  "labelFontSize": 14,
                  "titleFontSize": 14,
             },
             "header": {
                  "labelFontSize": 14,
                  "titleFontSize": 14,
             },
             "legend": {
                  "labelFontSize": 14,
                  "titleFontSize": 14,
             },
             "mark": {
                 'fontSize': 14,
                 "tooltip": {"content": "encoding"},  # enable tooltips
            },
        }
    }

alt.themes.register('readable', readable)
alt.themes.enable('readable')