title: How do you set Axis FontSize in Altair?
body: <p>I would like to increase the X-Axis (or Y-Axis for that matter) fontSize to 16 (or any value) in the following Altair graph. I could not find any example in the Altair documentation here: <a href="https://altair-viz.github.io/index.html" rel="noreferrer">https://altair-viz.github.io/index.html</a>. I am using Jupyter Lab for visualization. Intuitively alt.Axis should take FontSize argument</p>
  <pre><code>import altair as alt
  from vega_datasets import data
  cars = data.cars()
  
  alt.Chart(cars).mark_point().encode(
      alt.X('Horsepower', axis=alt.Axis(title=&quot;HORSEPOWER&quot;)),
      alt.Y('Miles_per_Gallon', axis=alt.Axis(title=&quot;Miles Per Gallon&quot;)),
      color='Origin',
      shape='Origin'
  )
  </code></pre>
  <p><img src="https://i.stack.imgur.com/1ht6l.png" alt="" /></p>