Developer Docs - Apple TV Docs - TV Text Style
TVML offer's several different ways to style text. One thing that should be noted is that Apple TV apps are not HTML. The styling of apps should be more consistent with the Apple Design Language vs creating highly custom branded apps.
Below are some of the design patterns for text that will help you know what's available.
Text Styles
body
callout
caption1
caption2
footnote
headline
subhead
subtitle1
subtitle2
subtitle3
title1
title2
title3
Font Weight
ultralight
thin
light
regular
medium
semibold
bold
heavy
black
Text Tags (Bold/Italic/Strike)
This is Bold text
This is Italic text
This is Strike text
Font Family
Apple SD Gothic Neo
Arial
Copperplate
Courier
Helvetica
Helvetica Neue
Menlo
Times New Roman
Times New Roman Bold
Trebuchet MS
Text Shadow
https://developer.apple.com/documentation/tvml/text-shadow
Text shadows are great for titles overlaid on images and can be defined with the following syntax:
Summer Camp
Shadows may get clipped vertically depending on the wrapper size, so it's recommended to keep the shadow close to the text.