I have no idea how it&#x27;s actually implemented, but it&#x27;s quite likely TVML is powered by HTML (and WebKit).<p>Rather than expecting developers to use an open-spec-compliant generic toolkit, they&#x27;ve just built modules on top of it to both make development easier and more importantly maintain a consistent UX.<p>You could just have pre-defined CSS classes and do much of the same thing, but it will not be as elegant nor as controlled. Taking over the HTML and JS interpreters just allows them greater control while respecting the role each component plays (markup, interactivity, styling, etc).