# SEM-001: unknown element

**Error**: the page doesn't build until this is fixed.

Hypra knows every HTML element, so a name it doesn't know is usually a typo, which a browser would show as
an empty, unstyled box. The message suggests the closest name.

## Fails

```hypra fails
page(title: "Shoes", description: "All our running shoes, from light racers to trail shoes.") {
  h1 "Shoes"
  buton "Buy"
}
```

## Fixed

```hypra passes
page(title: "Shoes", description: "All our running shoes, from light racers to trail shoes.") {
  h1 "Shoes"
  button "Buy"
  model-viewer(src: "/models/runner-x.glb", alt: "Runner X in 3D")
}
```

Custom elements and web components have a dash in their name, like `model-viewer`, and pass as they are. Components start with a capital letter.