# Special elements > Each element, its attributes, and the HTML that bongo writes in its place. bongo replaces `` elements in the HTML of each page, after the layouts render. They work in layouts, partials, and content. Write one as `` or as ``. For an introduction, see the [Templates guide](/templates/#special-elements). - Each `src` is a path relative to `assets/`. `` also takes paths in `content/`. - A `src` that does not exist fails the build. The error shows the element, and the content file and layouts that rendered it. - The built files get content-hashed names, such as `/app.3f9a1c2e.css`. On a site under `/blog/`, the URLs start with `/blog/`. - bongo does not replace them in [output files](/output-files/) or in the templates of [dynamic images](/dynamic-images/). ## Attribute values bongo reads attribute values as data, and never runs them as code: - A quoted value, `"…"` or `'…'`, is a string. - A bare value is a number, `true`, `false`, `null`, or else text, so `src=img/a.png` is a string. - A name with no value is `true`. ## `` Builds a stylesheet with LightningCSS. See [CSS](/css/). ```hbs ``` becomes: ```html ``` - `src` — the stylesheet. Required. - `inline` — write the built CSS in a `