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Published: September 22, 2026

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Chrome 154 is rolling out now, and this post shares some of the key features from
the release. Read the full [Chrome 154 release notes](https://developer.chrome.com/release-notes/154.md.txt).

Highlights from this release:

- [Responsively-sized `<iframe>`](https://developer.chrome.com/blog/new-in-chrome-154.md.txt#responsive-iframes) lets an `<iframe>` size itself based on the intrinsic size of its embedded document.
- [CSS `scroll-marker-group` modes](https://developer.chrome.com/blog/new-in-chrome-154.md.txt#scroll-marker-group-modes) adds `links` and `tabs` modes to configure the focus order and accessibility semantics of scroll markers.
- [CSS `text-decoration-inset`](https://developer.chrome.com/blog/new-in-chrome-154.md.txt#text-decoration-inset) lets you adjust the start and end points of text decorations.

## Responsively-sized `<iframe>`

Chrome 154 adds support for responsively-sized iframes, letting an `<iframe>`
element in a parent document size itself to the embedded document's layout
overflow sizing so that scrolling in the child document is avoided. This replaces
the pattern where you manually measure iframe content, send dimensions with
`postMessage()`, and update the iframe size in the embedding page.

To size an iframe to its content height, use the `frame-sizing` CSS property on
the `<iframe>` element in the embedding page:

```css
.embed {
  width: 100%;
  frame-sizing: content-height;
}
```

The embedded document must also opt in by including a
`<meta name="responsive-embedded-sizing">` element in its `<head>`:

```html
<meta name="responsive-embedded-sizing" content="allow-origins=*">
```

For more details and demos, see
[Responsive iframes in Chrome 154](https://developer.chrome.com/blog/responsive-iframes.md.txt).

## CSS `scroll-marker-group` modes

The [`scroll-marker-group`](https://developer.mozilla.org/docs/Web/CSS/Reference/Properties/scroll-marker-group)
property controls whether a scroll container generates
a `::scroll-marker-group` pseudo-element before or after its contents. Chrome 154
enhances `scroll-marker-group` with two modes that set the focus order and
WAI-ARIA accessibility semantics of `::scroll-marker-group` and
`::scroll-marker`:

```css
/* Links mode (default) */
scroll-marker-group: after links;

/* Tabs mode */
scroll-marker-group: before tabs;
```

## CSS `text-decoration-inset`

By default, an element's text decoration (such as an underline, overline, or
line-through) is the same length as the rendered text. The
`text-decoration-inset` CSS property lets you adjust the start and end points of
an element's text decoration so that it is inset from, extended beyond, or
shifted relative to the text run edges.

`text-decoration-inset` accepts `auto`, length, and percentage values using
either one-value or two-value syntax, for example to inset both ends by 10px:

```css
text-decoration-inset: 10px;
```

Positive values inset the decoration (making it shorter), while negative values
outset the decoration (making it longer). This lets you fine-tune decoration
spacing and create animated underline reveal effects with CSS text decorations
instead of background gradients or extra elements.

For more information, see the
[`text-decoration-inset` documentation on MDN](https://developer.mozilla.org/docs/Web/CSS/Reference/Properties/text-decoration-inset).

## Further reading

This covers only some key highlights. Check the following links for additional
changes in Chrome 154:

- [Release notes for Chrome 154](https://developer.chrome.com/release-notes/154.md.txt).
- [ChromeStatus.com updates for Chrome
  154](https://chromestatus.com/features#milestone%3D154).
- [Chrome release calendar](https://chromiumdash.appspot.com/schedule).

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