Interoperability boosts in March browser releases
The March stable releases of Chrome 99 and 100, Firefox 98, and Safari 15.4 brought a meaningful set of web platform features to all three major browser engines. Several CSS and HTML additions that had been missing from one or more engines are now available everywhere, which simplifies cross-browser development.
CSS Cascade Layers arrive everywhere
Chrome 99 and Safari 15.4 shipped support for @layer, completing coverage across Chrome, Firefox, and Safari. The @layer at-rule lets you organize styles into cascade layers, giving you explicit control over how specificity and source order interact across your stylesheets.
New blending and containment options
Chrome 100 added plus-lighter as a new value for the CSS mix-blend-mode property. This value is designed for cross-fading two DOM elements where the pixels in common regions have matching values, a scenario that previously produced visual artifacts because of how blending modes are computed.
Safari 15.4 filled two long-standing gaps. The contain property now works in Safari, enabling CSS containment for performance optimizations. Safari also added accent-color, which lets you set the accent color for form controls such as checkboxes and radio buttons, and landed support for the :focus-visible pseudo-class, completing that feature across all engines.
The <dialog> element is now fully supported
Firefox 98 and Safari 15.4 both shipped the <dialog> element, meaning the native dialog box primitive is finally available across all major browsers. This gives developers a built-in, accessible way to create modal and non-modal dialogs without relying on JavaScript libraries.
Previews in beta releases
March also brought beta versions of Chrome 101 and Firefox 99, giving developers a heads-up on features that will reach stable channels soon.
HWB color in Chrome 101
The Chrome 101 beta includes support for hwb() color notation. This function specifies colors by hue, whiteness, and blackness components, with an optional alpha value for opacity, offering another way to express colors alongside rgb() and hsl().
PDF viewer detection in Firefox 99
Firefox 99 beta adds the pdfViewerEnabled property on the Navigator interface. You can use this boolean property to check whether the browser can display PDF files inline, which is useful for deciding whether to link to a PDF or offer an alternative viewer.
