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W3C CSS Working Group

Developing specifications for the CSS language

by Miriam Suzanne since

Miriam is an Invited Expert on the W3C CSS Working Group, helping to develop the next level of Cascading & Inheritance, in addition to other CSS standards.

Cascading Style Sheets (CSS) are the design language of the web – allowing authors and users to attach style (fonts, spacing, filter effects, style animations, and more) to structured documents and Web applications. By separating the presentation style from the content, CSS simplifies Web authoring and site maintenance.

Miriam is an editor on several specifications, and has lead the standardization of many popular CSS features since joining the group in 2020:

All my research, explainers, and proposals are available at css.oddbird.net.

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2025 CSSWG Posts

  1. Winging It post type

    Cross-Browser Anchor Positioning

    Anchor Positioning is available in all browsers. What’s next, with Eric Meyer.

    on Winging It episode 26 with James & Miriam on | 60 min

    It’s finally here! With the release of Firefox 145, CSS anchor positioning is available in all browsers. It’s still behind a flag in Firefox, so it isn’t Baseline Newly available quite yet. Join James Stuckey Weber, Miriam Suzanne, and Eric Meyer of Igalia as they talk about the emerging patterns...

    see all Winging It posts
  2. css:is(awesome) over a colorful nebula
    Talk post type

    Modern CSS Architecture

    A practical workshop on integrating modern CSS

    by Miriam Suzanne

    Past
    • – New York

      Smashing Workshop

    see all Talks & Workshops
  3. Winging It post type

    Mixins & Functions to Streamline CSS

    With special guest Roma Komarov

    on Winging It episode 24 with Miriam & Stacy on | 59 min

    The CSS Working Group got together in August to discuss a range of old and new issues. The following week, Miriam Suzanne and Stacy Kvernmo chatted with CSS expert Roma Komarov about how to create reusable and more flexible CSS using mixins and functions, what happened in the CSSWG meetings...

    see all Winging It posts
  4. W3C
    Talk post type

    CSS Functions & Mixins

    Is sass dead yet?

    by Miriam Suzanne

    Past
    • – Amsterdam, NL

      CSS Day

    see all Talks & Workshops
  5. fragment of an inverted triangle with the cascade -- cascade layers are highlighted below element-attached styles and above specificity
    Talk post type

    Cascading Layers of !mportance

    by Miriam Suzanne

    Past
    • – Cluj, Romania

      JS Heroes

    • – San Francisco, CA

      An Event Apart

    see all Talks & Workshops
  6. Grainy art-deco illustration of a rocket launch
    Podcast post type

    The Design of Web Design

    A web development podcast from LogRocket

    on PodRocket with Miriam Suzanne on

    I talk with Noel Minchow about the philosophy and evolution of web design. We explore CSS origins, the cascade, accessibility, and how the balance between user control and brand expression defines the spirit of the web.

    see all Podcast posts
  7. A cat sitting in a box thinking OMG. I have so many questions for this damn box.
    Talk post type

    Cascading Layouts

    A workshop on resilient CSS layouts

    by Miriam Suzanne

    Past
    • – Online

      OddBird Workshops

    see all Talks & Workshops
  8. Vivaldi podcast cover art with Bruce Lawson and Miriam
    Podcast post type

    Cascade Layers, Container Queries, Scope, and More

    on For a Better Web with Miriam Suzanne on

    I chat with Bruce Lawson about all things CSS. We geek out over the latest and greatest features like Cascade Layers, @Scope, Mixins, and Container Queries – exploring how these features impact web design.

    see all Podcast posts
  9. Two websites loaded on the WWW Hypermedia Browser, using the emulator hosted by Remy Sharp -- our workshop page, and the 11ty symposium site -- both rendered as plain text
    Talk post type

    Hints and Suggestions

    The design of web design

    by Miriam Suzanne

    Past
    • – online

      Smashing Meets

    • – Victoria, BC

      Camosun College

    see all Talks & Workshops
  10. A chain-link gate in black and white with a sign that says closed indefinitely, and a smaller warning with gruesome icons for entrapment (a person being smashed) and pinching (a hand going through gears)
    Article post type

    How do we move logical shorthands forward?

    There are several proposals, but one major road block

    by Miriam Suzanne on

    We’re trying to make progress on shorthand syntax for CSS logical properties. But the path forward depends on where we hope to be a decade from now.

    see all Article posts
  11. block-size, inline-size, size?
    Article post type

    Support Logical Shorthands in CSS

    Can we get this process unstuck?

    by Miriam Suzanne on

    The CSS Working Group recently resolved to add a size shorthand for setting both the width and height of an element. Many people asked about using it to set the ‘logical’ inline-size and block-size properties instead. But ‘logical shorthands’ have been stalled in the working group for years. Can we...

    see all Article posts
  12. Title card from the podcast with headshots of Kevin and Mia
    Podcast post type

    Getting more involved with CSS

    on General Musings with Kevin Powell with Miriam Suzanne on

    Kevin and I chat about getting involved with the development of the CSS language, from following along to opening issues, or even joining the CSS Working Group.

    see all Podcast posts

2024

  1. Mia from behind, standing at a laptop - speaking to a conference audience and gesturing to one side
    Talk post type

    Cascading Style Systems

    A workshop on resilient & maintainable CSS

    by Miriam Suzanne

    Past
    • – Sydney, Australia

      Web Directions Workshops

    • – Online

      Smashing Workshops

    see all Talks & Workshops
  2. Three mud turtles end-to-end on a small branch floating in the water
    Talk post type

    CSS Containers, What Do They Know?

    A deep-dive introduction to CSS container queries

    by Miriam Suzanne

    Past
    • – Sydney, Australia

      Web Directions Developer Summit

    • – Amsterdam, Netherlands

      CMD Amsterdam

    see all Talks & Workshops
  3. A gallery of numbered images in four columns
    Article post type

    Choosing a Masonry Syntax in CSS

    What makes something a ‘grid’, and what’s at stake?

    by Miriam Suzanne on

    Back in 2020, Firefox released a prototype for doing ‘masonry’ layout in CSS. Now all the browsers are eager to ship something, but there’s a hot debate about the best syntax to use.

    see all Article posts
  4. Article post type

    Partial Feature Queries, Relaxed Layout Containment, and More

    CSS Working Group updates from July

    by Miriam Suzanne on

    Over the last month, the CSS Working Group has determined we can loosen containment restrictions for query containers, and agreed on a syntax for special-case support queries (like support for the gap property in a flex context, or support for align-content in a block flow context).

    see all Article posts
  5. A stepped gradient of a pink hue in 2% lightness increments from 100% to 58%, labeled 'spec'
    Article post type

    CSS Working Group Updates for June & July

    What I’ve been working on as an Invited Expert

    by Miriam Suzanne on

    The CSS Working Group has regular face-to-face meetings (hybrid online/in-person) throughout the year, and they always result in a flurry of activity! Here’s a rundown of some highlights from the last few months, with a focus on the features I maintain.

    see all Article posts
  6. Video post type

    Smashing Hour with Miriam Suzanne

    on Smashing Hour with Miriam Suzanne on

    I joined Geoff Graham for a Smashing live stream to talk about CSS, web standards, music, and more!

    see all Video posts
  7. A back hoe on the bank of the Suez, trying to free the Ever Given cargo ship
    Article post type

    Learn Grid Now, Container Queries Can Wait

    Take your time with new CSS, but don’t sleep on the essentials

    by Miriam Suzanne on

    Several people have asked recently why container queries aren’t being used more broadly in production. But I think we underestimate the level of legacy browser support that most companies require to re-write a code-base.

    see all Article posts
  8. Video post type

    Web Development Is Theater

    on Work Item Podcast with Miriam Suzanne on

    I joined Den Delimarsky on the Work Item podcast to talk about my path as a developer – from building a website for my theater company, to building a career and a company around it. In this show, we talk about the power of the web, and how CSS is...

    see all Video posts
  9. A clear kitchen blender filled with chopped fruit and greens
    Article post type

    Can you un-mix a mixin?

    Rethinking the CSS mixin proposal after CSS Day

    by Miriam Suzanne on

    The CSS Working Group has agreed to move forward with CSS-native mixins. But some recent mixin-like CSS tricks have an advantage that the official proposal doesn’t account for: they make it easy to remove a mixin after it’s already been mixed in.

    see all Article posts
  10. Miriam about to say something on the Mechanical Ink podcast
    Podcast post type

    Collaboration, the Future of CSS, Sass, and the Web with Miriam Suzanne

    on Mechanical Ink with Miriam Suzanne on

    In this episode of the Mechanical Ink podcast, host Schalk Neethling sits down with Miriam Suzanne, a multifaceted expert in web development, an invited expert to the CSS Working Group, and a founder of OddBird.

    see all Podcast posts

2023

  1. Shop Talk Show Podcast
    Podcast post type

    Cascade Layers, CSS Functions, and More

    on Shop Talk Show with Miriam Suzanne on

    I drop by the show to talk about CSS updates and news on container queries, rolling out cascade layers, !important things to remember, custom properties, exit animations, CSS functions, state queries, and more.

    see all Podcast posts
  2. Video post type

    Demystifying CSS Container Queries

    on Learn With Jason with Miriam Suzanne on

    CSS Container Queries promise even more powerful styling approaches, but... what the heck are they? How do they actually work? Miriam joined Jason to teach and explore Container Queries in live code.

    see all Video posts
  3. Grainy art-deco illustration of a rocket launch
    Podcast post type

    CSS Containers

    A web development podcast from LogRocket

    on PodRocket with Miriam Suzanne on

    I talk with Noel Minchow about CSS Container Queries, why they took so long, how they work, and what to watch out for.

    see all Podcast posts
  4. The top front of a bright yellow shipping container with the door open and a blue sky behind it
    Article post type

    Can We Query the Root Container?

    The complexities of containment, overflow, and ‘propagation’

    by Miriam Suzanne on

    I spoke about Container Queries at both Smashing Conference (San Francisco) and CSS Day (Amsterdam) – where I recommended setting up a root container to replace most media queries. Since then, Temani Afif pointed out a few issues with that approach, and sent me down a rabbit hole of overlapping...

    see all Article posts
  5. Online Together Fall Summit 2021, October 11-13
    Talk post type

    Styling the Intrinsic Web

    With Cascade Layers & Container Queries

    by Miriam Suzanne

    Past
    • – Victoria, BC

      Camosun College

    • – San Francisco, CA

      SmashingConf SF

    see all Talks & Workshops

2022

  1. Wireframe of card elements in different sized containers -- some laid out vertically in small spaces, others horizontal when there's room.
    Talk post type

    Intrinsic CSS with Container Queries & Units

    by Miriam Suzanne

    Past
    • – San Francisco, CA (hybrid)

      Jamstack Conf

    • – Vancouver, Canada

      W3C Developer Meetup

    see all Talks & Workshops
  2. see all Article posts
    Wireframe of card elements in different sized containers -- some laid out vertically in small spaces, others horizontal when there's room.
    Article post type

    Use the Right Container Query Syntax

    Size queries are stable, and shipping in browsers

    by Miriam Suzanne on

    Since we got a first look at a Container Queries prototype back in April 2021, the syntax has changed a few times. But now the spec is stable, browsers are getting ready to ship, and it’s time to make sure you’re using the same syntax they are!

  3. Grainy art-deco illustration of a rocket launch
    Podcast post type

    Styling the intrinsic web

    A web development podcast from LogRocket

    on PodRocket with Miriam Suzanne on

    I talk with Noel Minchow about how to style the intrinsic web, what that means, and how it’s compatible with responsive design.

    see all Podcast posts
  4. A scene wipe transition in Star Wars, as Luke and C-3PO in a speeder wipe across a close-up of Luke and Obi-Wan talking. Over top, a dotted line shows the transition edge, and a red arrow shows the transition movement in front of the speeder.
    Article post type

    Every Transition is a Page Transition?

    Experimenting with the shared element transitions API

    by Miriam Suzanne on

    There’s a new web API proposal for transitioning shared-elements across pages. It’s great for making smooth page transitions, but what if we apply it to individual elements with changing styles on a single page?

    see all Article posts
  5. An image of the PostCSS Cascade Layers Plugin NPM package README including the version number, installation command, and a description of the package.
    Article post type

    Cascade Layers – There’s a Polyfill for That!

    by Sana Javed on

    Cascade layers are an exciting new addition to the CSS specification. A newly released polyfill now provides even greater browser support for the feature.

    see all Article posts
  6. Word Wrap Show
    Podcast post type

    Teleportation, PapayaWhip, and Cookies

    This episode went a little off the rails...

    on Word Wrap Show with Miriam Suzanne on

    I talk with Claire and Steph about changes to the Container Query syntax, our feelings about web components, named CSS colors, how much we like eating cookies, and other wild tangents.

    see all Podcast posts
  7. Video post type

    Making Sense of CSS Layers and Scope

    on Morten Rand-Hendriksen with Miriam Suzanne on

    CSS is evolving rapidly and new features come online all the time. Join Morten & Miriam to talk about what CSS layers and scope are all about and how they will change how we work with and think about the cascade in the future.

    see all Video posts
  8. see all Link posts
    fragment of an inverted triangle with the cascade -- cascade layers are highlighted below element-attached styles and above specificity
    Link post type

    A Complete Guide to CSS Cascade Layers

    Miriam Suzanne at CSS-Tricks on

    Cascade layers are a new CSS feature that allows us to define explicit contained layers of specificity, so that we have full control over which styles take priority in a project without relying on specificity hacks or !important. This guide is intended to help you fully understand what cascade layers are for, how and why you might choose to use them, the current levels of support, and the syntax.

2021

  1. Now What?
    Podcast post type

    Developing the Future of the Internet

    on Wix, Now What? with Miriam Suzanne on

    Miriam talks to Now What? about why the internet looks the way it does, why designers and developers need to collaborate and how the future of the web must be built around inclusivity and respect.

    see all Podcast posts
  2. Miriam Suzanne speaking at a conference
    Podcast post type

    What’s Happening in CSS & Sass

    on Front End Nerdery with Miriam Suzanne on

    A podcast focusing on front end development but also covering a wide range of web development and design topics. We talked about CSS, Sass, and work being done in the W3C CSS Working Group.

    see all Podcast posts
  3. Talk post type

    Container Queries & The Future of CSS

    Modernizing the cascade for responsive design systems

    by Miriam Suzanne

    Past
    • – Online

      Smashing Meets CSSummer

    • – Online

      CSS Café

    see all Talks & Workshops
  4. Back of a head, out of focus, looking at code
    Podcast post type

    Web Ecosystem Health Part VI

    on Igalia Chats with Miriam Suzanne on

    Igalia’s Brian Kardell sits down to chat with Miriam and Rachel Andrew about who works on standards, and who pays for that work.

    see all Podcast posts
  5. Syntax.
    Podcast post type

    CSS Container Queries, Layers, Scoping and More

    on Syntax.fm with Miriam Suzanne on

    In this episode of Syntax, Scott and Wes talk with Miriam about all things CSS – container queries, layers, scoping, and more!

    see all Podcast posts
  6. Word Wrap Show
    Podcast post type

    CSSWG, Container Queries, Scope, and Layers

    on Word Wrap Show with Miriam Suzanne on

    I talk with Claire and Steph about my journey into webdev and onto the CSSWG, what I find frustrating about how others use CSS, and the three specs I’m working on.

    see all Podcast posts
  7. A large, carved, wooden hand supporting a tree that has nearly fallen over
    Article post type

    Support (Not) Unknown

    Adding Container Query tests to CSS @support

    by Miriam Suzanne on

    Working on a new CSS feature like Container Queries, one of the most important considerations is to ensure a "migration path" – a way for developers to start integrating the new code, without breaking their sites on legacy browsers. That looks different depending on the feature, but can often include...

    see all Article posts
  8. F-Word
    Podcast post type

    Container Queries & the CSSWG

    on The F-Word with Miriam Suzanne on

    I chat with Bruce Lawson & Vadim Makeev about Sass & Susy, CSS Layers & compatibility, Container Queries, and the CSS Working Group.

    see all Podcast posts
  9. Smashing Podcast #36, Miriam Suzanne, What is the future of CSS?
    Podcast post type

    What Is The Future Of CSS?

    on Smashing Magazine with Miriam Suzanne on

    Starting a new season of the Smashing Podcast with a look at the future of CSS. What new specs will be landing in browsers soon? Drew McLellan talks to Miriam to find out.

    see all Podcast posts
  10. see all Article posts
    blockquote with magenta background and polygonal clip-path
    Article post type

    Container Queries: a Quick Start Guide

    Now is the time to begin experimenting with a long requested layout tool.

    by David A. Herron on

    The @container query, that elusive feature developers have been requesting and proposing for years, has finally made its debut in a browser. Well, sort of. Here we’ll explain what container queries are, how they work, and what other features they might come with once fully supported in browsers.

2020

  1. see all Article posts
    Article post type

    W3C Invited Expert on the CSS Working Group

    Helping define the future of styles on the web

    by Miriam Suzanne on

    I’ve joined the CSS Working Group as a W3C Invited Expert to help to develop the next level of Cascading & Inheritance, in addition to other CSS standards. I’m also currently active in the CSS4 and Design Token Community Groups.

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