Who knows?

I love it when I come across some bit of CSS I’ve never heard of before.

Take this article on the text-emphasis property.

“The what property?”, I hear you ask. That was my reaction too. But look, it’s totally a thing.

Or take this article by David Bushell called CSS Button Styles You Might Not Know.

Sure enough, halfway through the article David starts talking about styling the button in an input type="file” using the ::file-selector-button pseudo-element:

All modern browsers support it. I had no idea myself until recently.

He’s right!

Then I remembered that I’ve got a file upload input in the form I use for posting my notes here on adactio.com (in case I want to add a photo). I immediately opened up my style sheet, eager to use this new-to-me bit of CSS.

I found the bit where I style buttons and this is the selector I saw:

button,
input[type="submit"],
::file-selector-button

Huh. I guess I did know about that pseudo-element after all. Clearly the knowledge exited my brain shortly afterwards.

There’s that tautological cryptic saying, “You don’t know what you don’t know.” But I don’t even know what I do know!

CSS or BS?

We show you a CSS property name. You tell us if it’s real or if we made it up. That’s it. It starts easy. It does not stay easy.

Progressive Web Components | Ariel Salminen

I’m slapping my forehead—progressive web components is a perfect name for what I’ve been calling HTML web components. Why didn’t I think of that?

A Progressive Web Component is a native Custom Element designed in two layers: a base layer of HTML and CSS that renders immediately, without JavaScript, and an enhancement layer of JavaScript that adds reactivity, event handling, and more advanced templating.

Performance-Optimized Video Embeds with Zero JavaScript – Frontend Masters Blog

This is a clever technique for a CSS/HTML only way of just-in-time loading of iframes using details and summary.

An in-depth guide to customising lists with CSS - Piccalilli

Think you know about styling lists with CSS? Think again!

This is just a taste of the kind of in-depth knowledge that Rich will be beaming directly into our brains at Web Day Out…

What’s new in web typography? | Clagnut by Richard Rutter

There have been so many advances in HTML, CSS and browser support over the past few years. These are enabling phenomenal creativity and refinement in web typography, and I’ve got a mere 28 minutes to tell you all about it.

I’ve been talking to Rich about his Web Day Out talk, and let me tell you, you don’t want to miss it!

It’s gonna be a wild ride! Join me at Web Day Out in Brighton on 12 March 2026. Use JOIN_RICH to get 10% off and you’ll also get a free online ticket for State of the Browser.