Tags: properties

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Monday, July 1st, 2019

8 DOM features you didn’t know existed - LogRocket Blog

If you ignore the slightly insulting and condescending clickbaity title, this is a handy run-down of eight browser features with good support:

  1. extra arguments in addEventListener(),
  2. scrollTo(),
  3. extra arguments in setTimeout() and setInterval(),
  4. the defaultChecked property for checkboxes,
  5. normalize() and wholeText for strings of text,
  6. insertAdjacentElement() and insertAdjacentText(),
  7. event.detail, and
  8. scrollHeight and scrollWidth.

Wednesday, May 22nd, 2019

Making Future Interfaces: Custom Properties - YouTube

Heydon cracks me up—his Patterns Day is going to have you crying with laughter; guaranteed!

Here he is talking about custom properties in CSS as part of his Making Future Interfaces video series.

Friday, May 3rd, 2019

Create a responsive grid layout with no media queries, using CSS Grid - Andy Bell

CSS grid and custom properties really are a match made in heaven.

Thursday, April 18th, 2019

Inlining SVG background images in CSS with custom properties

Here’s a tiny lesson that I picked up from Trys that I’d like to share with you…

I was working on some upcoming changes to the Clearleft site recently. One particular component needed some SVG background images. I decided I’d inline the SVGs in the CSS to avoid extra network requests. It’s pretty straightforward:

.myComponent {
    background-image: url('data:image/svg+xml;utf8,<svg> ... </svg>');
}

You can basically paste your SVG in there, although you need to a little bit of URL encoding: I found that converting # to %23 to was enough for my needs.

But here’s the thing. My component had some variations. One of the variations had multiple background images. There was a second background image in addition to the first. There’s no way in CSS to add an additional background image without writing a whole background-image declaration:

.myComponent--variant {
    background-image: url('data:image/svg+xml;utf8,<svg> ... </svg>'), url('data:image/svg+xml;utf8,<svg> ... </svg>');
}

So now I’ve got the same SVG source inlined in two places. That negates any performance benefits I was getting from inlining in the first place.

That’s where Trys comes in. He shared a nifty technique he uses in this exact situation: put the SVG source into a custom property!

:root {
    --firstSVG: url('data:image/svg+xml;utf8,<svg> ... </svg>');
    --secondSVG: url('data:image/svg+xml;utf8,<svg> ... </svg>');
}

Then you can reference those in your background-image declarations:

.myComponent {
    background-image: var(--firstSVG);
}
.myComponent--variant {
    background-image: var(--firstSVG), var(--secondSVG);
}

Brilliant! Not only does this remove any duplication of the SVG source, it also makes your CSS nice and readable: no more big blobs of SVG source code in the middle of your style sheet.

You might be wondering what will happen in older browsers that don’t support CSS custom properties (that would be Internet Explorer 11). Those browsers won’t get any background image. Which is fine. It’s a background image. Therefore it’s decoration. If it were an important image, it wouldn’t be in the background.

Progressive enhancement, innit?

Wednesday, March 20th, 2019

CSS custom properties in generated content

Cassie posted a neat tiny lesson that she’s written a reduced test case for.

Here’s the situation…

CSS custom properties are fantastic. You can drop them in just about anywhere that a property takes a value.

Here’s an example of defining a custom property for a length:

:root {
    --my-value: 1em;
}

Then I can use that anywhere I’d normally give something a length:

.my-element {
    margin-bottom: var(--my-value);
}

I went a bit overboard with custom properties on the new Patterns Day site. I used them for colour values, font stacks, and spacing. Design tokens, I guess. They really come into their own when you combine them with media queries: you can update the values of the custom properties based on screen size …without having to redefine where those properties are applied. Also, they can be updated via JavaScript so they make for a great common language between CSS and JavaScript: you can define where they’re used in your CSS and then update their values in JavaScript, perhaps in response to user interaction.

But there are a few places where you can’t use custom properties. You can’t, for example, use them as part of a media query. This won’t work:

@media all and (min-width: var(--my-value)) {
    ...
}

You also can’t use them in generated content if the value is a number. This won’t work:

:root {
    --number-value: 15;
}
.my-element::before {
    content: var(--number-value);
}

Fair enough. Generated content in CSS is kind of a strange beast. Eric delivered an entire hour-long talk at An Event Apart in Seattle on generated content.

But Cassie found a workaround if the value you want to put into that content property is numeric. The CSS counter value is a kind of generated content—the numbers that appear in front of ordered list items. And you can control the value of those numbers from CSS.

CSS counters work kind of like variables. You name them and assign values to them using the counter-reset property:

.my-element {
    counter-reset: mycounter 15;
}

You can then reference the value of mycounter in a content property using the counter value:

.my-element {
    content: counter(mycounter);
}

Cassie realised that even though you can’t pass in a custom property directly to generated content, you can pass in a custom property to the counter-reset property. So you can do this:

:root {
    --number-value: 15;
}
.my-element {
    counter-reset: mycounter var(--number-value);
    content: counter(mycounter);
}

In a roundabout way, this allows you to use a custom property for generated content!

I realise that the use cases are pretty narrow, but I can’t help but be impressed with the thinking behind this. Personally, I would’ve just read that generated content doesn’t accept custom properties and moved on. I would’ve given up quickly. But Cassie took a step back and found a creative pass-the-parcel solution to the problem.

I feel like this is a hack in the best sense of the word: a creatively improvised solution to a problem or limitation.

I was trying to display the numeric value stored in a CSS variable inside generated content… Turns out you can’t do that. But you can do this… codepen.io/cassie-codes/p… (not saying you should, but you could)

Sunday, January 13th, 2019

The Flexbox Holy Albatross | HeydonWorks

Er …I think Heydon might’ve cracked it. And by “it”, I mean container queries.

This is some seriously clever thinking involving CSS custom properties, calc, and flexbox. The end result is a component that can respond to its container …and nary a media query in sight!

Friday, January 11th, 2019

Stepping away from Sass

I think Cathy might’ve buried the lede:

The knock on effect of this was removing media queries. As I moved towards some of the more modern features of CSS the need to target specific screen sizes with unique code was removed.

But on the topic of Sass, layout is now taken care of with CSS grid, variables are taken care of with CSS custom properties, and mixins for typography are taken care of with calc().

Personally, I’ve always found the most useful feature of Sass to simply be that you can have lots of separate Sass files that get combined into one CSS file—very handy for component libraries.

Saturday, November 17th, 2018

Difference between currentColor & Custom Properties | Mike Riethmuller

I had to read through this twice, but I think I get it now (I’m not the sharpest knife in the drawer). Very useful if you’re doing theming in CSS.

Tuesday, August 21st, 2018

A Tale of Two Buttons

In defence of the cascade (especially now that we’ve got CSS custom properties).

I think embracing CSS’s cascade can be a great way to encourage consistency and simplicity in UIs. Rather than every new component being a free for all, it trains both designers and developers to think in terms of aligning with and re-using what they already have.

Remember, every time you set a property in CSS you are in fact overriding something (even if it’s just the default user agent styles). In other words, CSS code is mostly expressing exceptions to a default design.

Tuesday, May 29th, 2018

Dark theme in a day – Marcin Wichary – Medium

On Ev’s blog, Marcin goes into great detail on theming an interface using CSS custom properties, SVG, HSL, and a smattering of CSS filters.

I was kind of amazed that all of this could happen via CSS and CSS alone: the colours, the transitions, the vectors, and even the images.

Saturday, May 19th, 2018

Super-powered layouts with CSS Variables + CSS Grid by Michelle Barker on CodePen

This article is about using custom properties and CSS grid together, but I think my favourite part is this description of how custom properties differ from the kind of variables you get from a preprocessor:

If you’re familiar with Javascript, I like to think of the difference between preprocessor variables and CSS Variables as similar to the difference between const and let - they both serve different purposes.

Wednesday, March 7th, 2018

Parallax scrolling with CSS variables | basicScroll

Don’t let the title fool you—this isn’t just for parallax scrolling (thank goodness!)—it’s for triggering any CSS updates based on scroll position. Using CSS custom properties makes a lot of sense. The JavaScript/CSS bridge enabled by custom properties is kind of their superpower. (That’s one of the reasons why I don’t like calling them “CSS variables” which makes them sound like Sass variables—they’re so much more than that!)

Thursday, December 7th, 2017

CSS usage on the web platform - Microsoft Edge Development

Top of the props.

CSS properties …props …top of the. Never mind.

This CSS usage data comes from a Bing-powered scan of 2,602,016.00 pages.

Friday, August 4th, 2017

CSS: Current, Soon, Someday (Web Directions Code 2017) // Speaker Deck

Oh, how I wish I could’ve been at Web Directions Code in Melbourne to see this amazing presentation by Charlotte. I can’t quite get over how many amazing knowledge bombs she managed to drop in just 20 minutes!

Thursday, July 20th, 2017

0825 — ericportis.com

Well, well, well …following on from my post about container queries, it turns out that Eric has also been thinking about wrangling custom properties. He’s even written some code.

Thursday, June 22nd, 2017

Using CSS variables correctly - Mike Riethmuller

Mike examines the real power of CSS custom properties compared to Sass variables—they can change at runtime.

I’m convinced that in almost all cases, responsive design logic should now be contained in variables. There is a strong argument too, that when changing any value, whether in a media query or an element scope, it belongs in a variable. If it changes, it is by definition a variable and this logic should be separated from design.

Tuesday, May 23rd, 2017

Learn CSS Grid - A Guide to Learning CSS Grid | Jonathan Suh

A quick visual guide to CSS Grid properties and values.

Tuesday, April 18th, 2017

Organize your CSS properties however you dang like – Michael.blog

Neither matters all that much and you can use every method on the same project without the universe imploding.

Some interesting approaches in the comments too.

Saturday, April 15th, 2017

The invisible parts of CSS · MadebyMike

This is a really clear explanation of how CSS works.

Monday, November 28th, 2016

CSS Reference - A free visual guide to the most popular CSS properties.

A whole lotta CSS properties and values gathered together in one place. The one-page view is a bit overwhelming, but search and collections can get you to the right bit lickety-split.