Tags: css

1034

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Saturday, August 1st, 2020

this vs that - What is the difference between ___ and ___ in the front-end development?

A handy reference for explaining the differences between confusingly similar bits of HTML, CSS, and JavaScript.

Friday, July 31st, 2020

Smashing Podcast Episode 21 With Chris Ferdinandi: Are Modern Best Practices Bad For The Web? — Smashing Magazine

I really enjoyed this interview between Drew and Chris. I love that there’s a transcript so you can read the whole thing if you don’t feel like huffduffing it.

On the origin of cascades

This is a great talk by Hidde, looking at the history and evolution of cascading style sheets. Right up my alley!

Friday, July 24th, 2020

Pausing a GIF with details/summary | CSS-Tricks

This is such a clever and useful technique! It’s HTML+CSS only, and it’s a far less annoying way to display animated GIFs.

(Does anybody even qualify the word GIF with the adjective “animated” anymore? Does anyone know that there used to be such a thing as non-animated GIFs and that they were everywhere?)

MSEdgeExplainers/explainer.md at main · MicrosoftEdge/MSEdgeExplainers

This is great! Ideas for allowing more styling of form controls. I agree with the goals 100% and I like the look of the proposed solutions too.

The team behind this are looking for feedback so be sure to share your thoughts (I’ll probably formulate mine into a blog post).

Custom Property Coverup | Amber’s Website

This is a great bit of detective work by Amber! It’s the puzzling case of The Browser Dev Tools and the Missing Computed Values from Custom Properties.

Who do I know working on dev tools for Chrome, Firefox, or Safari that can help Amber find an answer to this mystery?

Thursday, July 23rd, 2020

CSS Vocabulary

This is a nifty visual interactive explainer for the language of CSS—could be very handy for Codebar students.

Saturday, July 18th, 2020

CSS photo effects - a Collection by Lynn Fisher on CodePen

These wonderfully realistic photo effects from Lynn are quite lovely!

Friday, July 10th, 2020

What is CSS Specificity? Sarah Chima - Front-End Developer

An excellent and clear explanation of specificity in CSS.

Tuesday, July 7th, 2020

Custom properties

I made the website for the Clearleft podcast last week. The design is mostly lifted straight from the rest of the Clearleft website. The main difference is the masthead. If the browser window is wide enough, there’s a background image on the right hand side.

I mostly added that because I felt like the design was a bit imbalanced without something there. On the home page, it’s a picture of me. Kind of cheesy. But the image can be swapped out. On other pages, there are different photos. All it takes is a different class name on that masthead.

I thought about having the image be completely random (and I still might end up doing this). I’d need to use a bit of JavaScript to choose a class name at random from a list of possible values. Something like this:

var names = ['jeremy','katie','rich','helen','trys','chris'];
var name = names[Math.floor(Math.random() * names.length)];
document.querySelector('.masthead').classList.add(name);

(You could paste that into the dev tools console to see it in action on the podcast site.)

Then I read something completely unrelated. Cassie wrote a fantastic article on her site called Making lil’ me - part 1. In it, she describes how she made the mouse-triggered animation of her avatar in the footer of her home page.

It’s such a well-written technical article. She explains the logic of what she’s doing, and translates that logic into code. Then, after walking you through the native code, she shows how you could use the Greeksock library to achieve the same effect. That’s the way to do it! Instead of saying, “Here’s a library that will save you time—don’t worry about how it works!”, she’s saying “Here’s it works without a library; here’s how it works with a library; now you can make an informed choice about what to use.” It’s a very empowering approach.

Anyway, in the article, Cassie demonstrates how you can use custom properties as a bridge between JavaScript and CSS. JavaScript reads the mouse position and updates some custom properties accordingly. Those same custom properties are used in CSS for positioning. Voila! Now you’ve got the position of an element responding to mouse movements.

That’s what made me think of the code snippet I wrote above to update a class name from JavaScript. I automatically thought of updating a class name because, frankly, that’s how I’ve always done it. I’d say about 90% of the DOM scripting I’ve ever done involves toggling the presence of class values: accordions, fly-out menus, tool-tips, and other progressive disclosure patterns.

That’s fine. But really, I should try to avoid touching the DOM at all. It can have performance implications, possibly triggering unnecessary repaints and reflows.

Now with custom properties, there’s a direct line of communication between JavaScript and CSS. No need to use the HTML as a courier.

This made me realise that I need to be aware of automatically reaching for a solution just because that’s the way I’ve done something in the past. I should step back and think about the more efficient solutions that are possible now.

It also made me realise that “CSS variables” is a very limiting way of thinking about custom properties. The fact that they can be updated in real time—in CSS or JavaScript—makes them much more powerful than, say, Sass variables (which are more like constants).

But I too have been guilty of underselling them. I almost always refer to them as “CSS custom properties” …but a lot of their potential comes from the fact that they’re not confined to CSS. From now on, I’m going to try calling them custom properties, without any qualification.

Friday, July 3rd, 2020

Dark mode revisited

I added a dark mode to my website a while back. It was a fun thing to do during Indie Web Camp Amsterdam last year.

I tied the colour scheme to the operating system level. If you choose a dark mode in your OS, my website will adjust automatically thanks to the prefers-color-scheme: dark media query.

But I’ve seen notes from a few friends, not about my site specifically, but about how they like having an explicit toggle for dark mode (as well as the media query). Whenever I read those remarks, I’d think “I’m really not sure I’ve got time to deal with adding that kind of toggle to my site.”

But then I realised, “Jeremy, you absolute muffin! You’ve had a theme switcher on your website for almost two decades now!”

Doh! I had forgotten about that theme switcher. It dates back to the early days of CSS. I wanted my site to be a demonstration of how you could apply different styles to the same underlying markup (this was before the CSS Zen Garden came along). Those themes are very dated now, but if you like you can view my site with a Zeldman theme or a sci-fi theme.

To offer a dark-mode theme for my site, all I had to do was take the default stylesheet, pull out the custom properties from the prefers-color-scheme: dark media query, and done. It took less than five minutes.

So if you want to view my site in dark mode, it’s one of the options in the “Customise” dropdown on every page of the website.

Uncommon CSS Properties

I count at least three clever CSS techniques I didn’t know about.

Sunday, June 28th, 2020

Friday, June 26th, 2020

Grid Cheatsheet

A useful resource for CSS grid. It’s basically the spec annoted with interactive examples.

Tuesday, June 23rd, 2020

CSS folded poster effect

This is a very nifty use of CSS gradients!

Saturday, June 13th, 2020

Striking a Balance Between Native and Custom Select Elements | CSS-Tricks

I think this a solution worthy of Solomon. In this case, the Gordian knot is the select element and its inevitable recreation in order to style it.

What if we instead deliver a native select by default and replace it with a more aesthetically pleasing one if possible? That’s where the “hybrid” select idea comes into action. It’s “hybrid” because it consists of two selects, showing the appropriate one at the right moment:

  • A native select, visible and accessible by default
  • A custom select, hidden until it’s safe to be interacted with a mouse

The implementation uses a genius combination of a hover media query and an adjacent sibling selector in CSS. It has been tested on a number of device/platform/browser combinations but more tests are welcome!

What I love about this solution is that it satisfies the stakeholders insisting on a custom component but doesn’t abandon all the built-in accessibility that you get from native form controls.

CSS Custom Properties Fail Without Fallback · Matthias Ott – User Experience Designer

Matthias has a good solution for dealing with the behaviour of CSS custom properties I wrote about: first set your custom properties with the fallback and then use feature queries (@supports) to override those values.

Thursday, June 11th, 2020

CSS custom properties and the cascade

When I wrote about programming CSS to perform Sass colour functions I said this about the brilliant Lea Verou:

As so often happens when I’m reading something written by Lea—or seeing her give a talk—light bulbs started popping over my head (my usual response to Lea’s knowledge bombs is either “I didn’t know you could do that!” or “I never thought of doing that!”).

Well, it happened again. This time I was reading her post about hybrid positioning with CSS variables and max() . But the main topic of the post wasn’t the part that made go “Huh! I never knew that!”. Towards the end of her article she explained something about the way that browsers evaluate CSS custom properties:

The browser doesn’t know if your property value is valid until the variable is resolved, and by then it has already processed the cascade and has thrown away any potential fallbacks.

I’m used to being able to rely on the cascade. Let’s say I’m going to set a background colour on paragraphs:

p {
  background-color: red;
  background-color: color(display-p3 1 0 0);
}

First I’ve set a background colour using a good ol’ fashioned keyword, supported in browsers since day one. Then I declare the background colour using the new-fangled color() function which is supported in very few browsers. That’s okay though. I can confidently rely on the cascade to fall back to the earlier declaration. Paragraphs will still have a red background colour.

But if I store the background colour in a custom property, I can no longer rely on the cascade.

:root {
  --myvariable: color(display-p3 1 0 0);
}
p {
  background-color: red;
  background-color: var(--myvariable);
}

All I’ve done is swapped out the hard-coded color() value for a custom property but now the browser behaves differently. Instead of getting a red background colour, I get the browser default value. As Lea explains:

…it will make the property invalid at computed value time.

The spec says:

When this happens, the computed value of the property is either the property’s inherited value or its initial value depending on whether the property is inherited or not, respectively, as if the property’s value had been specified as the unset keyword.

So if a browser doesn’t understand the color() function, it’s as if I’ve said:

background-color: unset;

This took me by surprise. I’m so used to being able to rely on the cascade in CSS—it’s one of the most powerful and most useful features in this programming language. Could it be, I wondered, that the powers-that-be have violated the principle of least surprise in specifying this behaviour?

But a note in the spec explains further:

Note: The invalid at computed-value time concept exists because variables can’t “fail early” like other syntax errors can, so by the time the user agent realizes a property value is invalid, it’s already thrown away the other cascaded values.

Ah, right! So first of all browsers figure out the cascade and then they evaluate custom properties. If a custom property evaluates to gobbledygook, it’s too late to figure out what the cascade would’ve fallen back to.

Thinking about it, this makes total sense. Remember that CSS custom properties aren’t like Sass variables. They aren’t evaluated once and then set in stone. They’re more like let than const. They can be updated in real time. You can update them from JavaScript too. It’s entirely possible to update CSS custom properties rapidly in response to events like, say, the user scrolling or moving their mouse. If the browser had to recalculate the cascade every time a custom property didn’t evaluate correctly, I imagine it would be an enormous performance bottleneck.

So even though this behaviour surprised me at first, it makes sense on reflection.

I’ve probably done a terrible job explaining the behaviour here, so I’ve made a Codepen. Although that may also do an equally terrible job.

(Thanks to Amber for talking through this with me and encouraging me to blog about it. And thanks to Lea for expanding my mind. Again.)

Saturday, June 6th, 2020

Hybrid positioning with CSS variables and max() – Lea Verou

Yet another clever technique from Lea. But I’m also bookmarking this one because of something she points out about custom properties:

The browser doesn’t know if your property value is valid until the variable is resolved, and by then it has already processed the cascade and has thrown away any potential fallbacks.

That explains an issue I was seeing recently! I couldn’t understand why an older browser wasn’t getting the fallback I had declared earlier in the CSS. Turns out that custom properties mess with that expectation.

Monday, June 1st, 2020

Global and Component Style Settings with CSS Variables — Sara Soueidan

Sara shares how she programmes with custom properties in CSS. It sounds like her sensible approach aligns quite nicely with Andy’s CUBE CSS methodology.

Oh, and she’s using Fractal to organise her components:

I’ve been using Fractal for a couple of years now. I chose it over other pattern library tools because it fit my needs perfectly — I wanted a tool that was unopinionated and flexible enough to allow me to set up and structure my project the way I wanted to. Fractal fit the description perfectly because it is agnostic as to the way I develop or the tools I use.