• 200914 Apr

    So, the CSS Working Group is trying to wrap up the CSS3 Backgrounds and Borders Module and prepare it for Last Call. However, there are still some open issues we’d would like to get comments on.

    Most of the open issues revolve around border-image. Brad Kemper knocked down several with his proposal and the CSS Working Group has adopted it in principle. (You can find it drafted into the latest unofficial Editor’s Draft on the W3C site.) We’re still ironing out the details on that, but there are a few others still open on border-image:

    First Issue: Several people have commented that they would like a way to clip out the center part of the image. There are two options for this: A) Keep the middle part by default (current behavior). Add an empty keyword that clips out the middle part. B) Make the middle part clip out by default. Add a fill keyword that keeps it. (It’s needed for stretch-tiling things like aqua buttons.) Of course we might also just keep the current solution, C) have authors make that part of the image transparent. Comments? What would you use?

    Second Issue: The syntax is particularly arcane. One commenter suggested breaking up border-image into multiple properties, leaving border-image itself as a shorthand. For example,

    border-image: url(...) 20% 40% / 10% 4em 20% / 0 1em;

    would be equivalent to

    border-image-source: url(...);
    border-image-slice: 20% 40%;
    border-image-widths: 10% 4em 20%;
    border-image-outset: 0 1em;

    This would also allow the values to cascade independently, making it easy to e.g. swap just the image. There’s an overhead cost to more properties, however, so if we do this there needs to be a significant and useful advantage. Thoughts on this idea, or any other ideas for making border-image easier to understand?

    Third Issue: There’s still an open question of how border-image should interact with box-shadow. The two proposals on the table are: 1.) Ignore box-shadow when border-image is in effect. (The author can draw the shadow directly in the border-image.) 2.) Use the border-image as a mask to draw a shadow, but only draw the shadow where it appears outside the padding edge (inner border edge). Comments? Preferences?

    Fourth Issue: The next topic is fallback colors: the current draft has a feature that lets you specify a background color to use only if the bottommost background image fails to load. The WG wants to know, is this feature something authors really want? Several WG members have posted comments saying that it’s too hard to understand, that it’s not useful, and that the proposed syntax doesn’t make sense. What do you think?

    Fifth Issue: The last issue is, the current draft specifies a background-clip: no-clip feature that lets a background image spill out of the border box. Implementors are concerned that it’s tricky to implement, and aren’t convinced that it would be useful. If this is something you want, show off a realistic example or two that demonstrates why it is needed.

    Off-topic Issue: While I’m here, the WG wanted me to ask what people thought of renaming the block-progression property to block-flow or block-direction and whether either was more understandable (or if anyone had better ideas). The property changes the direction of block layout, and the values are tb (horizontal lines stacked top-to-bottom, like English text), rl (vertical lines stacked right-to-left, like traditional Chinese text), and lr (vertical lines stacked left-to-right). This is for vertical text layout, btw; it’s different from graphical rotation. See pages 2-5 of UTN 22 (PDF/HTML+SVG) for a definition.

    P.S. Could someone please fix the css3.info style sheet so it doesn’t effectively eat list markup? Thanks.

  • 200911 Apr

    The CSS Working Group had a face-to-face meeting in Tokyo last month and made a series of resolutions (which can be found on their blog). Most are fine technical points, but one of the more interesting is that the multi-column layout module is about to be reissued as a ‘last call’ document; after this, the module will be released as a candidate recommendation, meaning the authors are satisfied that the standard does what is needed of it, and will call for implementation.

    As you may know, Webkit browsers (Safari, Chrome, etc) already support multi-column declarations (with a -webkit- prefix) and Gecko browsers (Firefox, Camino, etc) partially support it (with a -moz- prefix) – and fuller support will be forthcoming in Firefox 3.5. With those implementations in place, I’m hopeful that it will pass quickly through the recommendation process and become a standard.

    Last week saw another layout proposal, the template layout module, reissued as an updated working draft. Previously known as the advanced layout module (and featured in our article How We’ll Lay Out Websites in 2016).

    As a quick reminder, template layouts allow you to assign content to ‘slots’, which can then be laid out by declaring a grid using alphabetical characters. The following code would set up a two row grid, with the top row spanning the three individual columns of the bottom row:

    body {

    You could then match elements to each slot by using pre-existing selectors and the position attribute:

    div#div1 { position: a; }
    div#div2 { position: b; }

    And also use the new slot pseudo-class to apply styles:

    body::slot(a) { border: 1px solid; }

    This is probably the most radical proposal since the CSS standard was first created, allowing for very flexible template layouts, and I’m quite excited about it. However, it currently has no implementation, so is doubtless a long way off. Perhaps my satirical date of 2016 is not too wide of the mark after all.

  • 200922 Mar

    An interesting implementation has recently made its way into the latest Webkit nightlies – a detailed method of styling scrollbars using a combination of new pseudo-elements and pseudo-classes.


    Although the new syntax can seem complicated at first, Webkits implementation gives authors the ability to completely alter the look and feel of scrollbars of overflow sections, listboxes, dropdown menus & textareas, and when used in conjunction with border-image and multiple backgrounds, the results can look beautiful.

    Whitepaper gives more details on the implementation.

  • 200921 Jan

    Believe it or not there still a lot of discussion around CSS 3. The concerns among designers/developers vary widely and we’ve found that our visitors use CSS3.info in many different ways.

    1. General questions about your CSS 3,
    2. Research for future-proofing your projects,
    3. Browser support issues and updates,
    4. Tutorials and how to’s on CSS 3 features,
    5. Goings on in the CSS world

    So there’s quite a range of information that we can get into and provide, but we would like some feedback from our readers so that we can continue to make the site a helpful resource.

    If you’ve done extensive work with CSS3, feel free to let us know via the contact form and perhaps you can provide us with a tutorial or review that we can feature on the site!

    Leave us a reply in the comments below and let us know what types of information you’d like to see us providing this year.

  • 200815 Nov

    There’s been an apparent need (voiced by the web community) for CSS-based Constants ever since the conception of CSS (even though there are many established server-side preprocessors in existance). From reading blogs and the like, people are either very much in favour or very much against the idea, but the feature’s mixed reception hasn’t stopped members of the CSSWG exploring and discussing the idea further, to the point where we now have two fairly detailed proposals from members of the Working Group. The aim of this post is to explore and then summarise the current state of both proposals (from an authors not a vendors point of view), comparing features of both.

    Back in March this year, Dave Hyatt and Daniel Glazman combined forces and presented the first formal proposal for Variables to the Working Group, and (based on this spec) Hyatt subsequently implemented the module into Webkit nightlies; the implementation was distributed for around 5 months, but was later removed due to concerns regarding feature adoption by authors before the spec had any time to mature. In August this year, fantasai submitted a counter-proposal which detailed plans for a parse-time syntax for Constants (which are lost after the variables are parsed and therefore not mutable), compared to Hyatt’s/Glazman’s proposal which allowed for scriptable Variables.

    Types of Constants

    Fantasai’s proposal features three types of named Constants, ‘values’, ‘style-sets’ and ‘selectors’; a value constant represents a property value, a style-set constant represents one or more property declarations and a selector constant represents a selector. Each are declared using an @define rule and as fantasai explains, the syntax of an @define rule is the @define at-keyword, followed by either the values keyword (for declaring value constants) or the style-sets keyword (for declaring style-set constants) or the selectors keyword (for declaring selector constants), followed by a block. Examples (ripped straight from her proposal :)) showing the syntax for each of the three Constants are below:-


    @define values { textColor: black; bgColor: white; accentColor: silver; accentBorder: double silver 5px; }


    define style-sets { noteBox { border-style: solid; padding: 1em; border-radius: 1em; } quoteBox { margin: 1em; } }

    A feature of fantasai’s proposal is that constants are re-usable, so you can include ‘style-set templates’ which can be applied to multiple selector declarations, using different value constant values.


    Note that any selectors used in such a variable aren’t allowed to be grouped (using the comma-seperated grouping syntax), since we will have the ability to group selector variables anyway. Selector constants would be useful for repeatedly selecting child/grandchild etc elements deep within a complex DOM tree; consider this:-

    @define selectors { deeplynestedelement: body.home > div#main.container ~ ul#navigation > li a[href="http"] span#child > span#imrunningoutofnames;}
    deeplynestedelement u, deeplynested b{ color:red; }

    And with the addition of a possible :match() pseudo class in Selectors Level 4, you could do something like this to make the above statement even more organised:-

    deeplynestedelement:matches(u,b){ color:red; }

    Instead Hyatt’s/Glazman’s proposal simply utilises a new @variables rule in which any type of variable (presumably) can be used, without the need for type keywords – their proposal isn’t actually clear on whether different types of variables can be parsed (or whether this proposal simply targets value constants), however, after looking at several test cases, the implementation seems like it was capable of at least parsing ‘style-sets’ constants too.

    @variables { CorporateLogoBGColor: #fe8d12; }

    div.logoContainer { background-color: var(CorporateLogoBGColor); }


    Two fairly major differences between the two proposals are their scoping behaviour. In fantasai’s proposal, by default, the scope of a named constant does not ordinarily cross @import boundaries; this essentially means that the use of variables declared in one @import are restricted to that particular stylesheet, unlike Hyatt’s/Glazman’s proposal where, by default, constants cross @import boundaries. However, using fantasai’s proposal, authors do have complete control over the scope by using one of three new keywords (which is placed between the @import keyword and the stylesheet URI), push, pull and sync; pull allows constants declared within the imported stylesheet to be used in the importing stylesheet; push allows constants declared above the @import rule in the importing style sheet to be used the imported style sheet; sync allows both of the previous, simultaneously.

    The two proposals differ also in the way that constants relate to, and work with Media Types. In Hyatt’s/Glazman’s proposal, an optional Media Type keyword can be placed between the @variables keyword and succeeding block declaration. In fantasais proposal, constant declarations (placed within a @define block) can be nested within an @media block. However she metions, …if declared inside an @media rule, the scope of the declaration does not end with the @media block, meaning that constants can be used outside of the @media they’re placed in. It’s worth mentioning that the @media rule model/syntax differences could be trivially modified to use the other’s media type syntax.

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