Cascading Style Sheets are used to define the presentation layer of websites. How CSS works is not always self-evident, so many of these articles explain various aspects of using CSS.
Hiding content with display:none hides it from all users, including those who use screen readers. Be aware of this when deciding how to hide content visually.
The Book of CSS3 is a great developer companion - a no-nonsense, well-written guide to the various specifications that make up CSS3.
In this brief and easy-to-read book, Aaron Gustafson does an excellent job of explaining what progressive enhancement is and how to apply it in your daily work.
Ethan Marcotte’s book on designing for an ever-increasing variety of browsers, resolutions and screen sizes is a must-read for all web professionals.
Some browsers don’t let you center button elements horizontally by assigning auto margins. Bug or not?
How to use generated content to style the numbers of an ordered list separately from the rest of the list item.
Sometimes you may find that a design forces you to clip content. Fortunately CSS3 offers a way of indicating that text has been clipped.
The CSS3 box-sizing property can be incredibly useful when you want flexible widths on elements that also have padding and/or borders. And browser support is rather good.
The Flexible Box Layout Model allows us to align and distribute boxes vertically and horizontally as well as have boxes flex to use all available space.
Using CSS to change the display order of content without also changing the order in the HTML source can cause accessibility issues and should be avoided.
Using display:table to center a page layout vertically works in most browsers. There is an unfortunate issue with some screenreaders to be aware of though.
Explanations of why some of the bad practices that are made fun of at the Enterprise CSS/HTML/JS sites are bad practices.
The W3C CSS Validator is about to add an option where you can choose to have vendor-specific extensions reported as warnings rather than errors, making it easier to find real errors in your CSS.
WebKit-based browsers do not include vertical scrollbars in the viewport width, which goes against the Media Queries specification and differs from Firefox and Opera.
For em-based layouts, using ems to specify column widths can cause problems when text size is increased. Using percentages for columns width is often a better choice.
When using @font-face with typefaces that have multiple weights and styles it’s important to do it correctly, or your CSS will become unwieldy and browsers will have no fallback styles.
How to prevent your website from having unreadably small text when it is first loaded in Safari on iOS and how to prevent auto-scaling of text when you change orientation from portrait to landscape on your iPhone/iPod/iPad
Older versions of YUI Compressor have a bug that makes some media queries malformed after minifying, causing browsers to skip the rules within. There is a fix though.
A tutorial that explains how to use the CSS float property to create layouts with three or more columns.
Think very carefully before using -webkit-text-size-adjust:none since it will prevent people using WebKit-based browsers from resizing text. Needless to say, that is not user-friendly.