PUBLIC MARKS from decembre with tags css-tricks & tutoriel

The :target pseudo selector in CSS matches when the hash in the URL and the id of an element are the same.

The following is a guest post by Parker Bennett. Parker has written for CSS-Tricks before, in his article Crop Top dealing with the positioning of fluid images. This is a great follow up to that, presenting another option in the never-ending responsive images saga. It's also an interesting contrast to yesterday's post on responsive images - so you can see how very different the approaches to this problem can be.

When it comes to centering things in web design, the more information you have about the element being centered and its parent element, the easier it is. So what if you don't know anything? It's still kinda doable.

If you know the exact width/height of an element, you can center it smack dab in the middle of its parent element easily with this classic trick: top and left set to 50% and negative margins half the width and height of the element. That's great if you know the width and height of the element you're trying to center, but what if they are percentages?