Thursday, January 15, 2009

Rounded Corners

When New WordPress started using this i though you know Internet Explorer is definitely out now when i'm doing some css work that needs rounded corners I'm mostly using only this technique because buyers are ok with it although it's just for FireFox and Safari. And since most of people still don't know about this i figured it's good thing to share.

Of course i'm talking about Border-radius property for FireFox and Safari 3 (only). And here are some nice examples how to use it.

#box { background: #eee; border: 1px solid #ccc; padding: 15px; -moz-border-radius: 10px; -webkit-border-radius: 10px; }

And of course you don't have to make all corners rounded, it can be just top left etc, so the code goes like this (small not, for example you can't make rounded corners on images and stuff like that)

* -moz-border-radius-topleft and -webkit-border-top-left-radius
* -moz-border-radius-topright and -webkit-border-top-right-radius
* -moz-border-radius-bottomleft and -webkit-border-bottom-left-radius
* -moz-border-radius-bottomright and -webkit-border-bottom-right-radius

CSS font shorthand rule

When styling fonts with CSS you may be doing this:
font-size: 1em;
line-height: 1.5em;
font-weight: bold;
font-style: italic;
font-variant: small-caps;
font-family: verdana,serif;

There's no need though as you can use this CSS shorthand property:
font: 1em/1.5em bold italic small-caps verdana,serif

Much better! Just a couple of words of warning: This CSS shorthand version will only work if you're specifying both the font-size and the font-family. Also, if you don't specify the font-weight, font-style, or font-varient then these values will automatically default to a value of normal, so do bear this in mind too.

Two classes together

Usually attributes are assigned just one class, but this doesn't mean that that's all you're allowed. In reality, you can assign as many classes as you like! For example:
class="text side"

Using these two classes together (separated by a space, not with a comma) means that the paragraph calls up the rules assigned to both text and side. If any rules overlap between the two classes then the class which is below the other in the CSS document will take precedence.

CSS border default value

When writing a border rule you'll usually specify the colour, width and style (in any order). For example, border: 3px solid #000 will give you a black solid border, 3px thick. However the only required value here is the border style.

If you were to write just border: solid then the defaults for that border will be used. But what defaults? Well, the default width for a border is medium (equivalent to about 3 to 4px) and the default colour is that of the text colour within that border. If either of these are what you want for the border then you can leave them out of the CSS rule!

!important ignored by IE

Normally in CSS whichever rule is specified last takes precedence. However if you use !important after a command then this CSS command will take precedence regardless of what appears after it. This is true for all browsers except IE. An example of this would be:
margin-top: 3.5em !important; margin-top: 2em

So, the top margin will be set to 3.5em for all browsers except IE, which will have a top margin of 2em. This can sometimes come in useful, especially when using relative margins (such as in this example) as these can display slightly differently between IE and other browsers.

(Many of you may also be aware of the CSS child selector, the contents of which IE ignores.)


When several selectors share the same declarations, they may be grouped into a comma-separated list.


In this example, we condense three rules with identical declarations into one. Thus,

H1 { font-family: sans-serif }
H2 { font-family: sans-serif }
H3 { font-family: sans-serif }

is equivalent to:

H1, H2, H3 { font-family: sans-serif }

CSS offers other "shorthand" mechanisms as well, including multiple declarations and shorthand properties.

Selector syntax

A simple selector is either a type selector or universal selector followed immediately by zero or more attribute selectors, ID selectors, or pseudo-classes, in any order. The simple selector matches if all of its components match.

A selector is a chain of one or more simple selectors separated by combinators. Combinators are: whitespace, ">", and "+". Whitespace may appear between a combinator and the simple selectors around it.

The elements of the document tree that match a selector are called subjects of the selector. A selector consisting of a single simple selector matches any element satisfying its requirements. Prepending a simple selector and combinator to a chain imposes additional matching constraints, so the subjects of a selector are always a subset of the elements matching the rightmost simple selector.

One pseudo-element may be appended to the last simple selector in a chain, in which case the style information applies to a subpart of each subject.



Here is a sample div with class "boxtest".

It has 20px border, 30px padding, and 300px width.

div.boxtest {
border:20px solid;
background: #ffc;

The total width including borders and padding should be 400px.

20+30+300+30+20 = 400

User agents which misinterpret the CSS1 box model by placing border and padding inside the specified width would result in a total width of only 300px, and a content width of only 200px.

300-20-30-30-20 = 200

The red and blue bars below are there for comparison. This div (including its borders) should be as wide as the blue bar.

Centre aligning a block element

you wanted to have a fixed width layout website, and the content floated in the middle of the screen. You can use the following CSS command.
width: 700px;
margin: 0 auto;