CSS ─ Syntax

CSS Syntax 

A CSS comprises of style rules that are interpreted by the browser and then applied to
the corresponding elements in your document. A style rule is made of three parts:

☹ Selector: A selector is an HTML tag at which a style will be applied. This could be
any tag like

or etc.
☹ Property: A property is a type of attribute of HTML tag. Put simply, all the HTML
attributes are converted into CSS properties. They could be color, border, etc.
☹ Value: Values are assigned to properties. For example, color property can have
the value either red or #F1F1F1 etc.

     You can put CSS Style Rule Syntax as follows:

selector { property: value }
Example: You can define a table border as follows:
table{ border :1px solid #C00; }
Here table is a selector and border is a property and the given value 1px solid #C00 is
the value of that property.

   You can define selectors in various simple ways based on your comfort. Let me put these
selectors one by one.
The Type Selectors
This is the same selector we have seen above. Again, one more example to give a color
to all level 1 headings:

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h1 { color: #36CFFF; }

The Universal Selectors

Rather than selecting elements of a specific type, the universal selector quite simply
matches the name of any element type:

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* { color: #000000; }

This rule renders the content of every element in our document in black.

The Descendant Selectors

Suppose you want to apply a style rule to a particular element only when it lies inside a
particular element. As given in the following example, the style rule will apply to
element only when it lies inside the

tag.

ul em {
 color: #000000;
}

The Class Selectors

You can define style rules based on the class attribute of the elements. All the elements
having that class will be formatted according to the defined rule.
.black {
 color: #000000;
}
This rule renders the content in black for only
elements with class attribute set to
black.
You can apply more than one class selectors to a given element. Consider the following
example:

This para will be styled by the classes center and bold.

The ID Selectors

You can define style rules based on the id attribute of the elements. All the elements
having that id will be formatted according to the defined rule.

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#black { color: #000000; }

This rule renders the content in black for every element with id attribute set to black in
our document. You can make it a bit more particular. For example:

h1#black {
 color: #000000;
}
This rule renders the content in black for only

elements with id attribute set

to black.
The true power of id selectors is when they are used as the foundation for descendant
selectors. For example:

#black h2 {
 color: #000000;
}
In this example, all level 2 headings will be displayed in black color when those headings
will lie within tags having id attribute set to black.
The Child Selectors
You have seen the descendant selectors. There is one more type of selector, which is
very similar to descendants but have different functionality. Consider the following
example:
body > p {
 color: #000000;
}
This rule will render all the paragraphs in black if they are a direct child of the
element. Other paragraphs put inside other elements like

or
would not have

any effect of this rule.

The Attribute Selectors

You can also apply styles to HTML elements with particular attributes. The style rule
below will match all the input elements having a type attribute with a value of text:
input[type="text"]{
 color: #000000;
}
The advantage to this method is that the element is
unaffected, and the color applied only to the desired text fields.

There are following rules applied to attribute selector.
 p[lang] - Selects all paragraph elements with a lang attribute.
 p[lang="fr"] - Selects all paragraph elements whose lang attribute has a value
of exactly "fr".
 p[lang~="fr"] - Selects all paragraph elements whose lang attribute contains
the word "fr".
 p[lang|="en"] - Selects all paragraph elements whose lang attribute contains

values that are exactly "en", or begin with "en-".