The selector is normally the HTML element you want to style.
Each declaration consists of a property and a value.
The property is the style attribute you want to change. Each property has a value.

CSS Example
A CSS declaration always ends with a semicolon, and declaration groups are surrounded by curly brackets:
p {color:red;text-align:center;}
To make the CSS more readable, you can put one declaration on each line, like this:
Example
p
{
color:red;
text-align:center;
}

CSS Comments
Comments are used to explain your code, and may help you when you edit the source code at a later date. Comments are ignored by browsers.
A CSS comment begins with "/*", and ends with "*/", like this:
/*This is a comment*/
p
{
text-align:center;
/*This is another comment*/
color:black;
font-family:arial;
}