there are 3 ways to declare CSS styles
1. External - when you create a separate file of CSS Styles and you include (link) it to the page. It is recommended that it be placed inside the <head></head> tags, however it will be recognized if placed elsewhere in the file.
<head>
<link type="text/css" rel="stylesheet" href="/path/to/file.css" media="all">
</head>
2. Embed - when you create a stylesheet inside the page that will display it. It is recommended that it be placed inside the <head></head> tags, however it will be interpreted if declared anywhere in the page.
<head>
<style type="text/css" media="all">
body {
margin: 0;
padding: 0;
background: #hexadecimal url('/path/to/image.gif') repeat top left;
color: #hexadecimal;
}
</style>
</head>
3. Inline - CSS Styles that are declared within the tag that they will affect. These styles will not affect any other styles but the one they are declared within (persay - if you change a CSS property that effects the width and height of the element than surrounding tags will be affected, indirectly)
<div style="background-color: #000000; color: #ffffff">BLACK BACKGROUND, WHITE TEXT</div>
White space inside the style declaration should not make a difference, in theory (can never count on IE handling something properly) The way I have declared these styles are typical syntactical layout, however there are no standards on exactly how something must be written (in terms of whitespace / alignment). Clients / Employers however, may suggest or enforce a coding technique or style guide when composing computer code