CSS is something which customises the appearance of your web page. As many attributes are becoming deprecated, for a valid website, you will have to use CSS to customise the appearance of it.
There are loads of selectors to use, so I will list the most common ones in another post.
CSS is a style. It can be a style sheet or as an attribute.
Internal Style sheets
Style sheets can be put directly into your HTML document as an internal style sheet.
The <style> tag is used if you want to put an internal style sheet into your HTML document. These are always placed inside the head section.
Remember to put the type attribute in the <style> tags. So it would look like <style type="text/css">
e.g.
<html> <head> <style type="text/css"> /*Your style sheet goes here*/ </style> </head> <body> Content in here. </body> </html>
External Style sheets
If you don’t want to have an internal style sheet because it may be a large file or you just want to keep it organised. You can save your style sheet as a separate file, with the extension .css.
Use this tag:
<link rel="stylesheet" type="text/css" href="stylesheet.css">
And place it in the head section. Remember to change the stylesheet.css to what your style sheet is called (make sure you leave the .css on).
Style Attribute
Style attributes is a inline style for an element.
You just place the attribute: style="value" in the tag you want it to change.
e.g.
<h1 style="color:pink">Some example text</h1>
![:]](http://jammy.party-truffle.net/wordpress/wp-includes/images/smilies/kao_regular.gif)
And that’s okay, I’m trying to think of something too 
A tutorial, uhm? I should take some time to think about...