Cascading Style Sheet (css)

On these pages I am using CSS level 2

Using a style sheet can Save a lot of work (I am lazy and so make use of CSS)

There are 2 main ways you can use CSS,
add individual CSS code to each page, in the head tags or inline code
or use a independent CSS page

My preferred way is to use independent CSS page, and call it using,
<LINK rel="stylesheet" href="delta.css" type="text/css">
this strip of code resides between the head tags.

This site uses CSS, altering one CSS page will alter the whole site,
this saves a lot of time, imagine having a site with 100+ pages and wanting to alter text colour,
I just alter delta.css and my site then has text in a new colour, as opposed to altering 100 pages.

You say but I want this page text in a different colour, no problem
you can add a style to the page to alter that page,
my preferred method is to use a class within main CSS page.

The advantages of CSS is you remove clutter in your code
Font size this, font color that, font style the other, bold,

Example of CSS in Page Design
Here