nother of CSS’s boons is that you define things once, making it far more efficient than defining everything in HTML on every page. This means:

    Pages download faster, sometimes by as much as 50%
    You have to type less code, and your pages are shorter and neater.
    The look of your site is kept consistent throughout all the pages that work off the same stylesheet.
    Updating your design and general site maintenance are made much easier, and errors caused by editing multiple HTML pages occur far less often.