CSS allows you to define global styles, or formatting choices (font style, text color, background color, etc) and apply those styles to all the pages within a website without having to repeatedly write the code into the HTML document. It saves lots of time during the initial design of a site, ensures the pages have a universal look and feel, and makes it incredibly easy to update the format of an entire website.
For example, if Amazon.com, which has thousands of individual web pages, did not use CSS and wanted to change their font from Arial to Helvetica, their design team would have to open and modify each of those thousand of pages individually. Using CSS, however, they simply change one line of code in the CSS document and every page will display the new font.
CSS was developed to help designers separate code that specifically is used solely for the presentation of content from the content and markup. It allows designers to declare a rule once and use it on multiple pages or multiple times on the same page without having to re-declare the rule every time you use it. This was a big deal when it came out because designers were finally able to writer leaner and cleaner code that was easier to read and follow, and making a style change didn't require you to change it hundreds of times, with CSS you change it once in one place and your done.
CSS is important because it allows you to fully separate the bare bones structure of your website (HTML) from the stying (CSS). This means that your code will be cleaner and easier to understand.
It was initially defined in the late 1990s as a way to separate the HTML content from the presentation. One stylesheet could be used for many pages. One page could have more than one stylesheet as well and precedence then takes over.
Cascading Style Sheets, commonly referred to as CSS, was developed by the World Wide Web Consortium (W3C).
It was created for programmers to change the style of websites and HTML
To separate content from layout, making editing and formatting much easier.
CSS Beaufort was created on 1861-07-09.
CSS Acadia was created on 1917-01-16.
CSS Tallahassee was created on 1864-07-20.
Valid CSS is CSS that has been run through the W3C CSS checker and passed.
CSS
CSS Teaser was created in 1862.
CSS Ellis was created in 1861.
CSS Webb was created in 1865.
CSS Hampton was created in 1862.
CSS Industries was created in 1923.
CSS Appomattox was created in 1861.
CSS Columbia was created in 1864.
CSS Drewry was created in 1863.
CSS Chickamauga was created in 1864.
CSS Corp was created in 1996.
CSS Charleston was created in 1863.
CSS Resolute was created in 1861.