Before 1995, every page needed to be designed and many designers would have to copy the same template over and over, creating individual HTML pages that looked similar, or might be different, all hand coded into the templates themselves. This could easily number into the hundreds to thousands of individual page creation, which would eventually give rise to DHTML, or Dynamic HTML, and then ultimately, to the CMS, or Content Management Systems, where pages could be loaded through database calls and eventually, a caching system, for fastest loading speed times.
The result being that instead of creating hundreds to thousands of pages individually, you could load a single page every time and a call to a database for that web page would load up the content, eliminating the physical need of page creation. Once CSS, or Cascading Style Sheets, came to full adoption by the entire web community, it made things much easier, as pages could look the same in a single line of code. The beauty of CSS was that you could still place CSS inline to change templates while still having the general template look like every other page.