Jeromy D. answered 06/21/19
Husband, father, actor and speaker
Highly recommend starting with a Framework. This is the most popular route:
https://themes.getbootstrap.com/ - this gives you ALL the code (CSS, HTML5, JS) as a framework to build out and expand upon. Will save you thousands of hours of needless work (and your code will be 100x better) and it's free
An even better route is to setup Wordpress (www.wordpress.org) so your or the client can manage and maintain updates 100x easier in the future.