CSS I think!

I have a CSS file for my pages. HTML from scratch (just to learn the stuff and then when I can afford a wysywig tool). What I would like to do is get some other things into a common file so I have one place to edit them so when I replicate my main page for the others on the site (about 6 below the index.html) I do not have to go round them all. One example is the html for the horizontal nav bar, ul, li, etc. I'm probably missing something here. Can someone give me a lead. I played with dreamweaver once and this seemed to 'know' that other pages are affected and ask to update them.

This thread is now locked and can not be replied to.

Surface Pro (2017) vs Surface Pro 4

20 groundbreaking 3D animation techniques

How to mine Bitcoin on Mac