CSS is a bunch of goop you add as well to make HTML behave the way you want - it sets "styles" and you can manipulate nearly every aspect of HTML by using css. The concept is fairly simple, but the implementation is possibly the most arcane in the entire suite of web languages. It has problems with sytax and semantics. An obvious addition would be intelligence, this was done 30 years ago and it called "postscript" which would also obviate the need for JavaScript and HTML. Plus it's faster, smaller and does way more things. Every document processing and desktop publishing system ever written can output postscript which printers, screen viewers and professorial typesetting equipment alike recognize by virtue of the fact it's the only open standard besides raw txt files. Good luck, it's a nightmare. See also online CSS3 generator tools

And: http://caniuse.com to see what works in what browser..

ref CSS to CSS3 01 Introduction 02 Selectors 03 Gradients 04 Color 05 Div 06 Background 07 Fonts 08 Borders/Lines 09 Conics 10 Characters 11 Flexbox 12 Variables 13 Shadow 14 Oldback Backgrounds 15 Units of measurement Quick reference guide. Like those pocket PDP-11 Instruction set cards Digital used to have. Also, why there will never be a CSS4. tools Offsite Online CSS tools Box-shadow Shadow box demo Onsite Local tools Templates

tutorial W3schools Backgrounds Borders Font Gradient-border Margins Padding Text