Definitions

Definition List

List
Proximity
Implies the relationship between elements to help organize, ex: items that are related should be grouped together.
Alignment

A line for you're eyes to follow

examples: right alignment, center alignment and justified!

Even Subtitles, titles and descriptions count.

Its to unify and organize the page.

Repitition

Strengthen amd unifies by tying units together, its like adding accessories to an outfit.

Or just the highlights of something.

Contrast
To add more intrest you add two different elements together, or two things that are very very different together. Ex: green and red background
HTML
Hypertext Markup Language is what it means, and it is a language for computers and browsers to read it, and connect the world to computers worldwide.
CSS
To design something with style you use CSS or Cascading style sheets, so you can make borders, margins and colors and more for youre website and blogs.
Div
Div is a form of HTML language that is used for helping the browser read it