# Introduction to CSS (Cascading Style Sheets)
In the early days of the web, people used to style their pages using explicit styling tags such as ``, `` and `` (all of which have long been **deprecated** and should never be used today). This was inflexible, difficult to maintain, and conflated *presentation* with the document structure.
CSS emerged in the mid-90s as a way to make styling webpages easier. It's core idea was to replace explicit styling in HTML with *styling rules* which could be applied to multiple elements; this would have the benefits of (a) reducing duplication, and (b) separating styling instructions from content.
CSS works by selecting some group of elements (using a special reference called a **selector**) and defining a set of properties and values to apply to that group of elements. The general syntax for this is:
```css
selector {
property: value;
property: value;
}
```
A specific example is
```css
p {
font-size: 24px;
color: white;
background-color: green;
border-bottom: 5px solid red;
}
```
#### Adding CSS to a Webpage
To add CSS to a page, either include it
1. Inline, within an element.
2. Between two `