What Is CSS3?

CSS (Cascading Style Sheets) is the style language used to lay out web pages and define their visual style. It is used with document types such as HTML or XML and tells web browsers how those documents should be displayed. Here are some basic CSS properties, with short explanations:

1. Colours:

   /* Using a colour name */
   color: red;
   
   /* Using a hex colour code */
   color: #ff0000;
   
   /* Using an RGB colour value */
   color: rgb(255, 0, 0);

2. Background:

   /* Coloured background */
   background-color: yellow;
   
   /* Background image */
   background-image: url('image.png');

3. Text style:

   /* Font family and size */
   font-family: 'Arial', sans-serif;
   font-size: 16px;
   
   /* Bold text */
   font-weight: bold;
   
   /* Italic text */
   font-style: italic;

4. Border and radius:

   /* Border width, style and colour */
   border: 2px solid blue;
   
   /* Corner radius */
   border-radius: 5px;

5. Shadows:

   /* Add a shadow to a box */
   box-shadow: 5px 5px 10px gray;

6. Alignment:

   /* Centre the text */
   text-align: center;
   
   /* Centre the box */
   margin: 0 auto;

7. Visibility:

   /* Visibility */
   display: none; /* Hidden */
   display: block; /* Shown */

These basic properties cover some of the style options you can use when building web pages. CSS has a very wide range of properties, and you can adjust each property and value to your needs.