how to change alignment of button in html code example

Example 1: how to change tab icon in html

<link rel="shortcut icon" href="http://sstatic.net/stackoverflow/img/favicon.ico">

Example 2: how to change hyperlink color in css

a {
  background-color: red;
  color: white;
  padding: 1em 1.5em;
  text-decoration: none;
  text-transform: uppercase;
}