why do css styles override code example

Example 1: how to overwrite im css

/* this is not a standard but if you need to then do this */
.example {
  color: blue;
  color: red !important;
 /* the red color will show as it has the important thing afterwards*/
}

Example 2: css overwriting styles

body {
background-color: black;
background-color: blue !important ;
  /*
  The second background color would show since it has
  a !important afterwards, this is to overwrite css you have
  already wrote. However, this is not recomended. 
  */
}