In addition to Idriss answer:

CSS

In CSS we write code as depicted bellow, in full length.

body{
 width: 800px;
 color: #ffffff;
}
body content{
 width:750px;
 background:#ffffff;
}

SCSS

In SCSS we can shorten this code using a @mixin so we don’t have to write color and width properties again and again. We can define this through a function, similarly to PHP or other languages.

$color: #ffffff;
$width: 800px;

@mixin body{
 width: $width;
 color: $color;

 content{
  width: $width;
  background:$color;
 }
}

SASS

In SASS however, the whole structure is visually quicker and cleaner than SCSS.

• It is sensitive to white space when you are using copy and paste,

• It seems that it doesn't support inline CSS currently.

  $color: #ffffff
  $width: 800px
  $stack: Helvetica, sans-serif
  
  body
    width: $width
    color: $color
    font: 100% $stack
  
    content
      width: $width
      background:$color