Share Your Site Skins !!

Self explanatory! share some of your site skin codes!

One piece of code I use in all the skins I make is 70em Margin! Fairly simple but I really like it when I use the computer, not really useful on mobile devices though.

body {
  background-color: lightgrey;
}
#outer.wrapper {
  background-color: white;
  max-width: 70em;
  margin: auto;
  float: none;
}