Safari should shade the first column but it does not because the span attribute is not set. Safari defaults to 0 when it should default to 1 (Use webkits element inspector to verify this)

Browsers that can style colgroup browsers that can’t style colgroup
ie 6 ie 7 Firefox 2 Opera 9 Safari 2.0.4 (419.3)

the following css is used for the styling

<style type="text/css">
      background-color: #afa;
      color: black