border-spacing「テーブルの罫線の間隔」

<style type="text/css">
.common div{
  font-family   : "メイリオ", sans-serif;
  width         : 290px;
  border        : 2px solid #6495ed;
  background    : #e7e7ff;
  padding       : 10px;
}
div.cssTitle {
  margin-top    : 10px;
  background    : #6495ed;
  color         : #fff;
  font-weight   : bold;
}
.css_border_spacing_1 {
	border-collapse:separate;
	border-spacing:10px;
	border: solid 1px #000000; }
.css_border_collapse_collapse td{ border: solid 1px #ff0000;}

.css_border_spacing_2 {
	border-collapse:separate;
	border-spacing:1em 2em;
	border: solid 1px #000000; }
.css_border_collapse_separate td{ border: solid 1px #ff0000;}

</style>

<!-- html -->
<div class="common">
  <div class="cssTitle">border-spacing:10px</div>
  <div>
  <table class="css_border_spacing_1">
  <tbody>
  <tr><td>1-1</td><td>1-2</td><td>1-3</td><td>1-4</td></tr>
  <tr><td>2-1</td><td>2-2</td><td>2-3</td><td>2-4</td></tr>
  <tr><td>3-1</td><td>3-2</td><td>3-3</td><td>3-4</td></tr>
  </tbody>
  </table>
  </div>

  <div class="cssTitle">border-spacing:1em 2em</div>
  <div>
  <table class="css_border_spacing_2">
  <tbody>
  <tr><td>1-1</td><td>1-2</td><td>1-3</td><td>1-4</td></tr>
  <tr><td>2-1</td><td>2-2</td><td>2-3</td><td>2-4</td></tr>
  <tr><td>3-1</td><td>3-2</td><td>3-3</td><td>3-4</td></tr>
  </tbody>
  </table>
  </div>

</div>