#a-site_contents ol{
  counter-reset:number; /*数字をリセット*/
}
#a-site_contents ol li{
  position: relative;
  padding-left: 30px;
  line-height: 1.5em;
  padding: 0.5em 0.5em 0.5em 30px;
}

#a-site_contents ol li:before{
  /* 以下数字をつける */
  position: absolute;
  counter-increment: number;
  content: counter(number);
  /*以下数字のデザイン変える*/
  display:inline-block;
  background: #00a0e8;
  color: white;
  font-family: 'Avenir','Arial Black','Arial',sans-serif;
  font-weight:bold;
  font-size: 15px;
  border-radius: 50%;
  left: 0;
  width: 25px;
  height: 25px;
  line-height: 25px;
  text-align:center;
}