我用css设置的时钟为什么它左边的刻度不贴着边框?

<!DOCTYPE html>
<html lang="en">
<head>
      <meta charset="UTF-8">
      <meta name="viewport" content="width=device-width, initial-scale=1.0">
      <title>Document</title>
      <style>
            *{margin: 0;padding: 0;}
            ul{list-style: none;}
            #time{width: 400px;height: 400px;border: 10px solid black;border-radius: 50%;margin: 30px auto;}
            #time ul{width: 100%;height: 100%;position: relative;}
            #time ul li{width: 5px;height: 10px;background: black;position: absolute;left: 50%;
                        transform-origin: center 200px;
            }
            /* #time ul li:nth-child(2){transform: rotateZ(6deg);} */
      </style>
</head>
<body>
      <div id="time">
            <ul>
                  <!-- <li></li>
                  <li></li> -->
            </ul>
            <div class="shizhen"></div>
            <div class="fenzhen"></div>
            <div class="miaozhen"></div>
      </div>
      <script>
           var ul = document.querySelector("ul");
           for(var i=0;i<60;i++){
                 var li= document.createElement("li");
                 li.style.transform = 'rotate('+(i*6) + 'deg)';
                 ul.appendChild(li);

           }

      </script>
</body>
</html>

为什么右边的边框贴着时钟的圆盘边框而左边的没有贴着?

border-radius 应该是浏览器不能很好的处理这个元素