/* showline.css */
/* 额外样式用于显示行号 */
    pre[class*="language-"] {
      position: relative;
      padding-left: 3.8em;
      counter-reset: linenumber;
    }

    pre[class*="language-"] code {
      position: relative;
      white-space: pre;
    }

    .line-numbers-rows {
      position: absolute;
      pointer-events: none;
      top: 0;
      font-size: 100%;
      left: -3.8em;
      width: 3em; /* 额外空间以便容纳行号 */
      letter-spacing: -1px;
      border-right: 1px solid #ddd;
      user-select: none;
    }

    .line-numbers-rows > span {
      counter-increment: linenumber;
    }

    .line-numbers-rows > span:before {
      content: counter(linenumber);
      display: block;
      padding-right: 0.8em;
      text-align: right;
    }

    .copy-btn {
      position: absolute;
      top: 0;
      right: 0;
      margin: 8px;
      padding: 0.25em 0.5em;
      background-color: #007bff;
      color: white;
      border: none;
      border-radius: 4px;
      cursor: pointer;
    }

    .position-relative {
      position: relative;
    }

    .copy-message {
      display: inline-block;
      margin-left: 10px;
      color: green;
    }

    body{
      padding: 2em;
    }