body {
    background-color: #ffffff;
    color: #000000;
    max-width: 800px;
    margin: auto;
    padding: 1em;
    line-height: 1.5;
  }
  
  a, a:visited {
    color: #0066cc;
    text-decoration: none;
  }
  a:hover {
    text-decoration: underline;
  }
  
  .menu, .article-meta, footer {
    text-align: center;
  }
  .menu { padding: 0; }
  .menu li { display: inline-block; }
  .article-meta, .menu a {
    background: #f2f2f2;
    padding: 5px;
    border-radius: 5px;
    color: #000000;
  }
  footer a, footer a:visited { color: #888; }
  hr {
    border-style: dashed;
    color: #ddd;
  }
  
  /* code */
  pre {
    border: 1px solid #000;
    background-color: #ffffff !important;
    color: #000;
    padding: 1em;
    margin-top: -5px;
    overflow-x: auto;
    overflow-y: auto;
    max-height: 600px; 
  }
  code {
    background: #f2f2f2;
    color: #000;
  }
  pre code { background: none; }
  .copy-btn {
    position: absolute;
    top: 0.4em;
    right: 0.6em;
    font-size: 0.75em;
    padding: 2px 6px;
    border: none;
    background: #555;
    color: #fff;
    border-radius: 3px;
    cursor: pointer;
    opacity: 0.7;
    z-index: 10;
  }
  
  .copy-btn:hover {
    opacity: 1;
  }

  /* misc elements */
  img, iframe, video { 
    display: block;
    margin: auto;
    max-width: 100%; 
}
  main { hyphens: auto; }
  /* blockquote */
  blockquote {
    background: #f9f9f9;
    border-left: 5px solid #ccc;
    padding: 3px 1em 3px;
    color: #333;
  }
  
  /* table */
  table {
    margin: auto;
    border-top: 1px solid #666;
    border-bottom: 1px solid #666;
    color: #000;
  }
  table thead th {
    border-bottom: 1px solid #ddd;
  }
  th, td {
    padding: 5px;
  }
  thead, tfoot, tr:nth-child(even) {
    background: #f2f2f2;
  }

  /* head */

.title {
  font-size: 2.5rem;     /* 改为适合标题的大小 */
  font-weight: bold;   /* 加粗标题 */
  margin: 1rem 0;      /* 上下留白 */
}


h1 {
  position: relative;
  font-size: 2.5rem;
  margin-top: 2rem;
  padding-bottom: 0;         /* 伪元素在线下，不占内部空间 */
  margin-bottom: 1.5rem;     /* 给线和下方内容留空 */
}

h1::after {
  content: "";
  position: absolute;
  left: 0;                   /* 从左开始 */
  bottom: 5px;             /* 在h1下面10px位置（可调） */
  height: 1px;
  width: 100%;
  opacity: 0.5;
  background-image: linear-gradient(to left, #000 30%, transparent 70%);
}

h2 {
  font-size: 2rem;
  font-weight: bold;
  border-left: 4px solid #888; 
  padding-left: 0.8rem;           
  margin-top: 2rem;              
}

h3 {
  font-size: 1.6rem;
  font-weight: 600;
}


h4, h5, h6 {
  font-size: 1.2rem;
  margin-top: 0.8rem;
}