*{

  box-sizing:border-box;

  margin:0;

  padding:0;

}



body{

  font-family:Arial,Helvetica,sans-serif;

  background:#f5f7fb;

  color:#1f2937;

  line-height:1.7;

}



header{

  background:#0f172a;

  color:#fff;

  padding:18px 20px;

}



.header-wrap{

  max-width:1100px;

  margin:auto;

  display:flex;

  justify-content:space-between;

  align-items:center;

  gap:20px;

}



.brand{

  font-size:18px;

  font-weight:700;

  letter-spacing:.3px;

}



.back-link{

  color:#cbd5e1;

  text-decoration:none;

  font-size:14px;

}



.back-link:hover{

  color:#fff;

}



main{

  max-width:900px;

  margin:0 auto;

  padding:50px 20px;

}



.article{

  background:#fff;

  padding:45px;

  border-radius:14px;

  box-shadow:0 8px 30px rgba(15,23,42,.08);

}



.badge{

  display:inline-block;

  background:#e0e7ff;

  color:#3730a3;

  padding:6px 12px;

  border-radius:999px;

  font-size:13px;

  font-weight:700;

  margin-bottom:18px;

}



h1{

  font-size:38px;

  line-height:1.2;

  margin-bottom:20px;

  color:#0f172a;

}



h2{

  font-size:27px;

  margin-top:38px;

  margin-bottom:14px;

  color:#111827;

}



h3{

  font-size:20px;

  margin-top:24px;

  margin-bottom:10px;

  color:#1f2937;

}



p{

  margin-bottom:18px;

}



ul{

  margin:0 0 20px 25px;

}



li{

  margin-bottom:8px;

}



.highlight{

  background:#f8fafc;

  border-left:4px solid #4f46e5;

  padding:18px;

  margin:25px 0;

  border-radius:6px;

}



.warning{

  background:#fff7ed;

  border-left:4px solid #ea580c;

  padding:18px;

  margin:28px 0;

  border-radius:6px;

}



.related{

  margin-top:40px;

  padding-top:30px;

  border-top:1px solid #e5e7eb;

}



.related a{

  color:#4338ca;

  text-decoration:none;

}



.related a:hover{

  text-decoration:underline;

}



footer{

  text-align:center;

  padding:30px 20px;

  color:#64748b;

  font-size:14px;

}



@media(max-width:700px){

  .header-wrap{

    flex-direction:column;

    align-items:flex-start;

  }



  main{

    padding:25px 12px;

  }



  .article{

    padding:25px 20px;

  }



  h1{

    font-size:30px;

  }



  h2{

    font-size:24px;

  }

}

.table-of-contents{

  margin:24px 0;

  border:1px solid #e1e6ee;

  border-radius:12px;

  background:#f8fafc;

  overflow:hidden;

}



.toc-toggle{

  width:100%;

  border:0;

  background:#071b35;

  color:#fff;

  padding:16px 18px;

  font-size:16px;

  font-weight:700;

  display:flex;

  justify-content:space-between;

  align-items:center;

  cursor:pointer;

}



.toc-arrow{

  font-size:18px;

  line-height:1;

}



.toc-content{

  display:none;

  padding:14px 22px;

}



.table-of-contents.open .toc-content{

  display:block;

}



.toc-content ul{

  margin:0;

  padding-left:18px;

}



.toc-content li{

  margin:10px 0;

}



.toc-content a{

  color:#0d3b66;

  text-decoration:none;

  font-weight:600;

}



.toc-content a:hover{

  text-decoration:underline;

}



@media(max-width:600px){

  .toc-toggle{

    padding:15px;

  }



  .toc-content{

    padding:12px 18px;

  }

}

.author-box{

    margin:30px 0;

    padding:20px;

    border:1px solid #ddd;

    border-radius:10px;

    background:#f8f9fa;

}

.author-box strong{

    display:block;

    font-size:18px;

    margin-bottom:5px;

}

.author-box span{

    display:block;

    font-size:14px;

    margin-bottom:12px;

    color:#555;

}

.author-box p{

    margin:0;

    line-height:1.6;

}