*{box-sizing:border-box}

html{scroll-behavior:smooth}

body{

  margin:0;

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

  background:#f6f8fc;

  color:#172033;

  line-height:1.75;

}

a{text-decoration:none;color:inherit}

.header{

  background:#fff;

  border-bottom:1px solid #e7ebf2;

  position:sticky;

  top:0;

  z-index:10;

}

.nav{

  max-width:1100px;

  margin:auto;

  padding:16px 22px;

  display:flex;

  justify-content:space-between;

  align-items:center;

  gap:20px;

}

.brand{font-weight:800;letter-spacing:.4px}

.back{

  color:#2563eb;

  font-weight:700;

  font-size:14px;

}

main{

  max-width:900px;

  margin:auto;

  padding:55px 22px 70px;

}

.eyebrow{

  color:#2563eb;

  font-size:13px;

  font-weight:800;

  letter-spacing:1.2px;

  margin-bottom:12px;

}

h1{

  font-size:clamp(32px,6vw,52px);

  line-height:1.15;

  margin:0 0 20px;

}

h2{

  margin-top:48px;

  font-size:29px;

  line-height:1.3;

}

h3{

  margin-top:28px;

  font-size:21px;

}

p{font-size:17px}

.hero{

  background:#fff;

  border:1px solid #e7ebf2;

  border-radius:20px;

  padding:30px;

  box-shadow:0 8px 30px rgba(20,35,60,.05);

}

.note{

  margin:30px 0;

  padding:20px;

  background:#eef5ff;

  border-left:4px solid #2563eb;

  border-radius:10px;

}

.card{

  background:#fff;

  border:1px solid #e7ebf2;

  border-radius:16px;

  padding:24px;

  margin:18px 0;

}

ul,ol{font-size:17px;padding-left:24px}

li{margin:9px 0}

.grid{

  display:grid;

  grid-template-columns:repeat(3,1fr);

  gap:16px;

  margin:24px 0;

}

.grid .card{margin:0}

.cta{

  margin-top:45px;

  background:#172033;

  color:#fff;

  padding:30px;

  border-radius:18px;

}

.cta a{

  display:inline-block;

  margin-top:12px;

  padding:11px 18px;

  background:#fff;

  color:#172033;

  border-radius:8px;

  font-weight:700;

}

footer{

  border-top:1px solid #e7ebf2;

  background:#fff;

  padding:28px 22px;

}

.footer-inner{

  max-width:1100px;

  margin:auto;

  color:#657084;

  font-size:14px;

}

@media(max-width:700px){

  .grid{grid-template-columns:1fr}

  main{padding-top:35px}

  .hero{padding:22px}

  h2{font-size:25px}

}

.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;

}