*{box-sizing:border-box}

html{scroll-behavior:smooth}

body{

  margin:0;

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

  background:#f6f8fc;

  color:#172033;

  line-height:1.7;

}

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



.header{

  background:#fff;

  border-bottom:1px solid #e6ebf2;

  position:sticky;

  top:0;

  z-index:10;

}

.nav{

  max-width:1100px;

  margin:auto;

  padding:16px 22px;

  display:flex;

  align-items:center;

  justify-content:space-between;

  gap:20px;

}

.brand{

  font-weight:800;

  letter-spacing:.4px;

  font-size:18px;

}

.back{

  color:#344767;

  font-size:14px;

  font-weight:700;

}



.hero{

  background:linear-gradient(135deg,#102a43,#1f4f75);

  color:#fff;

  padding:70px 22px;

}

.hero-inner{

  max-width:900px;

  margin:auto;

}

.kicker{

  display:inline-block;

  font-size:12px;

  font-weight:800;

  letter-spacing:1.2px;

  background:rgba(255,255,255,.14);

  padding:7px 11px;

  border-radius:999px;

  margin-bottom:18px;

}

h1{

  font-size:44px;

  line-height:1.15;

  margin:0 0 18px;

}

.hero p{

  max-width:760px;

  font-size:18px;

  margin:0;

  color:#e5edf5;

}



.container{

  max-width:900px;

  margin:0 auto;

  padding:50px 22px 70px;

}

.card{

  background:#fff;

  border:1px solid #e5ebf2;

  border-radius:18px;

  padding:30px;

  margin-bottom:24px;

  box-shadow:0 8px 24px rgba(16,42,67,.05);

}

h2{

  font-size:28px;

  line-height:1.25;

  margin:0 0 15px;

}

h3{

  font-size:21px;

  margin:25px 0 10px;

}

p{margin:0 0 16px}

ul{

  margin:10px 0 0;

  padding-left:22px;

}

li{margin-bottom:8px}



.note{

  border-left:4px solid #1f6feb;

  background:#eef5ff;

  padding:18px;

  border-radius:10px;

}

.warning{

  border-left:4px solid #c77d00;

  background:#fff8e8;

  padding:18px;

  border-radius:10px;

}

.grid{

  display:grid;

  grid-template-columns:repeat(2,1fr);

  gap:16px;

  margin-top:18px;

}

.mini{

  background:#f8fafc;

  border:1px solid #e6ebf2;

  border-radius:14px;

  padding:20px;

}

.mini strong{

  display:block;

  margin-bottom:6px;

}



.links{

  display:flex;

  flex-wrap:wrap;

  gap:10px;

  margin-top:16px;

}

.links a{

  background:#eef3f8;

  padding:10px 14px;

  border-radius:9px;

  font-weight:700;

  font-size:14px;

  color:#173b61;

}



.cta{

  background:#102a43;

  color:#fff;

  text-align:center;

  padding:34px;

  border-radius:18px;

}

.cta h2{margin-bottom:10px}

.cta a{

  display:inline-block;

  margin-top:10px;

  background:#fff;

  color:#102a43;

  padding:12px 18px;

  border-radius:10px;

  font-weight:800;

}



.footer{

  border-top:1px solid #e4e9f0;

  background:#fff;

  text-align:center;

  padding:30px 20px;

  color:#617085;

  font-size:14px;

}



@media(max-width:700px){

  h1{font-size:34px}

  h2{font-size:25px}

  .hero{padding:55px 20px}

  .container{padding:35px 16px 55px}

  .card{padding:23px}

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

  .nav{padding:14px 16px}

  .brand{font-size:15px}

}

.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;

}