body{
    margin:0;
    font-family:Arial, Helvetica, sans-serif;
    background:#f7f8fa;
    color:#222;
    line-height:1.8;
}

header{
    background:#17375e;
    color:white;
    padding:50px 20px;
    text-align:center;
}

.back-link{
    display:inline-block;
    margin-bottom:20px;
    color:#ffd166;
    text-decoration:none;
    font-weight:bold;
}

.back-link:hover{
    text-decoration:underline;
}

header h1{
    margin:0;
    font-size:2.2rem;
}

.subtitle{
    margin-top:15px;
    color:#d8e7ff;
    font-size:1rem;
}

.lesson-container{
    max-width:900px;
    margin:50px auto;
    padding:0 20px;
}

.lesson-card{
    background:white;
    padding:35px;
    border-radius:10px;
    box-shadow:0 5px 20px rgba(0,0,0,.08);
    margin-bottom:40px;
}

.lesson-card h2{
    margin-top:0;
    color:#17375e;
}

.lesson-card h3{
    color:#17375e;
    margin-top:35px;
    margin-bottom:15px;
}

.lesson-card p{
    margin:12px 0;
}

.lesson-card strong{
    color:#17375e;
}

blockquote{
    margin:18px 0;
    padding:18px 22px;
    background:#eef4ff;
    border-left:5px solid #17375e;
    font-style:italic;
}

hr{
    border:none;
    border-top:1px solid #d9d9d9;
    margin:40px 0;
}

table{
    width:100%;
    border-collapse:collapse;
    margin:25px 0;
}

th,
td{
    border:1px solid #dcdcdc;
    padding:12px;
    text-align:left;
}

th{
    background:#17375e;
    color:white;
}

.note{
    background:#fff7df;
    border-left:5px solid #f4b400;
    padding:18px;
    margin-top:30px;
}

.next-btn{
    display:inline-block;
    margin-top:40px;
    padding:14px 28px;
    background:#17375e;
    color:white;
    text-decoration:none;
    border-radius:6px;
    transition:.25s;
}

.next-btn:hover{
    background:#29558d;
}

@media (max-width:768px){

header{
    padding:35px 15px;
}

header h1{
    font-size:1.8rem;
}

.lesson-card{
    padding:25px;
}

}

/* =========================
   FOOTER
========================= */

.legal-footer{
    margin-top:60px;
    padding:30px 20px;
    background:#17375e;
    text-align:center;
}

.legal-footer .copyright{
    margin:0;
    color:#d8e7ff;
    font-size:0.95rem;
    line-height:1.6;
}

.lesson-navigation{

display:flex;
justify-content:space-between;
align-items:center;
margin-top:50px;
gap:20px;

}

.nav-btn{

display:inline-block;
padding:14px 28px;

background:#ffb703;
color:#111;

text-decoration:none;
font-weight:bold;
border-radius:8px;

transition:.25s;

}

.nav-btn:hover{

background:#ffd166;
transform:translateY(-2px);

}

.lesson-button{

display:inline-block;
margin-top:20px;
padding:14px 28px;

background:#17375e;
color:white;

text-decoration:none;
font-weight:bold;

border-radius:8px;
transition:.25s;

}

.lesson-button:hover{

background:#29558d;
transform:translateY(-2px);

}