/* Google Font */
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;500;600;700&display=swap');

*{
    margin:0;
    padding:0;
    box-sizing:border-box;
}

body{
    font-family:'Poppins',sans-serif;
    background:#f5f7fb;
    color:#222;
    line-height:1.6;
}

/* Container */

.container{
    width:90%;
    max-width:1200px;
    margin:auto;
}

/* Header */

header{
    background:#2563eb;
    color:white;
    padding:40px 20px;
    text-align:center;
    position:sticky;
    top:0;
    z-index:100;
    box-shadow:0 2px 10px rgba(0,0,0,.15);
}

header h1{
    font-size:2.5rem;
    margin-bottom:10px;
}

header p{
    font-size:1.1rem;
    opacity:.95;
}

.visitor{
    margin:20px auto;
    font-size:18px;
    font-weight:600;
}

#search{
    width:100%;
    max-width:550px;
    padding:14px 18px;
    border:none;
    border-radius:10px;
    outline:none;
    font-size:16px;
}

/* Subject Cards */

.subject{
    display:grid;
    grid-template-columns:repeat(auto-fit,minmax(260px,1fr));
    gap:25px;
    margin:50px 0;
}

.card{
    background:white;
    text-decoration:none;
    color:#222;
    padding:25px;
    border-radius:15px;
    box-shadow:0 5px 18px rgba(0,0,0,.08);
    transition:.25s;
}

.card:hover{
    transform:translateY(-6px);
    box-shadow:0 12px 28px rgba(37,99,235,.18);
}

.card h2{
    color:#2563eb;
    margin-bottom:12px;
    font-size:22px;
}

.card p{
    color:#666;
    font-size:15px;
}

/* Footer */

footer{
    text-align:center;
    padding:25px;
    background:#2563eb;
    color:white;
    margin-top:40px;
}

/* Subject Page */

.back-btn{
    display:inline-block;
    margin:25px 0;
    text-decoration:none;
    color:#2563eb;
    font-weight:600;
}

.subject-title{
    font-size:40px;
    color:#2563eb;
    margin-bottom:20px;
}

.toc{
    background:white;
    padding:25px;
    border-radius:12px;
    box-shadow:0 4px 12px rgba(0,0,0,.08);
    margin-bottom:40px;
}

.toc h3{
    margin-bottom:15px;
}

.toc ul{
    padding-left:20px;
}

.toc li{
    margin:10px 0;
}

.note-content{
    white-space: pre-wrap;
    font-family: "Poppins", sans-serif;
    font-size: 20px;
    line-height: 1.2;
    color: #333;
    margin-top: 15px;
}

.note{
    background:#fff;
    padding:35px;
    margin-bottom:40px;
    border-radius:12px;
    box-shadow:0 2px 10px rgba(0,0,0,.08);
}

.note h2{
    color:#2563eb;
    font-size:32px;
    margin-bottom:20px;
    border-bottom:2px solid #e5e7eb;
    padding-bottom:10px;
}

.note p{
    margin-bottom:10px;
}

/* Responsive */

@media(max-width:768px){

header h1{
    font-size:2rem;
}

.subject-title{
    font-size: 46px;
    color:#2563eb;
    margin-bottom:30px;
    font-weight:700;
}

    section{
    margin:50px auto;
}

section h2{
    margin-bottom:20px;
    color:#0d6efd;
}
/* ===========================
   About
=========================== */

.about{
text-align:center;
  padding: 50px 20px;
}

.about p{

    margin:8px 0;

}

    .profile-img {
    width: 170px;
    height: 170px;
    border-radius: 50%;
    object-fit: cover;
    border: 5px solid #4CAF50;
    box-shadow: 0 6px 20px rgba(0,0,0,0.2);
    margin: 20px auto;
    display: block;
    transition: 0.3s;
}

.profile-img:hover {
    transform: scale(1.05);
}

/* ===========================
   Social
=========================== */

.social{

    margin-top:20px;

}

.social a{

    text-decoration:none;

    color:#0d6efd;

    font-size:30px;

    margin:0 12px;

    transition:.3s;

}

.social a:hover{

    color:#198754;

}

/* ===========================
   Visitor
=========================== */

.visitor{

    text-align:center;

}

/* ===========================
   Footer
=========================== */

footer{

    margin-top:50px;

    background:#111827;

    color:white;

    text-align:center;

    padding:20px;

}

}