*{
    margin:0;
    padding:0;
    box-sizing:border-box;
    font-family:Arial, Helvetica, sans-serif;
}

body{
    background:#f4f6f9;
    color:#222;
}

header{
    display:flex;
    justify-content:space-between;
    align-items:center;
    padding:20px 40px;
    background:#111;
    color:white;
}

.logo{
    font-size:22px;
    font-weight:bold;
}

#searchBar{
    padding:8px 12px;
    border-radius:5px;
    border:none;
    width:200px;
}

nav{
    background:#222;
}

nav ul{
    display:flex;
    list-style:none;
    justify-content:center;
}

nav ul li{
    padding:15px 20px;
}

nav ul li a{
    color:white;
    text-decoration:none;
}

.hero{
    text-align:center;
    padding:60px 20px;
    background:white;
}

.hero h1{
    font-size:32px;
    margin-bottom:15px;
}

.subjects{
    padding:40px;
    max-width:1100px;
    margin:auto;
}

.subjects h2{
    margin-bottom:30px;
    font-size:26px;
}

.card{
    background:white;
    padding:20px;
    margin-bottom:20px;
    border-radius:8px;
    box-shadow:0 5px 15px rgba(0,0,0,0.05);
}

.card h3{
    margin-bottom:10px;
}

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

.card a{
    display:inline-block;
    padding:8px 15px;
    background:#111;
    color:white;
    text-decoration:none;
    border-radius:4px;
}

footer{
    text-align:center;
    padding:20px;
    background:#111;
    color:white;
    margin-top:40px;
}


body{
    font-family: Arial;
    background:#f4f6f9;
    margin:0;
    padding:40px;
}

.notes-wrapper{
    max-width:900px;
    margin:auto;
    background:white;
    padding:30px;
    border-radius:8px;
    box-shadow:0 5px 20px rgba(0,0,0,0.1);
}

h1{
    text-align:center;
}

.subtitle{
    text-align:center;
    color:gray;
    margin-bottom:30px;
}

.unit{
    margin-bottom:10px;
}

.unit-btn{
    width:100%;
    padding:15px;
    background:#111;
    color:white;
    border:none;
    cursor:pointer;
    text-align:left;
    font-size:16px;
    border-radius:5px;
}

.unit-btn:hover{
    background:#333;
}

.unit-content{
    display:none;
    padding:20px;
    background:#f9f9f9;
    border-left:4px solid #111;

}