:root{
    --sidebar:#0F172A;
    --primary:#0891B2;
    --hover:#06B6D4;
    --bg:#F1F5F9;
    --white:#ffffff;
}

body{
    margin:0;
    background:var(--bg);
    font-family:'Segoe UI',sans-serif;
}

.sidebar{
    width:260px;
    height:100vh;
    background:var(--sidebar);
    position:fixed;
    color:white;
    padding:20px;
}

.logo-area{
    text-align:center;
    margin-bottom:30px;
}

.logo-area img{
    width:90px;
    height:90px;
    border-radius:50%;
    object-fit:cover;
}

.sidebar a{
    display:block;
    color:white;
    text-decoration:none;
    padding:12px;
    margin:8px 0;
    border-radius:10px;
}

.sidebar a:hover{
    background:var(--hover);
}

.main{
    margin-left:280px;
    padding:25px;
}

.topbar{
    background:white;
    padding:20px;
    border-radius:15px;
    margin-bottom:20px;
}

.card-box{
    background:white;
    border-radius:15px;
    padding:20px;
    box-shadow:0 2px 10px rgba(0,0,0,.08);
}

.cards{
    display:grid;
    grid-template-columns:repeat(auto-fit,minmax(220px,1fr));
    gap:20px;
    margin-bottom:25px;
}

.book-grid{
    display:grid;
    grid-template-columns:repeat(auto-fill,minmax(260px,1fr));
    gap:20px;
}

.book-card{
    background:white;
    border-radius:15px;
    overflow:hidden;
    box-shadow:0 2px 10px rgba(0,0,0,.08);
}

.book-cover{
    width:100%;
    height:260px;
    object-fit:cover;
}

.book-content{
    padding:15px;
}

.book-title{
    font-size:18px;
    font-weight:bold;
}

.price{
    color:#0891B2;
    font-size:20px;
    font-weight:bold;
}

.available{
    background:#16A34A;
    color:white;
    padding:5px 10px;
    border-radius:20px;
}

.notavailable{
    background:#DC2626;
    color:white;
    padding:5px 10px;
    border-radius:20px;
}