.books-hero {
    background: linear-gradient(135deg, #14213d, #7a1f1f);
    color: #fff;
    padding: 70px 20px;
    text-align: center;
}

.books-hero h1 {
    font-size: 42px;
    margin-bottom: 12px;
}

.books-hero p {
    font-size: 18px;
    max-width: 800px;
    margin: 0 auto;
}

.books-section {
    max-width: 1150px;
    margin: 40px auto;
    padding: 0 20px;
}

.books-section h2 {
    text-align: center;
    margin-bottom: 25px;
    color: #14213d;
}

.grade-grid,
.subject-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 20px;
}

.grade-card,
.subject-card,
.book-card {
    background: #fff;
    border-radius: 16px;
    padding: 25px;
    text-decoration: none;
    color: #222;
    box-shadow: 0 8px 24px rgba(0,0,0,0.10);
    border-top: 5px solid #d4a017;
    transition: 0.25s ease;
}

.grade-card:hover,
.subject-card:hover,
.book-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 30px rgba(0,0,0,0.16);
}

.grade-card span {
    display: block;
    font-size: 22px;
    font-weight: 800;
    color: #7a1f1f;
}

.grade-card small {
    color: #555;
}

.subject-card h3,
.book-card h3 {
    margin-bottom: 10px;
    color: #7a1f1f;
}

.book-list {
    display: grid;
    gap: 20px;
}

.back-link {
    display: inline-block;
    margin-bottom: 25px;
    font-weight: 700;
    color: #7a1f1f;
    text-decoration: none;
}

.book-info,
.pdf-box,
.resource-box,
.quiz-box {
    background: #fff;
    padding: 25px;
    border-radius: 16px;
    margin-bottom: 25px;
    box-shadow: 0 8px 24px rgba(0,0,0,0.10);
}

.pdf-box iframe {
    border: 1px solid #ddd;
    border-radius: 10px;
}

.resource-box a {
    color: #7a1f1f;
    font-weight: 700;
}

.quiz-btn {
    display: inline-block;
    margin: 8px 8px 8px 0;
    padding: 12px 20px;
    border-radius: 30px;
    background: #14213d;
    color: white;
    text-decoration: none;
    font-weight: 700;
}

.quiz-btn:hover {
    background: #7a1f1f;
}

@media (max-width: 768px) {
    .books-hero {
        padding: 45px 15px;
    }

    .books-hero h1 {
        font-size: 30px;
    }

    .pdf-box iframe {
        height: 520px;
    }
}

.books-hero{
    position:relative;
}

.hero-top-nav{
    position:absolute;
    top:20px;
    right:30px;
}

.hero-home-btn{
    display:inline-block;
    background:rgba(255,255,255,.15);
    color:#fff;
    text-decoration:none;
    padding:10px 18px;
    border-radius:30px;
    font-weight:700;
    border:1px solid rgba(255,255,255,.3);
    transition:.3s;
}

.hero-home-btn:hover{
    background:#fff;
    color:#7a1f1f;
}