/* --- Global Styles --- */
body {
    font-family: 'Helvetica Neue', Arial, sans-serif;
    background: #e6f2f2;
    color: #333;
    margin: 0;
    padding: 0;
    line-height: 1.6;
}

h1, h2, h3 {
    font-family: 'Georgia', serif;
    color: #222;
    margin: 0;
}

a {
    color: #007c91;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* --- Header & Footer --- */
header, footer {
    background-color: #007c91;
    color: #fff;
    text-align: center;
    padding: 15px 20px;
}

header h1, footer p {
    margin: 0;
}

header h1 a {
    color: #fff;
    text-decoration: none;
    font-size: 1.8rem;
}

header h1 a:hover {
    text-decoration: none;
    opacity: 0.9;
}

header p {
    margin-top: 5px;
    font-size: 0.95rem;
    opacity: 0.9;
}

/* --- Homepage Grid --- */
.books-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 25px;
    max-width: 1000px;
    margin: 50px auto;
    padding: 0 20px;
}

/* --- Book Card --- */
.book-card {
    display: flex;
    flex-direction: column;
    text-align: center;
    background-color: #fff;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.book-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.15);
    text-decoration: none;
}

.book-card img {
    width: 100%;
    height: 220px;
    object-fit: contain;
    background-color: #f0f0f0;
    display: block;
}

.book-info {
    padding: 15px 12px;
}

.book-info h3 {
    margin: 0 0 6px;
    font-size: 1.05rem;
    color: #111;
}

.book-info .book-author {
    font-size: 0.85rem;
    color: #555;
    margin: 0 0 8px;
}

.book-info .book-date {
    font-size: 0.8rem;
    color: #666;
    background-color: #f5f5f5;
    display: inline-block;
    padding: 3px 8px;
    border-radius: 4px;
    margin: 0;
}

/* --- Book Detail Page --- */
.book-detail {
    max-width: 1200px;
    margin: 40px auto;
    padding: 30px;
    background-color: #fff;
    border-radius: 12px;
    box-shadow: 0 6px 25px rgba(0,0,0,0.12);
}

/* Book Header (Title + Date) */
.book-header {
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    background-color: #007c91;
    padding: 20px;
    border-radius: 8px;
    margin: -30px -30px 2rem -30px;
}

.book-title {
    font-size: 2.2rem;
    margin-bottom: 0.5rem;
    color: #fff;
}

.book-header .book-author {
    margin: 0.5rem 0;
    color: #e6f2f2;
    font-size: 1.1rem;
}

.book-header .book-date {
    font-size: 0.9rem;
    color: #e6f2f2;
    background-color: rgba(255, 255, 255, 0.15);
    display: inline-block;
    padding: 5px 10px;
    border-radius: 6px;
}

/* Cover + Summary Wrapper */
.book-summary-wrapper {
    display: flex;
    flex-direction: column;
    gap: 25px;
    margin-bottom: 40px;
}

.book-cover {
    width: 100%;
    max-width: 280px;
    display: block;
    border-radius: 12px;
    box-shadow: 0 4px 18px rgba(0,0,0,0.12);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    margin: 0 auto;
}

.book-cover:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.15);
}

.book-summary h2, .book-summary h3 {
    margin: 1.5rem 0 0.75rem;
    color: #111;
    border-bottom: 1px solid #e0e0e0;
    padding-bottom: 6px;
}

.book-summary h2:first-child {
    margin-top: 0;
}

.book-summary p {
    line-height: 1.7;
    color: #444;
}

/* Map Section */
.book-map {
    margin: 50px 0;
    padding: 30px 0;
    border-top: 1px solid #e0e0e0;
}

.book-map h2 {
    margin-bottom: 25px;
    font-size: 1.6rem;
    text-align: center;
}

.book-map img {
    display: block;
    max-width: 100%;
    height: auto;
    border-radius: 12px;
    box-shadow: 0 6px 18px rgba(0,0,0,0.15);
    margin: 0 auto 20px;
}

.book-map-notes {
    text-align: left;
    line-height: 1.7;
    color: #444;
}

.book-map-notes p {
    margin-bottom: 0.75rem;
}

/* Notebook Section */
.book-notebook {
    margin: 50px 0;
    padding: 30px 0;
    border-top: 1px solid #e0e0e0;
}

.book-notebook h2 {
    margin-bottom: 20px;
    font-size: 1.6rem;
}

.notebook-wrapper {
    width: 100%;
    overflow: hidden;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.notebook-wrapper iframe {
    display: block;
    width: 100%;
    min-height: 800px;
    border: none;
}

/* Code Notes Section */
.book-code-notes {
    margin: 50px 0 30px;
    padding: 30px 0;
    border-top: 1px solid #e0e0e0;
}

.book-code-notes h2 {
    margin-bottom: 20px;
    font-size: 1.6rem;
}

.book-code-notes p {
    line-height: 1.7;
    color: #444;
    margin-bottom: 0.75rem;
}

/* Back Link */
.back-link {
    display: inline-block;
    margin-top: 30px;
    font-weight: 500;
    padding: 8px 16px;
    background-color: #f0f0f0;
    border-radius: 6px;
    transition: background-color 0.2s ease;
}

.back-link:hover {
    background-color: #e0e0e0;
    text-decoration: none;
}

/* --- Responsive Design --- */
@media (min-width: 900px) {
    .book-summary-wrapper {
        flex-direction: row;
        gap: 40px;
        align-items: flex-start;
    }

    .book-cover {
        flex-shrink: 0;
        margin: 0;
    }

    .book-summary {
        flex: 1;
    }
}

@media (max-width: 600px) {
    .book-title {
        font-size: 1.8rem;
    }
    
    .book-detail {
        padding: 20px;
        margin: 20px 10px;
    }
    
    .book-header {
        margin: -20px -20px 2rem -20px;
        padding: 15px;
    }
    
    .books-grid {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
        gap: 20px;
        margin: 30px auto;
    }
}