body {
    font-family: 'Microsoft YaHei', sans-serif;
    background: #f0e6d3;
    margin: 0;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.bookshelf {
    max-width: 1200px;
    margin: 40px auto;
    background: linear-gradient(to bottom, #8b4513, #654321);
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
}

h1 {
    text-align: center;
    color: #2c3e50;
    margin-bottom: 40px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.1);
}

.shelf {
    display: flex;
    justify-content: center;
    gap: 30px;
    padding: 20px;
    background: linear-gradient(to bottom, #a0522d, #8b4513);
    border-radius: 8px;
    position: relative;
    margin-bottom: 40px;
}

.shelf::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 20px;
    background: rgba(0, 0, 0, 0.1);
    border-radius: 0 0 8px 8px;
}

.book {
    position: relative;
    width: 160px;
    height: 240px;
    background: white;
    border-radius: 5px;
    box-shadow: 5px 5px 10px rgba(0, 0, 0, 0.2);
    transition: all 0.3s ease;
    cursor: pointer;
    overflow: hidden;
    text-decoration: none;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 15px;
    text-align: center;
}

.book:hover {
    transform: translateY(-20px) rotate(5deg);
    box-shadow: 8px 8px 15px rgba(0, 0, 0, 0.3);
}

.book::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 10px;
    height: 100%;
    background: rgba(0, 0, 0, 0.1);
    border-radius: 5px 0 0 5px;
}

.solar-power {
    background: linear-gradient(135deg, #ffd700, #ff8c00);
    color: #333;
}

.world-map {
    background: linear-gradient(135deg, #4ca1af, #2c3e50);
    color: white;
}

.turbofan {
    background: linear-gradient(135deg, #606c88, #3f4c6b);
    color: white;
}

.book-title {
    font-size: 1.2rem;
    font-weight: bold;
    margin-top: 10px;
}

.book-icon {
    font-size: 3rem;
    margin-bottom: 15px;
}

@media (max-width: 768px) {
    .shelf {
        flex-direction: column;
        align-items: center;
    }

    .book {
        width: 140px;
        height: 200px;
    }
}

.footer {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    text-align: center;
    padding: 20px;
    background: rgba(0, 0, 0, 0.05);
    z-index: 100;
}

.footer-content {
    color: #666;
    font-size: 0.9rem;
}

.footer a {
    color: #666;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer a:hover {
    color: #333;
}