body {
    background:#1e1e1e;
    color:#fff;
    font-family: Arial;
    overflow-x: hidden;
}
#book {
    width: 900px;
    height: 600px;
    margin: 20px auto;
}
.page {
    background: white;
}
canvas {
    width: 100%;
    height: 100%;
}
#counter {
    text-align: center;
    margin-top: 10px;
    font-size: 16px;
}
#book.center-cover {
    transform: translateX(-220px); 
    transition: transform 0.3s ease;
}
#book.last-cover {
    transform: translateX(220px); 
    transition: transform 0.3s ease;
}
.download-btn {
    position: fixed;
    top: 20px;
    right: 25px;
    background: rgba(255,255,255,0.08);
    background-color:green;
    color: #ffffff;
    padding: 10px 18px;
    border-radius: 8px;
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    backdrop-filter: blur(6px);
    border: 1px solid rgba(255,255,255,0.15);
    transition: all 0.25s ease;
    z-index: 9999;
}

.download-btn:hover {
    background: rgba(255,255,255,0.18);
    border-color: rgba(255,255,255,0.35);
    transform: translateY(-2px);
}