/* Basic Reset */
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
            color: #f8fafc;
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: 100vh;
            text-align: center;
            overflow-x: hidden;
            padding: 20px 0;
        }

        .container {
            padding: 2rem;
            width: 100%;
            max-width: 700px;
        }

        .badge {
            display: inline-block;
            background: #38bdf8;
            color: #0f172a;
            padding: 0.5rem 1rem;
            border-radius: 50px;
            font-weight: bold;
            font-size: 0.8rem;
            text-transform: uppercase;
            margin-bottom: 1rem;
        }

        h1 {
            font-size: 2.5rem;
            margin-bottom: 0.5rem;
            letter-spacing: -1px;
        }

        /* --- COUNTDOWN STYLES --- */
        .countdown-label {
            margin-top: 1.5rem;
            color: #38bdf8;
            font-weight: bold;
            font-size: 0.8rem;
            letter-spacing: 2px;
        }

        .countdown-container {
            display: flex;
            justify-content: center;
            gap: 10px;
            margin: 1rem 0 2rem 0;
            flex-wrap: wrap;
        }

        .time-box {
            background: rgba(30, 41, 59, 0.5);
            backdrop-filter: blur(10px);
            border: 1px solid rgba(56, 189, 248, 0.2);
            border-radius: 12px;
            padding: 10px;
            min-width: 75px;
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
        }

        .time-box span {
            display: block;
            font-size: 1.8rem;
            font-weight: 800;
            color: #38bdf8;
            text-shadow: 0 0 8px rgba(56, 189, 248, 0.4);
        }

        .time-box p {
            font-size: 0.6rem;
            text-transform: uppercase;
            color: #94a3b8;
        }

        /* --- CAROUSEL STYLES --- */
        .carousel-container {
            position: relative;
            margin: 1rem auto;
            overflow: hidden;
            border-radius: 16px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
            height: 380px; 
            background: #0f172a;
        }

        .carousel-track {
            display: flex;
            transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
            height: 100%;
            cursor: grab;
        }

        .carousel-track:active { cursor: grabbing; }

        .slide {
            min-width: 100%;
            height: 100%;
            position: relative;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            background-size: cover;
            background-position: center;
        }

        .slide::before {
            content: '';
            position: absolute;
            top: 0; left: 0; width: 100%; height: 100%;
            background: rgba(15, 23, 42, 0.7); 
            z-index: 1;
        }

        .slide-content {
            position: relative;
            z-index: 2;
            padding: 2rem;
        }

        .slide h3 { color: #38bdf8; font-size: 1.5rem; margin-bottom: 0.5rem; }
        .slide h2 { font-size: 1.1rem; margin-top: 1rem; color: #fbbf24; }
        .slide p { color: #cbd5e1; font-size: 1.1rem; font-family: monospace; }

        .nav-btn {
            position: absolute;
            top: 50%;
            transform: translateY(-50%);
            background: rgba(255, 255, 255, 0.1);
            backdrop-filter: blur(5px);
            border: none;
            color: white;
            width: 45px;
            height: 45px;
            cursor: pointer;
            border-radius: 50%;
            z-index: 10;
            display: flex;
            justify-content: center;
            align-items: center;
            font-size: 1.2rem;
        }

        .prev { left: 10px; }
        .next { right: 10px; }

        .dots-container {
            display: flex;
            justify-content: center;
            gap: 12px;
            margin-bottom: 2rem;
        }

        .dot {
            width: 10px;
            height: 10px;
            background: rgba(255, 255, 255, 0.2);
            border-radius: 50%;
            cursor: pointer;
        }

        .dot.active { background: #38bdf8; transform: scale(1.3); }

        /* --- VIDEO STYLES --- */
        .video-wrapper {
            position: relative;
            width: 100%;
            padding-bottom: 56.25%; /* 16:9 Aspect Ratio */
            height: 0;
            margin: 2rem 0;
            border-radius: 16px;
            overflow: hidden;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
            border: 1px solid rgba(56, 189, 248, 0.2);
        }

        .video-wrapper iframe {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
        }

        /* Song Section */
        .song-section {
            padding: 1rem;
            border-top: 1px solid rgba(255, 255, 255, 0.1);
            margin-top: 1rem;
        }

        .footer { font-size: 0.9rem; opacity: 0.6; }
        .fade-in { animation: fadeIn 1.2s ease-out; }
        @keyframes fadeIn { from { opacity: 0; transform: translateY(15px); } to { opacity: 1; transform: translateY(0); } }

        .nav-menu {
    margin-bottom: 2rem;
    display: flex;
    justify-content: center;
    gap: 25px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding-bottom: 1rem;
}

.nav-link {
    color: #94a3b8;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: all 0.3s ease;
}

.nav-link:hover {
    color: #38bdf8;
}

.nav-link.active {
    color: #38bdf8;
    border-bottom: 2px solid #38bdf8;
    padding-bottom: 5px;
}

/* --- Book Grid Layout --- */
/* --- Library Grid --- */
#book-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 20px;
    padding: 20px 0;
}

/* --- Card Design --- */
.time-box {
    display: flex;
    flex-direction: column;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(56, 189, 248, 0.2);
    border-radius: 12px;
    padding: 15px;
    transition: all 0.3s ease;
    height: 100%;
}

.time-box:hover {
    transform: translateY(-5px);
    border-color: #38bdf8;
    box-shadow: 0 10px 20px rgba(56, 189, 248, 0.1);
}

.time-box h3 {
    color: #38bdf8;
    margin: 12px 0;
    font-size: 1rem;
    line-height: 1.4;
}

/* --- Image Handling --- */
.book-img, .no-cover {
    width: 100%;
    aspect-ratio: 2/3;
    border-radius: 8px;
    object-fit: cover;
}

.no-cover {
    background: #1e293b;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #475569;
    font-size: 0.8rem;
    border: 1px dashed #334155;
}

/* --- Actions & Status --- */
.status-wrapper {
    margin-top: auto; 
    padding-top: 10px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.claim-btn, .badge {
    display: block;
    width: 100%;
    padding: 10px;
    border-radius: 8px;
    font-weight: bold;
    text-align: center;
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    border: none;
}

.claim-btn {
    background: #38bdf8;
    color: #0f172a;
    cursor: pointer;
    transition: background 0.2s;
}

.claim-btn:hover {
    background: #7dd3fc;
}

.badge {
    background: #1e293b;
    color: #64748b;
    border: 1px solid #334155;
}

.undo-link {
    background: none;
    border: none;
    color: #f87171;
    text-decoration: underline;
    font-size: 0.7rem;
    margin-top: 8px;
    cursor: pointer;
    transition: color 0.2s;
}

.undo-link:hover {
    color: #ef4444;
}

/* --- Responsive Layout --- */
@media (max-width: 600px) {
    #book-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }
}