:root {
    --bg-dark: #0a0d16;
    --card-bg: rgba(255, 255, 255, 0.04);
    --card-border: rgba(255, 255, 255, 0.08);
    --card-hover-bg: rgba(255, 255, 255, 0.07);
    --card-hover-border: rgba(255, 255, 255, 0.2);
    --text-primary: #ffffff;
    --text-secondary: #a0aec0;
    
    /* Vibrant, Harmonious Glow Colors for kids */
    --color-0: #ff3366; /* Red (Bass) */
    --color-1: #3399ff; /* Blue (Drums) */
    --color-2: #10b981; /* Green (Shaker Kitty) */
    --color-3: #a855f7; /* Purple (Magic Pad) */
    --color-4: #f59e0b; /* Amber (Sweet Arp) */
    --color-5: #00cccc; /* Cyan (Alien Lead) */
    --color-6: #ff66cc; /* Pink (Rainbow Chords) */
    --color-7: #06b6d4; /* Teal (Ocean Sound) */
    --color-8: #eab308; /* Yellow (Magic Chimes) */
}

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

body {
    background-color: var(--bg-dark);
    color: var(--text-primary);
    font-family: 'Outfit', sans-serif;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    align-items: center;
    overflow-x: hidden;
    padding: 2rem 1rem;
    background-image: 
        radial-gradient(at 0% 0%, rgba(99, 102, 241, 0.2) 0px, transparent 50%),
        radial-gradient(at 100% 100%, rgba(236, 72, 153, 0.15) 0px, transparent 50%);
}

.app-header {
    text-align: center;
    margin-bottom: 1.5rem;
    z-index: 10;
}

.app-header h1 {
    font-size: 3.5rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, #fbcfe8 0%, #f472b6 50%, #c084fc 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
    filter: drop-shadow(0 0 15px rgba(244, 114, 182, 0.3));
}

.subtitle {
    font-size: 1.25rem;
    font-weight: 400;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.game-container {
    position: relative;
    width: 100%;
    max-width: 800px;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    align-items: center;
    flex-grow: 1;
    justify-content: center;
}

/* Grid Layout */
.grid-section {
    width: 100%;
}

.grid-container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    width: 100%;
}

@media (max-width: 640px) {
    .grid-container {
        gap: 0.85rem;
        grid-template-columns: repeat(3, 1fr);
    }
    .app-header h1 {
        font-size: 2.5rem;
    }
    .music-card {
        padding: 1.25rem 0.75rem !important;
        height: 140px !important;
    }
    .track-emoji {
        font-size: 2rem !important;
    }
    .track-name {
        font-size: 0.95rem !important;
    }
}

/* Kid-Friendly Music Card Style */
.music-card {
    background: var(--card-bg);
    border: 3px solid var(--card-border);
    border-radius: 24px;
    padding: 1.75rem 1rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-between;
    height: 180px;
    cursor: pointer;
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(10px);
    transition: 
        border-color 0.3s ease, 
        background 0.3s ease, 
        transform 0.1s cubic-bezier(0.175, 0.885, 0.32, 1.275), 
        box-shadow 0.3s ease;
    outline: none;
    text-align: center;
}

.track-emoji {
    font-size: 3rem;
    transition: transform 0.2s ease;
}

.track-name {
    font-size: 1.15rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-top: 0.5rem;
    margin-bottom: 0.5rem;
}

/* Waveform Visualizer Indicator */
.waveform-indicator {
    display: flex;
    align-items: flex-end;
    gap: 3px;
    height: 16px;
}

.waveform-indicator span {
    display: block;
    width: 4px;
    height: 4px;
    background-color: var(--text-secondary);
    opacity: 0.2;
    border-radius: 2px;
    transition: all 0.3s ease;
}

/* Active State Styles with unique glow effects */
.music-card.active[data-track="0"] { --track-color: var(--color-0); }
.music-card.active[data-track="1"] { --track-color: var(--color-1); }
.music-card.active[data-track="2"] { --track-color: var(--color-2); }
.music-card.active[data-track="3"] { --track-color: var(--color-3); }
.music-card.active[data-track="4"] { --track-color: var(--color-4); }
.music-card.active[data-track="5"] { --track-color: var(--color-5); }
.music-card.active[data-track="6"] { --track-color: var(--color-6); }
.music-card.active[data-track="7"] { --track-color: var(--color-7); }
.music-card.active[data-track="8"] { --track-color: var(--color-8); }

.music-card.active {
    background: rgba(255, 255, 255, 0.08);
    border-color: var(--track-color);
    box-shadow: 
        0 0 25px -3px var(--track-color),
        inset 0 0 15px -3px var(--track-color);
}

.music-card.active .track-name {
    color: var(--track-color);
    text-shadow: 0 0 10px rgba(255, 255, 255, 0.2);
}

/* Constant active state wiggles for fun visual feedback */
.music-card.active .track-emoji {
    animation: gentle-shake 3s ease-in-out infinite;
}

/* Dynamic Beat Animation: JS adds/removes .pulse class on note hit */
.music-card.pulse {
    transform: scale(1.12) rotate(2deg) !important;
}

.music-card.pulse-opposite {
    transform: scale(1.12) rotate(-2deg) !important;
}

/* Wave animation when active */
.music-card.active .waveform-indicator span {
    background-color: var(--track-color);
    opacity: 1;
    animation: wave-bounce 0.8s ease-in-out infinite alternate;
}

.music-card.active .waveform-indicator span:nth-child(1) { animation-delay: 0.05s; }
.music-card.active .waveform-indicator span:nth-child(2) { animation-delay: 0.15s; }
.music-card.active .waveform-indicator span:nth-child(3) { animation-delay: 0.1s; }
.music-card.active .waveform-indicator span:nth-child(4) { animation-delay: 0.2s; }

@keyframes wave-bounce {
    0% { height: 4px; }
    100% { height: 16px; }
}

@keyframes gentle-shake {
    0%, 100% { transform: rotate(0deg) scale(1); }
    25% { transform: rotate(3deg) scale(1.03); }
    75% { transform: rotate(-3deg) scale(0.97); }
}

/* Progress bar updates */
.progress-section {
    width: 100%;
    text-align: center;
}

.progress-bar-container {
    width: 100%;
    height: 10px;
    background: rgba(255, 255, 255, 0.04);
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: 0.5rem;
    border: 2px solid rgba(255, 255, 255, 0.08);
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, #ff3366, #ffcc00, #3399ff);
    border-radius: 10px;
    width: 0%;
    box-shadow: 0 0 15px rgba(255, 51, 102, 0.7);
    transition: width 0.05s linear;
}

.progress-label {
    font-size: 1.1rem;
    color: var(--text-secondary);
    font-weight: 600;
}

#time-display {
    color: #ffcc00;
}

/* Overlays */
.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(8, 11, 22, 0.9);
    backdrop-filter: blur(15px);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
    transition: opacity 0.5s ease;
}

.overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.overlay-content {
    background: rgba(255, 255, 255, 0.05);
    border: 3px solid rgba(255, 255, 255, 0.15);
    border-radius: 32px;
    padding: 3.5rem 2rem;
    text-align: center;
    max-width: 500px;
    width: 90%;
    box-shadow: 0 30px 60px -15px rgba(0, 0, 0, 0.6);
    animation: zoom-in 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes zoom-in {
    from { transform: scale(0.8) translateY(20px); opacity: 0; }
    to { transform: scale(1) translateY(0); opacity: 1; }
}

.overlay-content h2 {
    font-size: 2.75rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    background: linear-gradient(135deg, #ffcc00, #ff3366);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.overlay-content p {
    font-size: 1.15rem;
    color: var(--text-primary);
    line-height: 1.6;
    margin-bottom: 2rem;
}

.action-btn {
    background: linear-gradient(135deg, #ff3366 0%, #eab308 100%);
    color: white;
    border: none;
    padding: 1.25rem 3rem;
    font-size: 1.3rem;
    font-weight: 800;
    border-radius: 100px;
    cursor: pointer;
    box-shadow: 0 12px 24px -6px rgba(255, 51, 102, 0.5);
    transition: all 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    font-family: inherit;
}

.action-btn:hover {
    transform: scale(1.08);
    box-shadow: 0 18px 30px -6px rgba(255, 51, 102, 0.7);
}

.action-btn:active {
    transform: scale(0.96);
}

/* Win Overlay */
.win-content {
    border-color: rgba(254, 240, 138, 0.4);
    box-shadow: 0 30px 60px -15px rgba(234, 179, 8, 0.2);
}

.win-sparkles {
    font-size: 4rem;
    margin-bottom: 1.5rem;
    animation: bounce-spin 2s ease-in-out infinite alternate;
}

@keyframes bounce-spin {
    0% { transform: translateY(0) rotate(0deg); }
    100% { transform: translateY(-15px) rotate(10deg); }
}

.win-content h2 {
    background: linear-gradient(135deg, #fef08a 0%, #eab308 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-size: 3rem;
}

.win-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.secondary-btn {
    background: transparent;
    border: 3px solid rgba(255, 255, 255, 0.25);
    color: var(--text-primary);
    box-shadow: none;
}

.secondary-btn:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: var(--text-primary);
}

/* Footer */
.app-footer {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-secondary);
    opacity: 0.5;
    text-align: center;
    margin-top: 1.5rem;
}